PWM water pump using a Motec M150

Hi guys. Using the Motec M150 to PWM a Davies Graig 150 series electric water pump. The Motec will allow between 0 and 20,000 Hz. 0 is on only. So to PWM. 1 to 20,000 Hz. I’m running it at 1,000Hz now. Would you know/recommend the optimal Hz to PWM this pump. Thanks. Russell

I ran a couple of electric coolant pumps on an M1 using Half Bridge Outputs at 250hz without issue.

M1 using Half Bridge Outputs at 250hz without issue.

Hi David, were you only using the half bridge? No SSR? Was just discussing this option with a mate, but ultimately, wouldn't know if we would exceed the half bridge without testing it and the systems restriction.

What engine was this on?

Yes, I directly controlled the pumps using the Half-Bridge output (essentially a built-in Solid State Relay, with a 12 amp low-side switching capability). I'm sorry I don't know what the pump was, it was fitted OEM with the Ginetta G57 Prototype (we had dual pumps using custom firmware). Engine was LS3 and LS7 V8s.

I have used the Pierburg CWA 200 and CWA 400 pumps on other projects (Honda K20 and another LS-based). These have a separate PWM input that can be driven by any low-current output. We did power the pump on the LS using a PDM, and as I recall it drew about 13A at full load (and only 7-10 amps if the air was not completely bled and the car was overheating!).

Hope that helps.

Very helpful! Thanks David.

I'll see if I can borrow a pump off someone and try controlling it from the ECU. Main concern is the half bridge only has 4A RMS.

Cheers,

Shane