Help with choosing a generator

We had our well drilled last Friday. It went very good and we have Lots of water at 140 ' . With a 40' water colume in the casing.
I bought a deep well pump at Home Depot yesterday.
3/4 horse , 230 volt . Rated for 10 gallons per minute at 125 through 175 feet depth.
I will be building a well house this month and will hang the pump after that is completed.
We are off grid and run generators for our electrical needs.
Currently my only generator with a 230 volt outlet is an old Honda EG3500.
I do not know if it will run the pump, but would be very surprised if it did.
I will be filling our holding tank weekly in the house which is 200 feet from the well.

My question for anyone that actually understands electricity.
How big a generator do I need to run this pump ? I estimate the generator will only run for an hour per week . If things work the way the box says it should take less than 1/2 hour to fill my tank . Household water pressure will be handled by a separate 12 volt pump.
Thank you in advance !

 

Check out the Harbor Freight 9000 watt. More than enough power and less than $1000. I run my entire household with a 1-1/4 hp submersible with no problem during power outages. Also put a tri-fuel carb on it…can burn unleaded, propane, or natural gas with minimal adjustment.

 

Thank you. Unfortunately Harbor freight is unobtainable here due to shipping. Is your well pump a deep well 230 volt ?

 

I can't afford a Honda generator this winter. But have Generac, Champion, DeWalt and I don't know what others near me in Fairbanks.

 

We have a Harbor Freight 9000 watt. My only comment is it's so loud that it will keep the neighbors up, but easy to know it's still running. Does seem to work well and keep us and a neighbor with some power during an outage.

 

First I have a question.
When you say 40' of water are you referring to the measurement being from the point up or the top down? You don't want a pump to run out of the curve as it will overload.
Did you buy a 2 or 3 wire pump ?
2 wire pumps need a larger generator to start than 3 wire ones.
Amps x volts = watts.

 

I double checked and... it looks as though you might try your Honda EG3500 first. If it'll be the only thing drawing power, when you're running the pump, looks as tho it should do it. And, you won't be out any extra cash. Looks as though 7.8 amps is a typical draw on a 3/4 hp pump.

 

Wow, thank you all !!
The well pump will be the only thingthat will be running at one time when pumping. The well is 140 ' deep the water colume goes up to 95 ish feet. I will hang the pump at 130 feet. Reports from this area , my neighbors is that the water table fluctuates around 15' seasonally. And this year was a dry year so I think that will be a good depth.

 

Yes, 180 foot. 1-1/4 hp 230 volts.

 

I have a very similar set up with my well. A 3750 watt power mate generator would start my 20 amp 220 volt 1’ish hp pump but just barely. Really bogged generator down and occasionally would trip overload breaker. Much prefer to use my 10kw welder generator when I need to run the well.

I would suggest looking into a soft start pump or a bigger generator. Soft start basically allows electric devices to safely slowly build up to full power eliminating peak power surge on startup and greatly lowers generator power requirements.

 

What MasterMech said is missing the starting multiplier. Your pump will have 3-4 times full load amps as inrush current. If the inertia in the generator is not enough to power through that it will bog. When it bogs the voltage will dip and when the voltage drops the amps go up creating a cycle of issues. A 3 wire pump starts much easier than a 2 wire one as the capacitors really help.
Also 10' is a bit close to the point. I would suggest a throttling valve be installed in the discharge line as with water at 95' filling a unpreasurised storage tank you risk running out of the curve and into motor overload territory.
In my opinion th eg3500 is too borderline and a larger one should be purchased.

 

Keep in mind that inrush (starting) amps is normally 3 times running amperage. If the draw is 7.8 amps, the starting amps will be 23.

 

Additionally, while I own a Champion gas power inverter genny which I use with the RV and to power corded tools in the field (I put it in the bed of the side by side, I much prefer our 30 KW diesel standby generator for backup power and if I was looking at an off grid scenario (which I'm not), I'd still lean toward a stationary unit, either diesel or gas powered over any portable generator.

 

With very little knowledge of your setup, I would think that allowing the discharge line to drain when the pump is not in operation would greatly reduce your starting amp requirement. If the pump is started with 100’ of water (3 atmospheres of pressure) above the ground water level in the discharge line, it will have a significantly higher electricity requirement than if it had no head pressure. It is possible that if you have no head pressure on startup, your steady state operating amperage could actually be HIGHER than your starting amperage. If for some reason you stopped the pump and then turned it back on, you would have to wait for the head pressure to drain from the line before starting again. Does that make any sense?

 

Diesel gens are the best for off grid scenario. water cooled preferred but air cool will do.
Looking at the specs of a eg3500 honda, it states the 240v receptacle can only do 12.5 amps. BUT...
You could maybe get a soft start capacitor for it and make it work. Maybe someone could confirm you can put a soft start on a well pump?
It would be the more economical option vs a new genset.

 

Not to offend but that is wrong. A centrifugal pump is a flow based load. Ie no flow discharge blocked lowest current draw.
Large centrifugal pumps are frequently started with the discharge valve closed to reduce demand charges.
Moving the same water in a circle only requires power to shear the water. Taking water rapidly changing it's velocity is where the load increases.
Then you have the check valve holding up the column of water so the churn is the same until speed is high enough to overcome and create flow.

 

Our well is 210' deep with 60' column of water and 3/4 hp 3 wire pump. Before I got our 9000 watt Rigid, we had a 5000 watt Generac. It was one of those simple, crude units with a 10 hp B&S motor with no electric start or any other niceties. It was a pain to start but more than adequate for the well. I recommend electric start.

 

No offense taken. I know very little about pumps. Is everything I said wrong or just my understanding of how the systems are typically set up? I have seen my air compressor have a much higher power demand on a cold start against a tank with 100 psi vs an empty tank. My response was purely theoretical based on rudimentary knowledge of physics. Based on what you said, however, depending on the height of the water column that is being maintained during steady state operations, it IS possible that the steady state power demand of the pump is GREATER than the start up demand depending on the rate at which centrifugal pump accelerates.. the method in which the discharge valve is managed seems to function as a method of zeroing out any head pressure to reduce start up power demand.

 

I did some more reading on the soft start option, It looks possible but only with the 3 wire pumps. The 2 wire pumps have the capacitor on the pump.
Just replying to my own curiosity.