The history of the DC Motor can be followed back to the 1830's, when Michael Faraday set out to devise an experiment to demonstrate whether or not a current carrying wire produced a circular magnetic field all around it. Michael Faraday found that the current carrying wire does generate a magnetic field. While Michael Faraday is often credited for the invention of the electric motor, his experiment is actually just a lab demonstration; as you can't harness it for useful work. Several scientists ever since then such as: William Sturgeon and Joseph Henry based their work on Faraday's results from his experiment and theories by the late nineteenth century the design of the DC Motor had become well established. Since then the need for DC Motor has skyrocketed for industrial applications.

Simply stated, a DC motor is designed to run on DC electric power. Two examples of pure DC motor designs are homopolar dc motor (which is uncommon), and the dc motor designed called the ball bearing motor, which is (so far) a novelty. The most common DC motor types are the brushed and brushless types, which use internal and external commutation respectively to create an oscillating AC current from the DC source - so they are not a pure DC motor design. For this discussion, we will refer to the brush dc motor type.

"Brushed" Brush DC Motor Basics
A brush DC motor design generates an oscillating current in a wound rotor, or armature, with a split ring commutator, and either a wound or permanent magnet stator. A brush dc motor rotor consists of one or more coils of wire wound around a core on a shaft; an electrical power source is connected to the rotor coil through the commutator and its brushes, causing current to flow in it, producing electromagnetism. The commutator causes the current in the coils to be switched as the rotor turns, keeping the magnetic poles of the rotor from ever fully aligning with the magnetic poles of the stator field, so that the rotor never stops (like a compass needle does) but rather keeps rotating indefinitely (as long as power is applied and is sufficient for the brush dc motor to overcome the shaft torque load and internal losses due to friction, etc.)

Many of the limitations of the classic brush DC motor are due to the need for brushes to press against the commutator. This creates friction, and as a result, sparks are created by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections - and hence coil ends - momentarily while crossing the gaps. Furthermore, the inductance of the brush dc rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes. This sparking limits the maximum speed of the machine using a brush dc motor; too-rapid sparking will overheat, erode, and possibly melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the brush dc motor. The making and breaking of electric contact will also cause electrical noise. The sparks additionally cause RFI.

Additionally, brushes eventually wear out and a brush dc motor designed machine will require maintenance - replacement, and the commutator itself is subject to wear and maintenance (on larger motors) or replacement (on small motors). The commutator assembly on a large machine is a costly element, requiring precision assembly of many parts. On a small brush dc motor, the commutator is usually permanently integrated into the rotor, so replacing it usually requires replacing the whole rotor.

Large brushes are desired for a larger brush contact area to maximize brush dc motor output, but small brushes are desired for low mass to maximize the speed at which the brush dc motor can run without the brushes excessively bouncing and sparking. Small brushes are also desirable for lower cost. Stiffer brush springs can also be used in a brush dc motor design to make brushes of a given mass work at a higher speed. However, at the cost of greater friction losses (lower efficiency) and accelerated brush and commutator wear. Therefore, brush dc motor design entails a trade-off between output power, speed, and efficiency/wear.

A: shunt       B: series       C: compound       f = field coil

There are five types of Brush DC Motor:
A. DC shunt wound motor
B. DC series wound motor
C. DC compound motor (two configurations):
    • Cumulative compound
    • Differentially compounded
D. Permanent Magnet DC Motor (not shown)
E. Separately excited (sepex) (not shown).

In a DC motor a carbon brush is a device which conducts current between stationary wires and moving parts. For a DC motor to work the coils of the DC motor rotor must be connected to complete an actual circuit. To do this slip rings are affixed to the shaft of the DC motor, and brushes attached to the rings which will be used to conduct the current. The carbon brush of the DC motor is a critical component of the DC motor but is considered the weak point in the DC motor as well because it is highly susceptible to wear especially when operating outside of operating parameters of the DC motor. Although these carbon brushes of the DC motor are considered a weak point and can wear, they can also be easily replaced with new carbon brushes for the DC motor. Although many people consider carbon brushes in a DC motor to be a "Black Art," they still serve a great purpose when subjected to the proper operating conditions. They tend to yield an excellent life and perform an amazing function for your DC motor.

