For the wiring experts / Generator question

[Kevin54]

I have a portable generator that I would like to use to run a well pump. The well is not currently hooked to the house. Now my question......The generator has a 4 prong plug for 220. The well has only three wires going to it. two hots and a ground. Is it possible to hook the three wires to a four prong plug and if so, what do I do with the fourth prong. Leave it empty? I am guessing the 4 prongs are (2) hots, (1) neutral, and (1) ground.

TIA

 

[Ezzie]

You didn't specify what the voltage of your pump is nor the capacity of your generator. If it has a 4 prong plug it is probably at least a 5000W unit with a 220V 20A twist lock plug. Make sure you know what voltage your pump is before you do the following.

Assuming it is a 220V pump, you do not need the neutral in the 4 prong plug. Wire the two hots (usually black & red or the X & Y designations in the plug) and the green ground (designation G with a green screw terminal in the plug). Ensure your generator is switched to the 220V position and you should be good to go.

 

[mrb]

the generator needs to be really oversized compared to the draw of the motor to be able to start it.

 

[nadogail]

Everything needs to be connected to a common ground in the event that there should be an insulation failure (short circuit).

Assuming ( a dangerous practice ) The center wire on the 3 Prong Plug is the ground, it would be connected on the 4 Prong Plug to the blade with the bump going to the side.

The generator set needs to be connected to ground, see your instruction book. I keep a ground rod in my "what if" collection in case there is no suitable ground when away from my shop.

 

[Kevin54]

You didn't specify what the voltage of your pump is nor the capacity of your generator. If it has a 4 prong plug it is probably at least a 5000W unit with a 220V 20A twist lock plug. Make sure you know what voltage your pump is before you do the following.

Assuming it is a 220V pump, you do not need the neutral in the 4 prong plug. Wire the two hots (usually black & red or the X & Y designations in the plug) and the green ground (designation G with a green screw terminal in the plug). Ensure your generator is switched to the 220V position and you should be good to go.

Sorry about that. Too many things on the old mind today. The well pump is 220, the generator is 5700 watts and the generator has a 30 amp 4 prong twist plug. No switch between the 110 and 220 on the generator. There are (2) 110 plugs and (1) 220 plug

 

[ArthurPE]

what HP is the pump?

 

[Kevin54]

It's a 1/2 horse, 12 gpm, 230v pump. The only paperwork that I have is a sticker on the breaker panel that states "T12-50 Aermotor" which I believe is a Franklin (?) pump

 

[ArthurPE]

1/2 HP should be <1 KW, even with a poor power factor, closer to 500 W

a 5700 W (~7.5 HP) genset has plenty of oomph to start it...as long as it's not loaded up with other stuff...

 

[Kevin54]

Got it done. No load at all on the generator. But wow!!!!!!! The plugs are not the cheapest things. $30 for a plug is kind of steep I thought, but if you don't have one you have to shell it out. I checked at Lowes and our local Ace Hardware and neither had them, so I had to go to the electrical supply house. At least now if the power goes out I can have water. LOL!!! Really my main concern was that the well has not been used in a couple of years and I was worried that the pump may have been frozen up. Hopefully this week I can get power from the main out to it and hooked back up permament. Thanks all for your help.