1) I have a 220V 3 wire submersible pump in my well (30 feet deep)
2) The pressure switch close at 30psi as it is supposed to and the pump begins to run.
3) The pressue rises to about 40psi and the pumps quits for a few seconds and then starts again.
3) The pressure switch remains closed when the pump cuts out.
4) The pressue eventually gets to 55psi and the pressure switch opens
5) What is causing the pump to stop running? Bad pump?

I would start by replacing your pump control box. Please let me know the brand of the pump. Are you sure the pumps stops, or does it just not raise the pressure for a few seconds?

I have repalced the cotrol box and the pressure switch. I replaced the control box because it was hot, there was a little oil in the box and it smelled burn't. The pump quit working altogether and when a replaces the control box it started again.

You make a good point about the pump. I assume it is turning off because the pressue just holds between 40-45psi then goes up a little (a pound or two) and holds again. It the water isn't continuing to run it does this on=off thing twice and then it takes off an goes all the way to 55psi and the pressure switch trips off.

I am pretty sure it is a Wayne pump.

The oil in the control box sounds like an exploded capacitor. Make sure that the new control box is compatible with your pump.
Hope this info help, and please let me know what you find.

Yes I think the capacitor did explode. My wife was washing her car last night and she said "the pump kept cycling on and off". I took this to mean that it was doing the same thing I am seeing now. The cycling on and off must of did the capacitor in. I replaced the control box with a Franklin control box and it isn't getting hot or anything.

I will pull the pump up and see if I can find out what is causing the problem. I have another pump ready just in case I don't find any answers. I will just replace pump.

Thanks for the help!

If your pump is cycling on and off nonstop while water is being run, I would also check the pressure in the pressure tank. Turn pump power off, drain all pressure off system, then put a tire gauge to the schrader valve on the top of the tank(there should be one) It should read between 30 and 40psi.

Think I found the problem. I pulled the pump out and found a couple of the wires with the insulation worn off. One of the wires actually broke with just a little bit of tension. One of the wires had been rubbing against the back check valve also. Since there was only a short piece of wire left in good shape I replace the pump.