There are five basic DC motor types; DC shunt mount motor, DC series wound motor, DC compound motor, DC permanent magnet motor, and DC separately excited motor. A DC shunt wound motor will run at constant speed regardless of the load. With a DC series wound motor the speed varies automatically with the load, increasing as the load decreases. This series wound motor is usually limited when heavy power demand is necessary. The DC compound motor is a combination of the DC shunt and DC series wound motors by combining the characteristics of both. These DC compound motors are usually used when severe starting conditions are met and constant speed. DC Permanent magnet motors contain permanent magnets inside, hence the name, which eliminates the need for external field current. This design yields a smaller, lighter, and energy efficient DC motor. Lastly the DC separately excited motor is used for its high torque capability at low speeds which is achieved by separately generating a high stator field current and enough armature voltage to produce the required rotor torque current.

Although the DC motor has been overshadowed by the brushless motor, the DC motor is still used in a wide range of applications. Just because we may not see DC motors very often, they really are everywhere ranging from toys to cellular phones to Jacuzzi pumps. Most automatic car windows and automatic seat adjustments are operated by DC motors. The DC motor has been an automotive industry favorite because of their relatively low cost and simple design. DC motors come in all different sizes all with different torque and speed specifications; so whatever your application may be there most likely is a DC motor that will meet your demands.

A Brush DC motor consists of two magnets facing the same direction, that surround two coils of wire that reside in the middle of the DC motor around a rotor. The coils are positioned to face the magnets, causing electricity to flow to them. This generates a magnetic field, which ultimately pushes the coils away from the magnets they are facing, and causes the rotor to turn. The current shuts off at the rotor makes a 180 turn, causing each rotor to face the opposite magnet. As the current turns on again, the electricity flows oppositely, sending another pulse that causes the rotor to turn once again. The brushes that are located within the DC motor transfer the electricity from the rotor, controlling the motor’s timing; turning it on and off when instructed.

Brushed DC Motors has a relatively inexpensive and simple design. This is a major advantage to brush DC motors, in that it’s initial start-up costs are affordable; in some cases they are even half the price of their brushless counterparts. However due to the high maintenance and moderately short lifespan, brush DC motors tend to increase in price over time, because the brushes within DC motors are apt to wearing and require replacement.

The life of the brushes, bearings, and gearbox all play a role in the longevity of a brush DC motor. Most commonly, life expectancies range from 2,000 to 5,000 hrs of operation, although actual service life varies. DC Motor design, operating current, speed, voltage, and other conditions are all contributing factors.

Always ensure the motor, as well as the motor environment is kept clean, preventing the motor from potentially encountering any type of dirt, oils, or debris. All mounting bolts should be kept tight, and the operation of the motor is in accordance with the given instructions on installation.

A DC Motor generally tends to have increased maintenance requirements in comparison to those of AC motors, because many of the motor’s components are constantly coming in contact with one another. Over time, the brushes will wear and will require replacement. Also, the interaction between the commutator and the brushes will cause debris and contaminants to settle within the DC motor, that require cleaning up after. Most commonly this occurs between the commutator and the shaft of the DC motor, as well as between the winding and the armature.

The DC Motor is one of the earliest of all electrical motor designs. It is usually the motor of choice for the majority of torque control and variable speed applications. This Tech Tip discusses the advantages and disadvantages of using a DC Brush motor in machinery and processes.

