220v motor problems 1

[js3081]

I have a 220v single phase motor rated at 3 HP and 1740 RPM. Motor is connected to a small dual piston pump. Pulley ratio is about 3 to 1 to reduce pump speed. When the pump starts to build pressure, motor speed almost stops. Wiring is as follows> T1 to L1/ T2 T3 T8 taped/ T4 T5 to L2. Can anyone help me through a troubleshooting process? Thanks js

 

[gcaudill]

1.) Is the motor rated for single phase operation?
2.) Check with the motor manufacturer or the wiring diagram on the motor to verify the motor lead wiring.
3.) Have you measured the motor amps during the abnormal operating condition? Maybe the motor is simply overloaded. What is the rated motor full load amps for single phase operation?
4.) Have you measured the motor amps during the normal running conditions? Maybe the motor insulation is failed.
5.) What is the duty cycle of the motor? How often is it started?

 

[SteveKW]

A piston pump is a positive displacement pump and can STOP the motor if you do not have any flow (discharge valve shut off)or try to go too high in pressure for the motor to do the job!

Your connections do look correct for 220VAC.

Also check the voltage at the motor leads while she is running!


What's missing is that your not telling me that the motor is "pulsating". Which is what should happen when a single phase motor starts to stall!

Are you positive the belt is not too loose and all you are seeing is the pump slowing down and not the motor?

 

[gcaudill]

Good advice SteveKw. I should have caught the part about the piston pump. I give you a star.