Using a generator to power a water well pump

[TheGoose]

Thanks for your vote of confidence. If you had read the first post, I said it was at least double.

According to Franklin, starting current can be as high as 6 times running current. Luckily, it's only for a moment. Once the motor gets started it should drop down to normal levels.

Also I took the time to list a chart which shows which gensets are recommend (by the manufacturer) to start/run a well pump.

The only thing I see that's wrong is in the first post of the thread.

Starting amperage is THREE times running amperage, not two times. That's standard acceptable practice according to the NEC.

 

[Carl_NH]

Goose,

I think 6x is a bit high. The specs from Franklin and Goulds in the pump manual is below.

Also they state for a 2 wire motor the genset rating should be 50% higher than these #s.

So for a 1 HP it states 4KW then add 50% so 6KW..

 

[MikeInMaine]

Sorry if this point has already been made by others in this thread. If your generator has an "auto idle," "gas saver," or similar feature which slows down the idle when there is no load applied to the generator, you should turn off this feature for motor loads such as a well pump, compressor, etc.

 

[Pilot]

Goose,

Thanks for the posts and your expertise.

I am currently looking into maybe getting a standby generator for the house and the power draw for the well is my biggest concern.

Our well is 110 ft. deep, water is about 60 ft. Pump is a Red Jacket, 1/2 hp, wiring is 10 ga., about 140 ft. long. Well folks urge me to go to 3/4 hp when the pump needs to be replaced--it's 19 years old now.

I now have a 6000W portable generator--there is no peak load rating listed anywhere.

I have a transfer switch.

We run the refrigerator, freezer, furnace fan, some lights, the well and maybe a couple other things I don't remember. No A/C, no stove.

When the well comes on, the lights dim and the generator lugs down for half a second, maybe a little more.

Maybe I'm just being too conservative, but I wonder if that 6KW unit is sufficient for a future 3/4 hp pump while running other stuff. If it isn't, then we'll go ahead with the standby genset, which should let us run more stuff as well.

So, Goose, what do you think?

 

[chopped]

Im curious why they recomend a 3/4 hp? I have had 1/3 hp for yars and no troubles. Reciently when I replaced I went to 1/2 hp and its fine no noticable difference.I was told that a 3/4 was overill . I am at about 114 foot down and maybe 15 foot frok house to well head. number 12 wire..

 

[TheGoose]

Carl,

I'm just quoting what they told me in Franklin pump school. Can't find the document, else I would post it.

2-wire motors usually do require a bit more to start. One reason to consider going 3-wire with a full size (cap start/cap run) C-box.

Goose,

I think 6x is a bit high. The specs from Franklin and Goulds in the pump manual is below.

Also they state for a 2 wire motor the genset rating should be 50% higher than these #s.

So for a 1 HP it states 4KW then add 50% so 6KW..

 

[arrow]

Goose,

Thanks for the posts and your expertise.

I am currently looking into maybe getting a standby generator for the house and the power draw for the well is my biggest concern.

Our well is 110 ft. deep, water is about 60 ft. Pump is a Red Jacket, 1/2 hp, wiring is 10 ga., about 140 ft. long. Well folks urge me to go to 3/4 hp when the pump needs to be replaced--it's 19 years old now.

I now have a 6000W portable generator--there is no peak load rating listed anywhere.

I have a transfer switch.

We run the refrigerator, freezer, furnace fan, some lights, the well and maybe a couple other things I don't remember. No A/C, no stove.

When the well comes on, the lights dim and the generator lugs down for half a second, maybe a little more.

Maybe I'm just being too conservative, but I wonder if that 6KW unit is sufficient for a future 3/4 hp pump while running other stuff. If it isn't, then we'll go ahead with the standby genset, which should let us run more stuff as well.

So, Goose, what do you think?

I have a 1/2 hp pump that is 350' deep. At start up, gen box meter reads a spike to 1750w and then settles down less than a quarter of that. This is with a 5000w 6250 surge generator that is powering the rest of the house (freezer,refer, lights, microwave, coffee pot, hair dryer, flat screen tv and boiler for hot water). It lugs a bit and lights get slightly dim for a very brief time when pump comes on but it is something I can easilty live with as I never have to pay attention about what's running when something else is on. It just plows through no matter what. I even have the throttle adjusted down so I can get 12 hours on a 5 gal tank and still everything just keeps going. First 1/2 hp pump lasted 25 years with a family of 5. Replaced it with another 1/2hp.

 

[TheGoose]

Not a whole lot of difference between a 3/4 and a 1/2 HP pump.

I would think that the 6KW would be plenty of juice. The brand of the generator means just as much as the rated amperage.

Goose,

Thanks for the posts and your expertise.

I am currently looking into maybe getting a standby generator for the house and the power draw for the well is my biggest concern.

Our well is 110 ft. deep, water is about 60 ft. Pump is a Red Jacket, 1/2 hp, wiring is 10 ga., about 140 ft. long. Well folks urge me to go to 3/4 hp when the pump needs to be replaced--it's 19 years old now.

I now have a 6000W portable generator--there is no peak load rating listed anywhere.

I have a transfer switch.

We run the refrigerator, freezer, furnace fan, some lights, the well and maybe a couple other things I don't remember. No A/C, no stove.

When the well comes on, the lights dim and the generator lugs down for half a second, maybe a little more.

Maybe I'm just being too conservative, but I wonder if that 6KW unit is sufficient for a future 3/4 hp pump while running other stuff. If it isn't, then we'll go ahead with the standby genset, which should let us run more stuff as well.

So, Goose, what do you think?

 

[BobRip]

I have a 1/2 hp pump that is 350' deep. At start up, gen box meter reads a spike to 1750w and then settles down less than a quarter of that. This is with a 5000w 6250 surge generator that is powering the rest of the house (freezer,refer, lights, microwave, coffee pot, hair dryer, flat screen tv and boiler for hot water). It lugs a bit and lights get slightly dim for a very brief time when pump comes on but it is something I can easilty live with as I never have to pay attention about what's running when something else is on. It just plows through no matter what. I even have the throttle adjusted down so I can get 12 hours on a 5 gal tank and still everything just keeps going. First 1/2 hp pump lasted 25 years with a family of 5. Replaced it with another 1/2hp.

You have adjusted the throttle down? This will reduce the frequency and voltage and you risk burning up things like freezer and refrigerator. Highly not recommended. Your motors will run hotter. What frequency are you running?

 

[TheGoose]

I don't really know what is meant by "adjusted the throttle down". Unless you're using an inverter style gen-set, all generators must rotate at the same speed, either 1800 rpms' or 3600 rpm's. The speed never changes, even during idle. Otherwise you would not get the 60 hz (60 cycles per second). 1800 rpm generators are most costly, but use less fuel. They have an extra set (or two?) of windings in them, I think 4 poles instead of two.