Advantages of the DC Motor
• The Brush DC Motor has a simple construction, therefore requiring a cheap drive design
• Understandable design/technology facilitates in quick application of a DC Motor.
• The design of the DC motor is quite simple, in that a permanent magnetic field is created in the by either of two means:
• Permanent magnets
• Electro-magnetic windings
• If the field is created by permanent magnets, a Brush DC Motor is said to be a "permanent magnet DC motor" (PMDC). If created by electromagnetic windings, the brush motor is often said to be a "shunt wound Brush DC motor" (SWDC). Today, because of cost-effectiveness and reliability, the PMDC motor is the motor of choice for applications involving fractional horsepower DC brush motors, as well as most applications up to about 2.0 horsepower.
• Opposing the stator field is the armature field, which is generated by a changing electromagnetic flux coming from windings located on the rotor of the Brush DC motor. The magnetic poles of the armature field will attempt to line up with the opposite magnetic poles generated by the stator field. Next, the section of the rotor where the electricity enters the rotor windings is called the commutator. The electricity is carried between the brush motor rotor and the stator by conductive graphite-copper brushes (mounted on the rotor) which contact rings on stator.

Important to Note: If a Brush DC motor suffers a loss of field (if for example, the field power connections are broken), the DC Motor will immediately begin to accelerate to the top speed which the loading will allow. This can result in the motor flying apart if the motor is lightly loaded. The possible loss of field must be accounted for, particularly with a shunt wound DC Motor.

Imagine power is supplied:

A Brush DC Motor rotates toward the pole alignment point. Just as the DC motor would get to this point, the brushes jump across a gap in the stator rings. Momentum carries the brush motor forward over this gap. When the brushes get to the other side of the gap, they contact the stator rings again and - the polarity of the voltage is reversed in this set of rings! The brush motor begins accelerating again, to the opposite set of poles. (The momentum has carried the brush motor past the original pole alignment point.) This continues as the brush motor rotates. In most DC motors, several sets of windings or permanent magnets are present to smooth out the motion.

The Brush DC Motor is simple to control speed

• Simple to control speed - Controlling the speed of a DC motor is simple. The higher the armature voltage, the faster the rotation. This relationship is linear to the brush motor's maximum speed.
• The maximum armature voltage which corresponds to the rated speed of the brush motors (these brush motors are usually given a rated speed and a maximum speed, such as 1750/2000 rpm) are available in certain standard voltages, which roughly increase in conjunction with horsepower.
• The smallest industrial-type brush motors are rated 90 VDC and 180 VDC. Larger units are rated at 250 VDC and even higher (dependent upon the individual manufacturer).
• Most industrial DC brush motors operate reliably over a speed range of about 20:1 - down to about 5-7% of base speed. This is much better performance than the comparable AC motor. This fact is in part due to the fact of the mere simplicity of control. However, it is also partly due to the fact that most industrial DC brush motors were designed with variable speed operations in mind. The addition of heat dissipation features/ devices provided for lower operating speeds of DC brush motors. • NOTE: The specialty DC motor is used in mobile applications and are typically rated 12, 24, or 48 VDC. Other tiny brush motors can be rated as low as 5 VDC. This DC Motor is very popular among hobbyists.

The Brush DC Motor is simple to control torque

• In a DC motor, torque control is also easy to accomplish. Output torque is proportional to current. So, if the current is limited, you have just limited the torque which the brush motor can achieve.
• This fact makes the DC brush motor ideal for delicate applications such as textile manufacturing.

Simple and inexpensive drive/control design

The result of this design is that variable speed or variable torque electronics are easy to design and manufacture. Varying the speed of a DC motor requires little more than a large enough potentiometer. In practice, these have been replaced for all but sub-fractional horsepower applications by the SCR and PWM drives (sometimes referred to as controls), which offer relatively precisely control voltage and current. Common drives for a DC brush motor is available at the low-end of the product offering (up to 2 horsepower). The cost will depend on the accuracy requirement, but many brush motors can be accompanied with drives ranging from $29.00 - $199.00 USD.

