Soft Start 24V Pump Motor with Arduino Due

Hi All,

I need to soft start a 8 Amp 24V motor for a pump. I'd like to use a Mosfet N-Channel, but I need to start it slowly so the 280W Power Supply doesn't detect a short and shut down. It runs fine once it is running. Any suggestions?

I'm using a DUE so output is limited to 3.3 v, I can convert the output if necessary but I'd rather not...

Thanks,

Gina

PWM it :slight_smile:

Or do it old school, start it via a resistor and bridge that once it's started.

A ramped PWM sequence ought to work. Probably can start at 10 to 25% modulation to speed it
up a bit.

When a supply cannot handle full stall current you either have to manage the motor current (as here,
or by measuring and limiting the current with an explicit control loop), or choose a supply that handles
mild overloads for short periods gracefully (not by cutting out immediately).

Another issue with power motor supplies is protection against overvoltage if the motor can be overspun
mechanically.

A good (but expensive) motor controller will have programmable current limit, braking resistor and
active braking support, 4-quadrant handling and so forth.

Driving a motor from a battery is often simpler (assuming the battery is rugged enough).

septillion:
PWM it :slight_smile:

Or do it old school, start it via a resistor and bridge that once it's started.

Also really old school, use a time delay relay to short the resistor.

Paul