2 speed pump trips breaker

[NEPApoolguy]

Hi....I have a Hayward Max-Flo II 2 speed pump that trips the breaker instantly when turned on....I have 250 volts between the common and high speed wires during high speed operation....but also have about 70 volts between the common and low speed wires....this is when it's in high speed.....when I switch the speeds....i still have approximately 70 volts applied to the pumps windings that aren't being used....is this normal....not sure if it is....reason for asking is because I've burned up 2 pumps in less than a year....I didn't do the electrical...the labels on the outside of the motor are burnt....like if the motor is getting extremely hot....any ideas???

[drband]

Does not sound good. Some folks on the forum have pump wiring expertise and may be able to help. From you report, it sounds like there is a wiring fault in either the supply lines or even the terminal block on the pump itself. I did wire my own 2 speed but did not run into the problem you state. Maybe time to call an electrician.

[BigDave]

I agree with drband - this is not good. Kinda sound like you might have a neutral and hot leg crossed. Is it fed from a GFCI breaker? Anything else on the circuit? Was this installed by a licensed electrician? Is the pump attached via a power cord or hard-wired? Is there a control system of any type on the same circuit?

Best bet - find a different electrician, licensed with pool experience.

[NEPApoolguy]

Thanks for the replies...its not actually my pool...but a customers...in order to read the voltages....I had to disconnect the wires from the pump itself....cause otherwise it trips the breaker instantly....so I dont believe its the terminal block on the pump....that seems to be ok....the customer bought a pentair control system with a 2 speed relay and installed the system himself....he claims that the 70 volts applied to the not used windings shouldn't be a problem....I think differently....customer claims the pentair system is 100% wired correctly.....guess we'll have to check....my question was the 70 volts....sounds like the above post agree with me....by the way....this customer claims to be an electrical engineer.

[BigDave]

Electrical theory and the trade practice of Electricians are different and often not mutually understood. Power Systems Engineers should understand that unbalanced loads and neutral faults and opens (in the customer premises as well as the mains and distribution networks) can cause unexpected voltages on neutral and lines. Neutral should be connected to Ground at the service entrance panel so voltage on the power company neutral could be seen on the Ground line.

I'd want to know what the line to line and line to ground voltages are on this circuit with the control system disconnected.

Bottom line - something's wrong. A good Electrician with pool experience should be able to help.

[Watermom]

I'm going to ask Poconos to take a look at this thread for you.