Disadvantages of the Brush DC Motor

• A Brush DC motor can be a bit expensive to produce, in that the raw materials have become more costly in recent year
• A Brush DC motor is less reliable in control at lowest speeds
• A Brush DC motor is physically larger than other motors with the same torque
• A Brush DC motor is much more high maintenance than are brushless motors
• A Brush DC motor becomes vulnerable to dust which decrease

Although the brushless DC motor has recently surpassed the brush DC motor because of its longetivity and reliability, the brush DC motor is still used in applications everywhere. Most commonly, the brush DC motor is found in household applications, but it can also be found being used in the industrial world because of it’s versatility in altering it’s torque to speed ratio. The brush DC motor is particularly a favorite in the automotive industry, because of their simplicity and affordability. Many automotive manufacturers use them for power windows, seats, etc. However, the brush DC motor can be found in nearly every industry ranging from computer manufacturing to textiles to toys.

A brush DC motor provides precision control of speed, driven by a direct current. Noted for a particularly high ratio of torque to inertia, the brush DC motor has the potential to supply three to four times more torque than it’s rated torque. If needed, it can even provide up to five times more than the rated torque, without stalling. A Brush DC motor consists of six different components: the axle, armature/rotor, commutator, stator, magnets, and brushes. The brush DC motor offers stable and continuous current, using rings to power a magnetic drive that operates the motor’s armature. Perhaps one of the earliest used motors, the brush DC motor is commonly used because of the ability to vary the speed-torque ratio in almost any way.

