To fully characterize a motor’s frequency response curve scientifically, an appliance for measuring motor performance is essential. At a minimum, measuring motor RPM under load while varying the PWM frequency will yield the frequencies where motor speed begins to drop and stall. A more sophisticated testing appliance adds sensors for measuring voltage, current, power, and torque.
The motor tester used for this Learning Guide consisted of six fundamental components:
- Test Motor
- Brake/Load Motor and Torque Converter
- RPM Sensor
- Motor Controller + Power Sensor (2ea: Test Motor and Brake/Load Motor)
- 2020 Aluminum Extrusion Hardware
The motor tester's code, written in CircuitPython, exercises the test motor, applies a braking current to the brake motor to simulate a load, and measures the current drawn by the test motor. In addition, motor speed and torque are recorded throughout the test.
The data used to create the collection of performance charts for this learning guide were captured by this apparatus.