What are the disadvantages to running a pool pump at 120v v. 240v. Also would a 240v timer work with 120v pwr?

Question

While installing a baby fence around my pool I drilled through one of the hot wires to the pool pump. Now my pool pump only has 120v going to it. I rewired the pump to work on 120v. I am wondering if there are drawbacks to this e.g. higher electric bill or if the pump will now have to work harder and not last as long or not do as good a job? I am also wondering if the timer motor on the pump(which was a 240v timer) will still work under 120v or do I need to replace it with a 120v timer motor.

Thanks in advance for any help.

Answer 1

You probably have a dual voltage motor which will be able to run on 120v or 240v, But be careful. To switch from one voltage to another, it needs to be wired differently inside.  Some of the newer models make it easier for you. There's a  switch that you simply move from 240v to 120v and vice versa.  If you don't do this, you will burn the motor.  If you don't see the switch, then your going to have to rewire it for 120v which is considered "low voltage"in this case.  There should be a schematic on the motor which will show you how to wire it for low voltage or high voltage.  If you don't understand it, please take it to a shop to do it.  As for the wires going to the motor, it should have been sized so that you can use either voltage and still be safe, but you still need to check.  The lower voltage will pull twice as much amps as the higher voltage, which will cause the wires to get hotter.  You need to give more info on the motor to answer that (Horse power, Amperage).  I've seen a 1 HP, 14/7amp motor on a swimming pool pump that had a 20 amp breaker, and I believe it was 10awg wires,  so check the nameplate of the motor and ask again about the wire size.  As for the electric bill, it will make no difference.  You are charged by the wattage or the VA volt-amps. To get that, you multiply the voltage being used and the amperage, which will come out to the same regardless which voltage you use, But I believe that the higher voltage is more efficient.  It will make sense that with the higher voltage/ lower amperage, the motor will last longer too, because of less heat generated.  If given the choice, go with the higher voltage.  Are you sure the timer was a 240v?  It should have been using 120v even before your rewiring.  Just like a clock on an electric oven.  The oven is using 240v, but the clock is using 120v. It's wired that way inside.  You probably just didn't realize it.  So have you tried it already?  Does it even work? Do some more research on wire sizing for motors.  It's not the same method as a regular lighting circuit.  Good luck.

Answer 2

heres the simple answer in plain english:...the disavantage to running on 120 volts is the amp load is now all on one wire instead of being split in half....the vary fact that you have a dual voltage motor(you said you rewired it) tells me its 1 HP or less....as long as the length of wiring is not too long and the wires are at least 14 guage(lower numbers are bigger,better),you should be alright.

acording to my wiring chart,with an load of 10 amps,you should be able to go well over 100 feet with 14 gauge (or thicker) wire

the wire usually has the gauge stamped on its coating the amp rating is on motor

the clock motor will have to be replaced if its 240

Answer 3

The motor being designed to carry a load of 30amps @ 220 volts will still try to meet the load demand.  The voltage however is one half that now and so the actual load is 60amps.  You do realize the wire is probably not rated for 60amps, thus you risk several potentially dangerous problems.  One the wire could over heat and break anywhere also risking a fire.   And of course the motor will eventually fail being put through such a rigorous load.  

The timer on the other hand will work because the timer is 110 volts, but that should be the least of your concerns.

-- Sincerely,

-- JB

Answer 4

just pull some new wiring for the pump motor and put it back to 240 volt its not that difficult.