Tech Tip - 3 Phase Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase 3 phase motor, sometimes shortened to AC Motor. Pertinent information can be found about the 3 phase motor by checking the nameplate. Advantages of Using an 3 Phase Motor • The 3 Phase Motor is of a simple design • The simple design 3 phase motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC 3 phase motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into 3 phase motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of 3 phase motors. 3. The amount of torque loading on 3 phase motors, causes slipping. • The 3 Phase Motor is of a low cost construction The 3 phase motor has the advantage of being the lowest cost motor. The AC 3 phase motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the 3 phase motor. For this reason, the AC 3 phase motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all 3 phase motors are AC considered an 3 phase motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The 3 Phase Motor operates reliably The very simple design and construction of the 3 phase motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush 3 Phase Motors, there are no brushes to replace. If an 3 Phase Motor is used in the appropriate environment, protected by an enclosure, an 3 phase motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC 3 phase motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the 3 phase motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The 3 Phase Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The 3 Phase Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the 3 Phase Motor, to cover a wide range of applications and industries, called Specialty 3 Phase Motors by most. Because of the wide range of environments in which people want to use the 3 phase motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an 3 Phase Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and 3 phase motors are usually more cost-effective overall, than are DC 3 phase motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC 3 phase motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper 3 phase motors and Servo 3 Phase Motors are more appropriate for applications wherein positioning and speed control is critical.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Drive technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, an AC Drive is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Drivers And Controllers technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, AC Drivers And Controllers are capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Drives technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, AC Drives are capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Tech Tip - AC Electric Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC electric motor, sometimes shortened to AC Motor. Pertinent information can be found about the AC electric motor by checking the nameplate. Advantages of Using an AC Electric Motor • The AC Electric Motor is of a simple design • The simple design AC electric motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC electric motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC electric motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC electric motors. 3. The amount of torque loading on AC electric motors, causes slipping. • The AC Electric Motor is of a low cost construction The AC electric motor has the advantage of being the lowest cost motor. The AC electric motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the AC electric motor. For this reason, the AC electric motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all electric motors are AC considered an AC electric motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The AC Electric Motor operates reliably The very simple design and construction of the AC electric motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Electric Motors, there are no brushes to replace. If an AC Electric Motor is used in the appropriate environment, protected by an enclosure, an AC electric motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC electric motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the AC electric motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The AC Electric Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The AC Electric Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the AC Electric Motor, to cover a wide range of applications and industries, called Specialty AC Electric Motors by most. Because of the wide range of environments in which people want to use the AC electric motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an AC Electric Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC electric motors are usually more cost-effective overall, than are DC electric motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC electric motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper electric motors and Servo Electric Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - AC Gear Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC gear motor, sometimes shortened to AC Motor. Pertinent information can be found about the AC gear motor by checking the nameplate. Advantages of Using an AC Gear Motor • The AC Gear Motor is of a simple design • The simple design AC gear motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC gear motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC gear motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC gear motors. 3. The amount of torque loading on AC gear motors, causes slipping. • The AC Gear Motor is of a low cost construction The AC gear motor has the advantage of being the lowest cost motor. The AC gear motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the AC gear motor. For this reason, the AC gear motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all gear motors are AC considered an AC gear motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The AC Gear Motor operates reliably The very simple design and construction of the AC gear motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Gear Motors, there are no brushes to replace. If an AC Gear Motor is used in the appropriate environment, protected by an enclosure, an AC gear motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC gear motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the AC gear motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The AC Gear Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The AC Gear Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the AC Gear Motor, to cover a wide range of applications and industries, called Specialty AC Gear Motors by most. Because of the wide range of environments in which people want to use the AC gear motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an AC Gear Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC gear motors are usually more cost-effective overall, than are DC gear motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC gear motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper gear motors and Servo Gear Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - AC Gearmotors Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC induction motor, sometimes shortened to AC Motor. Pertinent information can be found about AC gearmotors by checking the nameplate. Advantages of Using AC Gearmotors • AC Gearmotors are of a simple design • The simple design AC gearmotors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC gearmotors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC gearmotors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC gearmotors. 3. The amount of torque loading on AC gearmotors, causes slipping. • AC Gearmotors are of a low cost construction AC gearmotors have the advantage of being the lowest cost motor. AC gearmotors are perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of AC gearmotors. For this reason, AC gearmotors are generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all gearmotors are AC induction gearmotors. