Irrigation pump will not stay running

[Capt. Lenny]

I have a Goulds GT10 irrigation pump that's used for watering the landscaping. The pump is controlled by an Orbit 4 station control #57894 and an Orbit pump start relay #57009-PS2. When the timer tell the pump to turn on, it only runs for about 10 seconds then trips the pump breaker. I'm not sure where to start but since the pump starts, I've ruled out the start capacitor and any kind of blockage, the pump turns free. Need some tips where to start.

 

[Valveman]

The pump start relay could be only letting half power through. Low voltage will cause that problem. But it usually trips the overload in the motor first. A tripped breaker may indicate the motor or something is shorted.

 

[Sponsor]

 

[WorthFlorida]

If this is a 230v motor setup, Valveman is probably correct. The pump start relay is a single throw double contact. One set of contacts are probably burned causing a voltage drop. If the contacts were burned open, the motor would not run at all with a 230v setup.

If you are careful and know your electricity, you can bypass the relay. Turn off the power, connect the L1in to the L1out. The same for L2in to L2out. Turn on the power. If the pump runs and doesn't trip out, it's the relay. If it shuts down, the motor is probably bad.

No long ago, I replaced the start cap inside a pool pump motor at my son's house. Not realizing it, I snaked one wire wrong and the wire was nicked by the centrifugal switch and shorted the wire to ground. It burned out the motor.

 

[Capt. Lenny]

Okay here's what I've found. The motor and relay are both 120v. I wired the motor direct to the breaker and the same thing happens. Motor starts and runs for about 10 seconds then trips the breaker. Seems like the motor starts but is somewhat slow getting up to speed. Just doesn't seem to have as quick of a ramp up that I think I remember. Any thoughts what to check first? Thanks

 

[WorthFlorida]

If you have a clamp amp meter, you can check the current draw. On the label of the motor it will read the current draw. It probably is over drawing current and it will trip the breaker, therefore, it seems to be a bad motor.

 

[Capt. Lenny]

Don't have a clamp meter but I'm thinking the motor probably went bad.

 

[Valveman]

Doesn't start up like it should could be just a starting capacitor?