Pololu High-Power Motor Driver 36v20 CS Problem

Support Motor controllers/drivers and motors
1

Hello
We are using the Pololu High-Power Motor Driver 36v20 CS, to drive a 24V dc motor.
The driver is controlled by PWM, but when the duty cycle goes down over 20% the motor first goes to 0 and then up to the new value.
Example

  1. Start at 80% duty cycle motor spins at 3000 rpm
  2. Send 20%
  3. The motor then goes down to 0 rpm
  4. And then up to 750 rpm

But if the decrease is under 20%

  1. Start at 80% duty cycle motor spins at 3000 rpm
  2. Send 60%
  3. The motor then goes down to 2250 rpm

Is there a workaround this problem so it goes straight to the value?

Simon Hedegaard

2

Hello, Simon.

It is unlikely that this behavior is from our driver board. Do you have access to an oscilloscope? It would be useful to look at your PWM signals to see what they are doing. Separately, how long does it take your motor to go from 0 RPM to the commanded speed in your first example (i.e. “3. The motor then goes down to 0 rpm”)?

-Jon