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • AC Gearmotors operate reliably The very simple design and construction of AC gearmotors casue them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Gearmotors, there are no brushes to replace. If AC Gearmotors are used in the appropriate environment, protected by an enclosure, AC gearmotors can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, AC gearmotors may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of AC gearmotors in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • AC Gearmotors are made by many manufacturers , so it is relatively easy to obtain replacements (for basically the same motor) • AC Gearmotors are designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for AC Gearmotors, to cover a wide range of applications and industries, called Specialty AC Gearmotors by most. Because of the wide range of environments in which people want to use AC gearmotors, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using AC Gearmotors • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC gearmotors are usually more cost-effective overall, than are DC gearmotors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC gearmotors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper gearmotors and Servo Gearmotors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - AC Induction Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC induction motor, sometimes shortened to AC Motor. Pertinent information can be found about the AC induction motor by checking the nameplate. Advantages of Using an AC Induction Motor • The AC Induction Motor is of a simple design • The simple design AC induction motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC induction motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC induction motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC induction motors. 3. The amount of torque loading on AC induction motors, causes slipping. • The AC Induction Motor is of a low cost construction The AC induction motor has the advantage of being the lowest cost motor. The AC induction motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the AC induction motor. For this reason, the AC induction motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all induction motors are AC considered an AC induction motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The AC Induction Motor operates reliably The very simple design and construction of the AC induction motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Induction Motors, there are no brushes to replace. If an AC Induction Motor is used in the appropriate environment, protected by an enclosure, an AC induction motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC induction motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the AC induction motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The AC Induction Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The AC Induction Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the AC Induction Motor, to cover a wide range of applications and industries, called Specialty AC Induction Motors by most. Because of the wide range of environments in which people want to use the AC induction motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an AC Induction Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC induction motors are usually more cost-effective overall, than are DC induction motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC induction motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper induction motors and Servo Induction Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - AC Induction Motors Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC induction motor, sometimes shortened to AC Motor. Pertinent information can be found about AC induction motors by checking the nameplate. Advantages of Using AC Induction Motors • AC Induction Motors are of a simple design • The simple design AC induction motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC induction motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC induction motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC induction motors. 3. The amount of torque loading on AC induction motors, causes slipping. • AC Induction Motors are of a low cost construction AC induction motors have the advantage of being the lowest cost motor. AC induction motors are perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of AC induction motors. For this reason, AC induction motors are generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all induction motors are AC induction induction motors. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • AC Induction Motors operate reliably The very simple design and construction of AC induction motors casue them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Induction Motors, there are no brushes to replace. If AC Induction Motors are used in the appropriate environment, protected by an enclosure, AC induction motors can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, AC induction motors may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of AC induction motors in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • AC Induction Motors are made by many manufacturers , so it is relatively easy to obtain replacements (for basically the same motor) • AC Induction Motors are designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for AC Induction Motors, to cover a wide range of applications and industries, called Specialty AC Induction Motors by most. Because of the wide range of environments in which people want to use AC induction motors, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using AC Induction Motors • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC induction motors are usually more cost-effective overall, than are DC induction motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC induction motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper induction motors and Servo Induction Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - AC Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC motor, sometimes shortened to AC Motor. Pertinent information can be found about the AC motor by checking the nameplate. Advantages of Using an AC Motor • The AC Motor is of a simple design • The simple design AC motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC motors. 3. The amount of torque loading on AC motors, causes slipping. • The AC Motor is of a low cost construction The AC motor has the advantage of being the lowest cost motor. The AC motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the AC motor. For this reason, the AC motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all motors are AC considered an AC motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The AC Motor operates reliably The very simple design and construction of the AC motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Motors, there are no brushes to replace. If an AC Motor is used in the appropriate environment, protected by an enclosure, an AC motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the AC motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The AC Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The AC Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the AC Motor, to cover a wide range of applications and industries, called Specialty AC Motors by most. Because of the wide range of environments in which people want to use the AC motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an AC Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC motors are usually more cost-effective overall, than are DC motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper motors and Servo Motors are more appropriate for applications wherein positioning and speed control is critical.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Motor Control technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, an AC Motor Control is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Motor Controller technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, an AC Motor Controller is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC motor speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Motor Speed Control technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, an AC Motor Speed Control is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that AC speed control became a competitor. Over time, AC Motor Speed Controller technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, an AC Motor Speed Controller is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Tech Tip - AC Motors Advantages and Disadvantages The most common and simple industrial motor is the three-phase AC induction motor, sometimes shortened to AC Motor. Pertinent information can be found about AC motors by checking the nameplate. Advantages of Using AC Motors • AC Motors are of a simple design • The simple design AC motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of AC motors. 