Inverter generator with well pump ????

[IXLR8]

We have been without power for a few days now and when the dust settles I am thinking of picking up an inverter generator vs one that screams at 3600 rpm all the time. I was wondering how well an inverter generator would handle the loads of a well pump. When a well pump kicks in the initial inrush is large and the generator may be at idle and will take a certain amount of time to spin up and increase it's output to match. I was not sure how well the generator, or pump motor, would handle the miss match in generator output vs pump input demands. Any recommendations, thoughts or experiences are appreciated.
Thank you

 

[hosspuller]

Be aware of voltage requirements. Many well pumps run on 220 volts while the inverters that produce 220 are somewhat rare in smaller sizes. A high capacity inverter producing 220 would have little problems starting a well pump.

Another solution is to disable the throttle function of the inverter.

 

[CobyRupert]

Even without considering the inverter aspect of it, sizing a generator for a starting motor can be tricky. Go big and don't worry about it. But when you're cutting it close a lot comes into play.
Motor side : 1) Inrush of motor: For a given horsepower, different types of motors will have different inrush. (Example: A high efficiency motor will have a higher inrush than a standard motor.)
2) A variable torque or constant torque load. Being a pump, the mechanical (water) resistance is near zero when it starts (vs. say a rock crusher where there's immediate torque required at start up.
Generator side: Things that can vary from one-brand to another: 1) There's a flywheel effect of the genny's rotor and motor that will help overcome starting surge.
2) The responsive-ness of the governor to react can vary.
3) The fuel type (gas, natural gas, diesel?) The different power-torque curve of each type of engine will respond differently to overcoming starting surge.
Most (bigger) generator manufacturer's have free software or a website that (if you know your load(s)) can calculate voltage dips (or voltage crash!) at startup.
The starting sequence of your loads can also effect if generator sizing. Example (making up numbers here) a 100 amp genny might be able start a 50 amp motor and then run (3)- 10 amp loads. But if those (3) 10 amp loads are already running, it won't be able to start the 50 amp motor because of the starting inrush. This is important to know if a bigger load (like a pump) is cycling on and off.

 

[HEC]

Even without considering the inverter aspect of it, sizing a generator for a starting motor can be tricky. Go big and don't worry about it. But when you're cutting it close a lot comes into play.
Motor side : 1) Inrush of motor: For a given horsepower, different types of motors will have different inrush. (Example: A high efficiency motor will have a higher inrush than a standard motor.)
2) A variable torque or constant torque load. Being a pump, the mechanical (water) resistance is near zero when it starts (vs. say a rock crusher where there's immediate torque required at start up.
Generator side: Things that can vary from one-brand to another: 1) There's a flywheel effect of the genny's rotor and motor that will help overcome starting surge.
2) The responsive-ness of the governor to react can vary.
3) The fuel type (gas, natural gas, diesel?) The different power-torque curve of each type of engine will respond differently to overcoming starting surge.
Most (bigger) generator manufacturer's have free software or a website that (if you know your load(s)) can calculate voltage dips (or voltage crash!) at startup.
The starting sequence of your loads can also effect if generator sizing. Example (making up numbers here) a 100 amp genny might be able start a 50 amp motor and then run (3)- 10 amp loads. But if those (3) 10 amp loads are already running, it won't be able to start the 50 amp motor because of the starting inrush. This is important to know if a bigger load (like a pump) is cycling on and off.

Very well said ----I have an old 5000 watt gas gen. and was trying to run a 220 pump and my boiler at the same time and ended up replacing both the well pump and boiler motor shortly there after . I can only guess it was the gen. as it was really luging down when they both would run at the same time . Lesson learned the hard way .

 

[Tig]

We've been through some extended outages and I dislike more than just the noise of a generator. But reality is, I need water and a hot shower sure hits the spot. I bought a 9000W surge, 7200W running, generator. It's not quiet by any means, but it runs my pump and HW tank at the same time at 65% of it's rated running capacity. I use it as required. A couple hours in the morning, same in the evening. Just enough to keep us fed, clean and the freezers frozen.
I have DC backup for my home office electronics and I have even acquired a DC water pump which I will try to use to draw water from my shallow well. The less I can use the generator, the better.

Edit: It's also been my experience that generators are hard on the switches that control motors. Arcing will burn them out given a chance. This may be a phenomena of cheap or somewhat defective generators, but in any case it plays to my less use is better philosophy.

 

[IXLR8]

I have solar panels for hot water, propane for cook stove and wood stove for heat. My two big draws are the refrigerator and the 1/3 hp well pump. I have 3 neighbors who are running 3600 rpm generators.... we are getting really tired of listening to them. I wanted to get an inverter generator so I was not adding to the noise and they are much more efficient and longer lasting.

 

[IXLR8]

Very well said ----I have an old 5000 watt gas gen. and was trying to run a 220 pump and my boiler at the same time and ended up replacing both the well pump and boiler motor shortly there after . I can only guess it was the gen. as it was really luging down when they both would run at the same time . Lesson learned the hard way .

This is exactly what I am afraid of.... will an idling inverter generator be able provide the power a well pump starting up will need with out messing up the motor.

 

[HEC]

I recently bought a 1500 watt gen. from tractor supply to just run my now coal boiler . It is not to loud , doesn't use to much fuel and did a good job of runing the coal boiler during this power outage we just had .The coal boiler doesn't use much power but does use some sensitive equipment . I am quite confident it would run an oil boiler also not sure about a furnace with the blower and all .

 

[Tig]

Nice set up Jim.
Based on the following estimate I found online, I think you could get away with a 3500W (running) inverter generator.
Well pump 1/3 HP, 750W running and 1500 startup.
Refrigerator, 700W running and 2200W startup.

Edit: 4000W would be preferable, but I've not seen that size in a portable inverter generator for a reasonable price.

 

[IXLR8]

Tig- Thanks for the input, I am considering one of these two. As far as I am conserned, no inverter generator is reasonably priced.

Yamaha EF4500iSE - 4000 Watt Electric Start Inverter Generator. $3100
OOP's- This Yamaha is only 120vac, I need 220vac for the well pump so
I will have to look at this one.
Yamaha EF6300iSDE - 5500 Watt Electric Start Inverter Generator. $3700

Honda EM5000iS - 4500 Watt Electric Start Portable Inverter Generator. $3700