PWM for Pump Controller?

Has anyone tried using a Pulse Width Modulator for throttling their pump motors? Radio(junk) has a circuit that looks promising: Velleman® K8004 DC to Pulse Width Modulator -
does anyone know how a circuit like this would behave with a demand pump? I’m hoping that by slowing the motor down, I can prevent cycling, without needing a $200+ WFP pump controller.

I guess no one has, or knows…

Guess you’re right- might as well give it a try :slight_smile:

Don’t let lack of response keep you from posting your results. you may be onto something.

Thanks. My only fear is wearing out the pump more quickly if I do this wrong… Then again, pump cycling is sure to wear out the pump! I’ve gotten the pump to stop cycling for now, by cranking up the pressure switch- but the increased flow is less than desirable, when I only have a 25 gallon tank. Plus I’m not too comfortable with where I have that switch set…

The PWM will allow you to control the speed of the motor, which will vary the flow rate through your pole. But if you have a valve on your pole to turn off the flow of water, the pump will still cycle whenever the pressure in your line reaches the pressure switch setting.

A way to approach the problem would be to install a bypass water line in your main feed line that only operates when the pressure in your main line exceeds a set value. the bypass line would return the water to your storage tank, which would allow your pump to run continuously. you could then use the PWM to set the speed of the motor to deliver the amount of water you wanted to flow through your pole and whenever you turned off the flow through your pole, the bypass line would let the motor keep running.

I hope I explained it clearly enough.