3. The amount of torque loading on AC motors, causes slipping. • AC Motors are of a low cost construction AC motors have the advantage of being the lowest cost motor. AC motors are perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of AC motors. For this reason, AC motors are generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all motors are AC induction motors. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • AC Motors operate reliably The very simple design and construction of AC motors casue them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Motors, there are no brushes to replace. If AC Motors are used in the appropriate environment, protected by an enclosure, AC motors can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, AC motors may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of AC motors in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • AC Motors are made by many manufacturers , so it is relatively easy to obtain replacements (for basically the same motor) • AC Motors are designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for AC Motors, to cover a wide range of applications and industries, called Specialty AC Motors by most. Because of the wide range of environments in which people want to use AC motors, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using AC Motors • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and AC motors are usually more cost-effective overall, than are DC motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper motors and Servo Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - Induction Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase induction motor, sometimes shortened to AC Motor. Pertinent information can be found about the induction motor by checking the nameplate. Advantages of Using an Induction Motor • The Induction Motor is of a simple design • The simple design induction motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC induction motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into induction motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of induction motors. 3. The amount of torque loading on induction motors, causes slipping. • The Induction Motor is of a low cost construction The induction motor has the advantage of being the lowest cost motor. The AC induction motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the induction motor. For this reason, the AC induction motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all induction motors are AC considered an induction motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The Induction Motor operates reliably The very simple design and construction of the induction motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Induction Motors, there are no brushes to replace. If an Induction Motor is used in the appropriate environment, protected by an enclosure, an induction motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC induction motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the induction motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The Induction Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The Induction Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the Induction Motor, to cover a wide range of applications and industries, called Specialty Induction Motors by most. Because of the wide range of environments in which people want to use the induction motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an Induction Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and induction motors are usually more cost-effective overall, than are DC induction motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC induction motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper induction motors and Servo Induction Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - Induction Motors Advantages and Disadvantages The most common and simple industrial motor is three-phase AC induction motors, sometimes shortened to AC Motor. Pertinent information can be found about induction motors by checking the nameplate. Advantages of Using Induction Motors • Induction Motors are of a simple design • The simple design induction motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of induction motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into AC induction motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of induction motors. 3. The amount of torque loading on induction motors, causes slipping. • Induction Motors are of a low cost construction induction motors have the advantage of being the lowest cost motor. induction motors are perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of induction motors. For this reason, induction motors are generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all induction motors are induction motors. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • AC Induction Motors operate reliably The very simple design and construction of induction motors casue them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Induction Motors, there are no brushes to replace. If Induction Motors are used in the appropriate environment, protected by an enclosure, induction motors can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, induction motors may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of induction motors in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • Induction Motors are made by many manufacturers , so it is relatively easy to obtain replacements (for basically the same motor) • AC Induction Motors are designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for Induction Motors, to cover a wide range of applications and industries, called Specialty Induction Motors by most. Because of the wide range of environments in which people want to use induction motors, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using Induction Motors • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and induction motors are usually more cost-effective overall, than are DC induction motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard induction motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper induction motors and Servo Induction Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - Synchronous Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase synchronous motor, sometimes shortened to AC Motor. Pertinent information can be found about the synchronous motor by checking the nameplate. Advantages of Using an Synchronous Motor • The Synchronous Motor is of a simple design • The simple design synchronous motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC synchronous motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into synchronous motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of synchronous motors. 3. The amount of torque loading on synchronous motors, causes slipping. • The Synchronous Motor is of a low cost construction The synchronous motor has the advantage of being the lowest cost motor. The AC synchronous motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the synchronous motor. For this reason, the AC synchronous motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all synchronous motors are AC considered an synchronous motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The Synchronous Motor operates reliably The very simple design and construction of the synchronous motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Synchronous Motors, there are no brushes to replace. If an Synchronous Motor is used in the appropriate environment, protected by an enclosure, an synchronous motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC synchronous motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the synchronous motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The Synchronous Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The Synchronous Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the Synchronous Motor, to cover a wide range of applications and industries, called Specialty Synchronous Motors by most. Because of the wide range of environments in which people want to use the synchronous motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an Synchronous Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and synchronous motors are usually more cost-effective overall, than are DC synchronous motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC synchronous motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper synchronous motors and Servo Synchronous Motors are more appropriate for applications wherein positioning and speed control is critical.

