Water pump will no longer work off generator.

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dahermit

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I have a 5,000 Watt generator from which I have run my essentials via power cords when ever there
is a power outage (once-twice per year). I have a 70 foot deep, well with a jet pump. It is normally
plugged into a 110 wall outlet in the basement. There is a box with points in the basement. For
some years, it ran the pump off the generator/power cord fine.

The time before the last power outage, I had difficulty getting the water pump to kick-on. After
repeatedly plugging in and out of the power cord, the pump started. The last time the power went
out, my generator and power cord would not start the pump, so I went to the hardware store and got
the heaviest gauge 25 ft. cord they had. It still would not start the pump... but when the power
came back on and I plugged the pump back into the wall outlet (118 volts via my multimeter), the pump started immediately and has run fine ever since.

I called the well company that drilled the well and installed it (about five years ago), and told them
what happened, thinking that the capacitor on the pump was going bad. They told me that "it had to
be my power cord or generator...it could not be the pump."


Today, I started the generator and stuck the leads on my multimeter into the outlets on the
generator. About 108 Volts each at the end of the 25 foot power cord also. I did the same to the wall outlet into which I plug my water pump...118 volts.

As much as my generator/25 ft. power cord has always run the pump before, why does it not do it now? The generator is still running fine (clean air filter, new plug, new oil). Personally, I still think it is the starting capacitor in the pump itself...any electricians concur?
 

Jadnashua

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A 10vac drop in 25' means that the wire gauge in that extension cord is way too small for your load. Startup current on a motor is also a heavy momentary surge which would drop the voltage even more, and is probably the issue. What size breaker is the pump on? If 20A, you'd want your extension cord to be at least 12g.
 

dahermit

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A 10vac drop in 25' means that the wire gauge in that extension cord is way too small for your load. Startup current on a motor is also a heavy momentary surge which would drop the voltage even more, and is probably the issue. What size breaker is the pump on? If 20A, you'd want your extension cord to be at least 12g.
Thanks for the input, but if you read my original post, you will see that the pump historically worked from the generator with a small gauge, 25 ft. cord. And, I did try a 12g cord and it made no difference...it still would not run. Also, the 10vac drop is also at the Generator outlet. Therefore, from the previous posts, I have concluded that the generator needs to be tweaked to get back up to 120 volts. The first chance I get, I am going to increase the running speed of the generator slightly and then see if it increases the voltage at the generator outlets...unless someone here can give me a good reason not to do it.
 

WorthFlorida

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Those generators that you buy in big box stores and usually on a two wheeled cart is the bottom end if generators. The problem is your pump motor is electrically deteriorating because those type of generators are nonregulated. A regulated generator with change the stator current to adjust the output voltage under different loads. A non regulated one will just put out as much as it can and then the voltage starts to drop under heavy loads.
AC motor on start up draw large slugs of current, therefore, the voltage drops and after it starts up the current draw is less. Then an undersized extension cord exacerbates the problem. The lower voltage to the AC motor only reduces its resistance and draws more current, more current in an undersized cord only lowers the voltage more because now it is heating adding resistance. Never run any AC motor continuously with an extension cord.
Those home generator that you see advertised, usually Kohler, are expensive and well worth it because they are regulated and designed to handle house hold loads. This also applies to washing machine, refrigerators and any heavy motor driven appliances. After Hurricane Wilma i pluged in my 5KW cart type generator to the washing machine. It barely got it going and for the spin cycle it absolutely did nothing, almost burned out the motor and there was nothing else on the generator.
Also when using a generator you must have the generator frame grounded, that is the real ground, not the AC ground.

Your pump motor winding may be burned up somewhat and also the start cap may not be 100%.
 

dahermit

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Thanks for the input, but as I posted previously, the pump worked fine off the generator for several years when the land power went out.

I have found as of a few days ago that the generator was only showing 108 Volts at the outlets. This morning it was only showing 103 Volts at the outlets. This suggested to me that perhaps, just perhaps, that the gas maybe going bad...it is the only thing I can think of at this juncture. I keep the tank full and usually put STP brand gasoline preservative in it. But, it may be going bad anyway. However, the generator starts on the first pull, as it always has. So, my next step will be to drain the gas tank and replenish with fresh gas and check the output again.
 

WorthFlorida

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Thanks for the input, but as I posted previously, the pump worked fine off the generator for several years when the land power went out.

When the the pump worked with the generator, was the output voltage ever measured?
If this is becoming a concerning problem with power outages, ask family and friends if any of them have a generator and try theirs. Measure the voltage, if it is around 120 volts and the motor runs, then it is your generator. If the pump still does not run off the generator and your around 120 volts, then it is the pump motor. You can rent a comparable generator and test it out.

Increasing the speed of your generator has be done carefully and you may not have a tool to measure the RPM. The generator must be running at 3600 RPM to get the 60Hz needed for the pump. When yo usay the output is 108 volts, is that when the motor is trying to start or no load? If you have a electric portable heater or a 500 watt halogen work light, connect them to the generator, turn them on and then read the voltage. A good generator your should still have 120 volt output with a light load (1000 watt vs a 5000 watt generator). If you read the owners manaul very closely it might read 5000 watt peak, not continuous.
 
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