HELP-with Motor speed control

I have a Solid state AC Motor speed control (2.5amp 120v.a.c) and I want to install it to control my pump. I've read a lot that a rheostat will burn out a motor super quick, and an a little concerned about this. I have also read that If I want to control the flow rate of the motor I can use a Solid state controller like the one I have, or I can install a flow meter down stream of the pump. I have both right now so I can do either or, but I'd like to have an electrical control for the motor.

For the electrical question...it has two wires? does the controller interrupt the load in? So I would wire it in between the live conductor of the plug and the motor?

any help would be greatly appreciated

You would be much better off with a ball valve on the output of the pump. This is what the manufacturers recommend.

Or you can simply bypass part of the flow back into the pump inlet. A valve on the bypass line will allow you to make very precise adjustments and not worry about overloading the pump.

Mikey said:

Or you can simply bypass part of the flow back into the pump inlet.

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So the bypass would reconnect to the out flow of the pump?

No, it would bypass to the inlet of the pump. As far as controlling a 110 vac load, you always want to break the hot leg, not the neutral.

Mikey said:

Or you can simply bypass part of the flow back into the pump inlet. A valve on the bypass line will allow you to make very precise adjustments and not worry about overloading the pump.

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How do you overload a magnetic pump?

Bsquared said:

For the electrical question...it has two wires? does the controller interrupt the load in? So I would wire it in between the live conductor of the plug and the motor?

any help would be greatly appreciated

Click to expand...

Yes, you would find a place to mount a box in which to install the controller, and you would wire it to to the hot conductor and the motor, just like you would a regular switch.

Bsquared said:

So the bypass would reconnect to the out flow of the pump?

Click to expand...

Sort of, the bypass would connect to the outlet of the pump and go to the inlet. If you wanted full flow, you block the bypass. Partial flow, you open the bypass partially.

According to March Pumps website they only recommend putting a ball valve on the output of the pump to adjust the flow.

A magnetic pump will get damaged by letting it run dry for long periods but if you stop the flow on the output the pump stays full of liquid. I have never seen a homebrewer use a diverter setup on a magnetic pump.

Do you guys have a pic of your setups?

I don't think the usual solid state speed controller is the right type for most pumps. Is it a liile box that you can hold in one hand, or has a belt clip on the back? The usual controller is only for motors with brushes, called 'universal wound' . Like routers. Bigger motors are 'inductive' and need a complex sytem of variable frequency to change speeds. Usually bigger, half a loaf of bread size? 2.5 amps sounds litttle, what is the pump motor rating?

A solid state relay doesnt control voltage, its a relay, on and off. Unless you are automating this its really not needed, just get a heavy duty switch, and 2.5A is probably really under rated for a motor anyways. Do not connect Mag drive pumps to rehostats, this burns out the coil in the body and could lead to fire and really bad beer... To control flow you would need a valve on the output side of the pump.

I built in a by pass with a 1/2in ball valve, that works great!

I have total control with minimal stress on the motor. Thanks for the help. hopefully I can get the rest of the bugs worked out in this HERMS so I can use it to brew! well at least for now I wont have to lift 8gal of hot wort!

Post some photos of your bypass setup if you can...

John Beere said:

Post some photos of your bypass setup if you can...

Click to expand...

sorry all I have is the Camera phone right now

very interesting... thanks