Tech Tip - Three Phase Motor Advantages and Disadvantages The most common and simple industrial motor is the three-phase three phase motor, sometimes shortened to AC Motor. Pertinent information can be found about the three phase motor by checking the nameplate. Advantages of Using an Three Phase Motor • The Three Phase Motor is of a simple design • The simple design three phase motors: Simply stated, a series of three windings in the exterior stator section with a simple rotating section (rotor). The changing field caused by the 50 or 60 Hertz AC line voltage causes the AC motor rotor to rotate around the axis of the motor. • The speed of AC three phase motors will depend upon these three variables: 1. The fixed number of winding sets (poles) built into three phase motors, which determines the motors base speed. 2. The frequency of the AC line voltage. Variable speed drives change this frequency to change the speed of three phase motors. 3. The amount of torque loading on three phase motors, causes slipping. • The Three Phase Motor is of a low cost construction The three phase motor has the advantage of being the lowest cost motor. The AC three phase motor is the perfect for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the three phase motor. For this reason, the AC three phase motor is generally preferred for fixed-speed applications, such as in industrial applications and for commercial and domestic applications where AC line power can be easily attached. Over 90% of all three phase motors are AC considered an three phase motor. They are found in air conditioners, washers, dryers, industrial machinery, fans, blowers, vacuum cleaners, and many, many other applications. • The Three Phase Motor operates reliably The very simple design and construction of the three phase motor causes them to be extremely reliable and are considered to be low maintenance. Unlike DC Brush Three Phase Motors, there are no brushes to replace. If an Three Phase Motor is used in the appropriate environment, protected by an enclosure, an three phase motor can expect to replace the bearings after several years of continuous operation. If the application is well designed in a protective environment, an AC three phase motor may not require the bearings to be replaced for more than 10 years. • Easily Found Replacements The wide use of the three phase motor in many different industries has resulted in easily found replacements for existing equipment repairs and/or upgrades. Many manufacturers adhere to either European (metric) or American (NEMA) standards. • The Three Phase Motor is made by many manufacturers, so it is relatively easy to obtain replacements (for basically the same motor) • The Three Phase Motor is designed in a variety of mounting styles (dependent upon the motor manufacturer). Foot Mount, C-Face, Large Flange, Vertical and Specialty. • There are many environmental styles available for the Three Phase Motor, to cover a wide range of applications and industries, called Specialty Three Phase Motors by most. Because of the wide range of environments in which people want to use the three phase motor, manufacturers have adapted by providing a wide range of packaging/enclosure designs, such as Open Drip Proof (ODP), Totally Enclosed/Fan-Cooled (TEFC), Totally Enclosed/Air-Over (TEAO), Totally Enclosed/Blower-Cooled (TEBC), Totally Enclosed/Non-Ventilated (TENV), and Totally Enclosed/Water-Cooled (TEWC) versions. Disadvantages of Using an Three Phase Motor • Expensive speed control - Speed controllers can be expensive. The electronics required to handle an AC inverter driver are considerably more expensive than those required to handle a DC motor. However, if performance requirements can be met ~meaning that the required speed range is over 1/3rd of base speed ~ AC inverters and three phase motors are usually more cost-effective overall, than are DC three phase motors and DC drives. This is especially true for applications larger than 10 horsepower, because of cost savings in the AC motor. • Inability to operate at low speeds - Standard AC three phase motors should not be operated at speeds less than about 1/3rd of the base speed, due to thermal considerations. A DC motor should be considered for these applications. • Poor positioning control - Positioning drivers and controllers can be expensive and crude. Even a vector drive is very crude when controlling a standard AC motor. Stepper three phase motors and Servo Three Phase Motors are more appropriate for applications wherein positioning and speed control is critical.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that the Variable Frequency Drive became a competitor. Over time, Variable Frequency Drive technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, a Variable Frequency Drive is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that Variable Frequency Drives became a competitor. Over time, Variable Frequency Drives technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, Variable Frequency Drives are capable of speed control with full torque attained from 0 RPM through the maximum rated speed.

Nikola Tesla invented the first AC Induction Motor in 1888, introducing a more reliable and efficient motor than the DC motor; however, AC speed control was a challenging task. When precise speed control was required, the DC motor became a replacement for the AC motor, because of its efficient and economical means of controlling speed accurately. It wasn’t until the 1980’s that Variable Speed Control became a competitor. Over time, Variable Speed Control technology eventually transformed into an inexpensive and reliable competitor to the traditional DC control. Now, a Variable Speed Control is capable of speed control with full torque attained from 0 RPM through the maximum rated speed.