VNH3SP30 Stall on direction change

Support Motor controllers/drivers and motors
1

Hey guys,

I’m having an issue. I have a VNH3SP30 connected to two Pololu 37Dx52L gearmotors and an Arduino. The motors are being driven by a 12V 2A power supply. My issue is this: If I change the direction of the motors while they are being driven at max power (PWM set to 100% duty cycle) the motor will stop moving and stall for roughly a second before starting again. I have checked the DIAG pins while this is happenning and they both remain high. Is this expected behavior? It’s not a huge deal, but I could forsee it screwing up my control schemes in the future.

Thanks,
-Jacob

2

Hi, Jacob.

If you rapidly change directions with a DC motor, you can possibly draw more than double the stall current of the motor. In your case, that would exceed your power supply’s current rating. My guess is the voltage on your power supply is dropping when you change direction. If you are also using this power supply to power your Arduino, it is probably resetting. You can address this by getting a power supply that can source more current, or by changing speed/direction more slowly.

- Ryan