how big a gen for 220 water pump/tank

[Barbcue]

I have a well (150 ft) with a newer water pressure pump/tank and was wondering how big a generator i would need to make sure the tank has enough juice to run like normal

The tank is fine but would like to be able to run it at the flick of a switch and
a pull on the gen..

it will only be running a few times a year or if the SHTF (not everyday)

has to be 220V capable

anybody got a similar setup ?

[Bidah]

You are doing fine, except for one pivitol piece of information. What is the wattage and amperage draw for said motor?

-Bidah

[Arizona Highlander]

I was faced with the same situation, though mine is a shallower (45’) well. I knew that, in an emergency, I could pop open the wellhead, dip a juice can (narrow enough to drop down the pipe) and bring up water 6 ounces at a time . . . but that’s pretty primitive.

So, I also went shopping for a generator. I did some checking around the electrics of my pumphouse, and the nameplates on the pump’s electric service panel showed that mine is a 1 ½ horsepower, 220v, single phase pump, and that it pulls 10 amps steady run, with a 11.5 amps start-up surge.

It’s got 15 amp fuses, so it can’t possibly go much higher than that without shutting down.

*****

So, since Voltage x Current = Power, I figured that . . .

240 volts x 10 amps = 2400 watts normal running power requirement.

240 volts x 11.5 amps = 2760 watts start-up surge power requirement.

240 volts x 15 amps = 3600 maximum possible requirement without blowing the motor’s fuses.

*****

I ended up buying an el-cheapo Coleman generator at Home Depot for something like $550. It’s rated 5000 watts continuous, and about (I don’t exactly recall offhand) 7200 watts surge. That SHOULD be more than enough to do the job.

Honestly, it’s a pretty marginal generator, but considering my harsh financial situation, it’s the best I can do right now. And, just for emergency use (I fire it up monthly to ensure that it’s always ready) it ought to do okay.

Now, go check to see what YOUR pump’s service panel says. I suspect that your pump may have greater power requirements than mine, since your water level is deeper. So, purchase a generator accordingly!

[sparkky]

Highlander,
you're right on with your calculations for your application. you could actually go a little smaller, 4K-4.5K would most likely work too but more is better.

[MdlMkr 7.62]

I recommend a generator up to 50% larger in wattage than you think you need. When you buy the best you're not sorry (a lesson I've learned a few too many times).

7.62

[Jon Frum]

Make shure you isolate the pump so that you don't energize the power grid and ZAP some poor lineman!

[Bidah]

I am not so sure on the bigger is always better routine.. time will tell for my current situation. What I really need is about an 8kw backup genset, since the charge controller can only pull 32 amps at 110v max. Instead, thinking bigger is better, I got a 15kw genset. Now this thing can run about 140 amps at 110 continuous duty, so it is huge. Sadly there isn't much between 8kw and 15kw. So, in reality it just loafs along most of the time. Supposedly this will help it last longer, we shall see.

-Bidah

[MdlMkr 7.62]

65 amps per leg at 120v. Make sure you balance your legs.

7.62

[sparkky]

I am not so sure on the bigger is always better routine.. time will tell for my current situation. What I really need is about an 8kw backup genset, since the charge controller can only pull 32 amps at 110v max. Instead, thinking bigger is better, I got a 15kw genset. Now this thing can run about 140 amps at 110 continuous duty, so it is huge. Sadly there isn't much between 8kw and 15kw. So, in reality it just loafs along most of the time. Supposedly this will help it last longer, we shall see.

-Bidah

I know what you mean. I had the chance to get an older Onan 20KW propane genny awhile back even tho is it bigger than I would have needed. But it came from a customer of our company and I got the maintence records back to the mid 90's. It was in service till the day I picked it up.
Damn thing is powered by a 300 6cyl Ford engine which is great for parts/working on but I'm thinking BAD for long term fuel consumption. But I have a smaller one for more long term use. Best of both worlds I guess.

[Bidah]

sparky,

Yeah, I bet that would eat up some propane just idling. Mine uses a 1.5L Misubishi engine. While it is a good engine (I would prefer the Toyota 22R engine), the cam/lifter maintenance is a pain. At least with propane they do last longer than gas..

-bidah

[MdlMkr 7.62]

Yeah too big aint good. We had a Onan 20kw powered by a 4 cyl inline engine. What a gas guzzler and noisey!!! We upgraded to a 15Kw NG / LPG powered unit with it's own sub panel and auto start when power is interupted. Very quiet too. Engine life is 3000 hours on gasoline. Maybe 50% more with NG. 15 KW will run everything we need in our house.

7.62

[Arizona Highlander]

My “ambition” someday is to get myself a roughly 12-15 KW generator, and have it hardwired into the house's system. There’s no natural gas available in my area, so I’d instead want to go with a separate, dedicated propane tank - just for the generator. In a power-out situation, I’d be ready to go!

That kind of setup would probably cost a fortune, though . . .

[MdlMkr 7.62]

Our genset was $2300 at Home Despot. I'm an electrician so I did the install myself. I don't know how much a propane pig goes for but I don't imagine it's that much. Maybe $4000 total.

7.62

[Barbcue]

thanks for the input guys,, tomarrow i will go down to my well and write down everything i can find and then post it..ill be buying a honda as soon as we can figure what i need..i will have my transfer switch profesionally installed
as i dont want anybody to get fryed..

thanks
Barbcue

[Bidah]

My 15KW Liquid cooled Generac was about 3k.

-bidah

[MdlMkr 7.62]

We (my wife and I) bought ours at Home Despot last summer for $2299 on clearance. The Flint Michigan stores may still have some available. Home Depot will transfer it to another store for free. To anyone whose interested, maybe check with your local H. D. ?

7.62

[Barbcue]

OKay, here is what it is.

Amtrol tank

switch control box said this on it.

volts 230
HZ 60
RPM 3450
AMP 4.8
SF Max Amp 5.9
KW .37
SF 1.6

is this enough info to figure out what size genny to purchase ?

thanks
Barbcue

[MdlMkr 7.62]

"OKay, here is what it is.

Amtrol tank

swith control box said this on it.

volts 230
HZ 60
RPM 3450
AMP 4.8
SF Max Amp 5.9
KW .37
SF 1.6

is this enough info to figure out what size genny to purchase ?

thanks
Barbcue"

Okay it's a 220v motor and it draws a max of 5.9 amps (call it 6 amps for easier math). Start up load on an electric motor is 6x maximum running load so 36 amps draw. Watts = Volts x amps so 220 x 36 = 7920 watts. You'll need a generator with a SURGE watt rating of 7920w @ 220v to run this thing. At 110v that would be 15840 Watts

7.62

[Barbcue]

MdlMkr 7.62 and everybody else

Thanks for the info..
So ,,at 220 i need at least a 10 KW gen .. And at 110 it would have to be at least 20 KW ?

I was hopeing that it would fit in my pump house.. Sounds like ill have to build a weather proof box for it..

Bidah, a genarac 15 KW for 3k sounds great !

I cant wait to brew a nice big mug of STFU offgrid !!

ill post up ,once i get to the point of haveing the genset
gotta shop around a little ..

[MdlMkr 7.62]

Yeah that's right. 220v and 100 amps = 110v and 200 amps. That's why the pump is wired for 220v. That makes the current (amps) draw less. It's also why power companies run High voltage on their main lines. On main power lines they run high voltage and low amperage. Higher amperage requires larger diameter conductors and that means more $$$$ invested to the power Co.

For a whole house, I'd recommend a 15kw genset run on LPG or NG. You may also want to use synthetic oil in the motor for the oil's heat resistance.

7.62