How much Generator for a well pump??

[Doc_Bob]

How much generator do I need for my well pump?

I looked at this page

TigerPower PTO Generators / Sizing Calculator

I was impressed how it only wanted 2000 watts for my well pump??

I thought well pumps used a lot more power??
Bob

 

[George2615]

I had a 5000W / 6250 surge generator which ran my whole house with exception to the AC units. It ran my 220V well pump, a freezer, fridge, house lights, and TV. But the lights would dim at times when the well pump came on. Eventually I upgraded to a 10KW welder / generator which has no problem running the entire house with AC if needed. If you only need it for a well pump and general lighting I'd say a 5KW generator would work fine.

 

[Highbeam]

In theory, a HP is defined as 750 or so watts. (It is exact I just don't remember-7xx) It is not the running wattage you need to worry about but the startup surge which can be as much as triple the running watts.

So your typical one HP pump runs on 750 but needs 2250 to start it up.

I would wait here for real world experience with the same voltage and HP pump in a similar depth well from which you are trying to pump. So that information would be most useful.

 

[midlf]

That Tiger Power calculator leaves a lot to be desired and makes a lot of assumptions.

I run my well pump, 1/2hp, 5.5amps, 230vac, on my 2750 watt generator with no problems. I can't run anything else at the same time, but it starts and runs the pump with no problems. However my air compressor is listed as 7amps running current, but when starting it will stop the generator dead in about 3 seconds. The difference is the magnitude of the starting current and the duration of the starting current. The compressor has a lot more starting inertia than the water pump.

 

[hockeypuck]

Do yourself a favor and buy at least a 5500 watt generator. Sooner or later you will wished you had a larger generator. I have a deep well pump and my 4500 watt just barely pulls it in with lights and refridgerator running.

Puck

 

[Dusty]

Many generators are rated at the maximum surge watts, not the true running watts. This is important when you have energy hogs such as well pumps. I know that my generator will handle the well pump starting and the oil burner firing at the same time. When I ordered the generator 20+ years ago, the salesman/engineer asked all sort of questions as to what I was going to be powering. They then built the generator to those requirements. Mine is a Winco 8000 watt propane 3600RPM with a Tecumseh OH18 engine.

 

[CurlyDave]

How much generator do I need for my well pump? ...
I was impressed how it only wanted 2000 watts for my well pump??

I thought well pumps used a lot more power??
Bob

The real answer is it depends on how many horsepower your well pump is.

I have a 3 HP well pump and the claim was I needed a 9 kw generator to start it. I bought a 15 KW beast, primarily because I could get it for $1800 new, delivered.

It has done exactly what I expected it to do & powers the pump with capacity to spare.

 

[scesnick]

I was wondering this exact same thing. But, how can I tell what HP pump I have? and if it is 100v or 220 v. ?

 

[Dusty]

Check the circuit breaker to see if it is 110 or 220. There might be a informational plate on the pump equipment itself.
Dusty

 

[cisco]

Without basic information, there's no way to respond. Is the well pump 110v or 220v, and what is its' amp draw (one can add at least a 1/3 more for the start-up load)? I've a 3500watt Honda, and it can handle 1 of my 2 well pumps, the one purposefully kept to 1/2 HP, 110 v and 12 amps (specifies 12 running, 20 start). That pump goes to my garage/apartment, and for modest irrigation. The other well has a 1HP pump at 220 volts and 15 amps (running), and the circuit breaker on the 3500watt generator trips when connected to that circuit --- so I need to bring in my 6500watt Honda to handle that one (which, when I ever get it built, will be for my main house) - but, since I'm not interested in timing the on-off cycles of the various electrical draws in my house (e.g., can't run well pump at same time as 2 refrigerators, a microwave, lights and so on), I'll upgrade to a 15KW built-in and propane powered unit when I move in.