I have large voltage drop in domestic supply caused by 1km pwr cable run from the mains transformer.

Question

When I try to run a one HP 220v AC water pump it overheats and when I put a multimeter across the pump terminals while it's running the volage is 140v: unloaded voltage 215v. Would a voltage regulator remedy this or is ther another fix. VBR Bazzer.

Answer 1

It would seem to me that you need to take this up with the utility company that supply your power, and presumably own the transformer. I have no idea what country you are in but most places have regulations to protect consumers from such things.

If it is that you own the transformer, then it would make more sense to extend the HV cables and move the transformer than get bigger wire for the LV. This would be the same solution for the utility if its theirs.

Answer 2

The previous answers are correct.

However, there is another fix.....

You could reduce your pump size and motor to 1/3HP.

This would allow the motor to run. However, the water flow will also be reduced.... If the water is being pumped into a holding tank, this maybe a less expensive option....

Bazza

Electrical Engineer with 50 yrs experience

Answer 3

Yes, a voltage regulator would help, but at the price of using even more power.

But you really need to increase the size of the wire.  1km is a long run. If your power requirements are high, it may be cheaper to have the power company put a transformer close to your house and run HV to it.

If your power requirements are 100 amps, then (at 3280 ft x2) even #0000 Aluminum is too small. #0000 Copper would work, but would be very expensive.

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Answer 4

Increase the size of the conductor,so that you can reduce Impedence of the cable which will reduce the voltage drop across it.

The Voltage regulator idea will work out for little and medium level of fluctuation in the voltage for example between 160 V to 260 V.That too depends on your current rating.If you neet it for higher rating the cost will increase.

Answer 5

You need to increase the size of the wire on that long run.

Another possibility is solar power/batteries for the pump itself. You would either need a DC motor for the pump or an inverter for the existing motor.

see: http://www.southwestpv.com/Water_Pumping...

Answer 6

Everyone is going to hate me for saying this, and there is some risk it wouldn't work. You  also need to have considerable  technology sophistication to set it up and test it...

Assuming the wire is rated for 330VAC, a 1:1.5 or so step up transformer near the source would allow the motor to run properly. When running, the motor voltage would be about correct. However, when you turn if off, high voltage at the motor is unsafe and possible to kill motor. A compromise using maybe a  1:1.25 transformer would reduce power capability but also reduce risk.

A step further would be to feed the transformer with a  intelligent 2HP single phase VFD capable of modulating the output voltage with feedback. A simple V/Hz controller may not be able to do that. The VFD could be programmed with a voltage limit used when the motor is running to fine tune the voltage at the motor. A  current sensor at the VFD and/or transformer output would provide feedback to the VFD, or possibly another microcontroller to determine how much voltage to put out. Increase voltage to keep current at the nominal or the max allowed for your system (or the motor nameplate). However, when the current drops rapidly (motor shut off), the VFD needs to instantly revert to 220V out from the transformer. A feedback signal, perhaps a rectifier (at the pump) with a voltage divider and filter and a small wire running all the way back to the source would provide better  feedback. You might also need a shut off switch that actuates when the pump turns off to tell the controller to quickly drop the voltage.

Of course, whatever you do, make sure a qualified engineer or tech verifies its OK. Be careful, and be safe!