Frequently Asked Questions
There are a number of types of BLDC controllers which are suited for a range of different applications, but most BLDC motor products require brushless DC controllers or BLDC drivers to operate.
With brushless DC controllers, either a Hall Effect Sensor or the back EMF (Electromotive Force) is used to run the motor. The Hall Effect uses three Hall sensors within the motor to help detect the position of the rotor. This method is primarily used ins speed detection, positioning, current sensing, and proximity switching. The magnetic field changes in response to the transducer, which varies its input voltage. A feedback is created by directly returning a voltage since the sensor operates as an analog transducer.
The distance between the Hall plate and a known magnetic field can be determined by a group of sensors (in this case, three) and the relative position of the magnet can be deduced.
A Hall sensor can act as an on/off switch in digital mode when combined with circuitry. The back EMF, also known as the Counter-Electromotive Force, is caused by a changing electromagnetic field. In a BLDC motor, the back EMF is a voltage that occurs where there is motion between the external magnetic field and the armature of the motor. In other words, the voltage is developed in an inductor by an alternating current or pulsating current. At all times, the polarity of the voltage is the reverse of the input voltage. This method is commonly used to measure the motor's position and speed indirectly.
Not necessarily; Hall sensors are only required for feedback systems. A brushless motor may be sensorless where back EMF is used to run the motor, however Hall sensors are required when using Anaheim Automation's BLDC controllers.
Our BLDC drivers are speed control drivers. Please Contact Us to discuss custom requirements, such as torque control.
Communication for MDC drivers that support it (MDCxxxUSB and similar) are all ASCII commands via RS232 or RS485.
MDC100-050101USB is the only standalone driver capable of accepting a command string.
Any “MDC” brushless motor with an integrated driver/controller can accept a command string, and uses BMC100 software:
- BLY17MDC – RS485 hardware, ASCII protocol
- BLY17MDCUSB – USB Hardware, ASCII protocol
- BLWS23MDC – RS485 hardware, ASCII protocol
- BLWS23MDCUSB – USB hardware, ASCII protocol
- BLY34MDC – RS485 hardware, ASCII protocol