Reversing the polarity of a circuit.

Hi, I was wondering if anyone could help me. I use a electric waterpump to fill my fish tank but I want to get a switch so I can reverse the polarity of a circuit to make the pump SUCK? Which switch would I need to do this?

Thanks very much

Bluefunk said:

Hi, I was wondering if anyone could help me. I use a electric waterpump to fill my fish tank but I want to get a switch so I can reverse the polarity of a circuit to make the pump SUCK? Which switch would I need to do this?

Thanks very much

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A DPDT (Double Pole Double Throw).

unfortunately it's not quite that simple. Nice idea though. Is the motor AC or DC?, is it mains?, what type is it? etc. you might find that your motor only spins one way, and if you apply a reverse bias you will either bugger it up or it will function as normal (pumping and not sucking). A bit vague I know, but a little more info on the motor would help to provide a workable solution.

The other problem is that pumps are also designed to only go one way, except special ones. If it is a centrifugal type, there is no hope in hell you will be able to suck. If it a piston device (very unlikely) the the non-return valves will only allow one way opperation.

Sorry to piss on your bonfire , but you might be chaseing a lost cause. I suggest you check, that what you want to do is actually viable.

Well the pump has an inlet and an outlet, why not just swap them around. Sometimes the best idea is the simplest.

And yes most water pumps that i know of that are used in fish tanks use a centrifugal pump. No way in the world around this issue now.