120/230V Pool Pump Motor Starting Circuit Shuddering

[ibanezsvo]

My pool pump motor blew the starting capacitor last week and I replaced the capacitor today with one of the same rating. The motor starts and runs fine under no load but once it starts to prime the water and take on load, the starter circuit starts cutting in and out. Any help would be appreciated.
See youtube video:

http://youtu.be/N3SOfhxiypI

 

[Skogsgurra]

Sounds like the motor slows down when loaded. It really shouldn't but if head or flow is high and your motor is marginal, it will do this. Try reducing flow and se if that helps. Or have someone have a look at it. Or get a new motor.

It may also be possible to (re)adjust the centrifugal switch so it tolerates lower speed before switching in the capacitor.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[ibanezsvo]

Ok. Thanks. I was suspecting that the motor has deteriorated but I wanted to get some other opinions before I turned it into s shop.

 

[flexoprinting]

Is there anything other than the load mechanically slowing or binding the motor? a bad bearing perhaps, if it's a bearing that would be a cheap fix. I don't think you want to run the motor slower than rated speed it's just not healthy.

Chuck

 

[flandrax]

It could possibly be that the run winding is somehow not in the circuit. When the motor is first applied with power, the electrolytic capacitor (the one that was bad and replaced), the stationary switch (white looking device in the center of the video), and the start winding are in the circuit with the run winding. After the motor shaft begins to rotate, the governor (the metallic device that the switch sits on) slings in by centrifugal force causing the switch contacts to go open and the electrolytic capacitor is now out of the circuit (no current flow). If the run winding is not in the circuit the motor would start but as soon as governor slings in there would be no current flow to the motor,due to both windings being open, the motor would slow down causing the governor to return back to its original state causing the switch to close and capacitor to once again return to circuit of the starting winding and the motor would begin to accelerate again. If you continue to run this motor like it is you will either blow the capacitor again and/or damage the switch in the process due to the continuous cycling of the switch.

Just two thoughts come to mind either the run winding is not in the circuit or possibly the run capacitor (the capacitor that is under the cover on top of the motor) is bad. Checking the run capacitor would be the easiest to look at before sending in for repair.

If the run winding is open you might check to make sure that there is a circuit through both sides of the overload(the black device that should be above the switch/governor)

 

[waross]

The motor needs both the main winding and the starting winding to start. If either winding is not energized the motor will not start.
It sounds like excess flow or mechanical problems in the pump. A thrust bearing may have failed and is causing a drag when the pump starts working.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ibanezsvo]

Since the load hasn't changed from before and after, I'm going to start with flandrax' theory and investigate the start capacitor. I'll run a test to calculate it's capacitance and post back to let you all know. Otherwise the motor will have to goto a shop for the bearing and what not

 

[ibanezsvo]

typo edit: start capacitor *Run capacitor