Symptoms of Too Small a Start Capacitor for Submersible Well Pump Motor?

Do you really mean "start capacitor"? A start capacitor would only be used for a fraction of a second until the motor got up to speed and then would be disconnected by either a centrifugal switch or delay timer.

If it is indeed a start capacitor, then whatever is supposed to disconnect it isn't working correctly and that's the real problem.

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Sam,

After posting was told that the 1/3 hp well pump failed some years ago and was replaced with same or similar pump but the original controller box was kept. It is just a basic box with start capacitor, relay and overload device.

When the check valve failed the pump kept cycling and eventually blew the start capacitor. When I had the controller box open also checked the relay which tested OK but was unable to test the overload device becuase did not have the info. Will do some calling and test because it is the only part left to be checked.

Have only run the pump 3-4 times since installed the new capacitor. As mentioned It runs for ~ 1/2 min and pumps ~ 2 1/2 gal water then shuts off. After a few seconds there is a noise. Sounds to me like mechanical contacts, do not know if it is coming from the overload device or relay but am guessing it is the overload device.

Ken

snipped-for-privacy@yahoo.com spake thus:

Yes; probably a thermal cutout switch, I would guess.

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I wouldn't expect them to chatter under normal conditions, so that sounds like a place to begin. The start capacitor should only be in the circuit for an instant - if you put an multimeter on the highest AC range across it, there should only be AC for that short time but when it gets disconnected, there will probably be some DC remaining on it.

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Could it be that the motor pump is seizing. The sequence of events would be something like:

a) The pump tries to get to speed with the capacitor connected. It reaches the operating speed and the startup relay opens.

b) Without the startup cap, since the motor is seizing, the pump starts to lose speed and draws more amperage... thus closing the startup relay again (and the power consumption gets higher too)

c) The pumps gets again to speed. The startup relay opens again, but the motor looses speed and the relay closes again, thus repeating the cycle. (this would explain the relay chatter)

d) Enventually the thermal cutout switch opens because of the excesive current draw.

Do you have an AC ammeter? You should check how many amps is the pump consuming. That should show you if the pump is within it=B4s normal power consumption or not. If the consumption is too high, the motor is seizing.

Other way to test this is replacing the startup relay by a momentary contact push switch, and using an ammeter to monitor the power consumption of the pump. You initially turn on the pump and push the contact switch to make it start. As soon it gets to speed (probably in a second or less) you release the switch, leaving the startup capacitor out of the circuit. Check the amperage, if the pump starts to draw more an more amperage without the capacitor connected, then you will know that the pump is seizing.

Good luck.

Sam, David, and Ismartino

Thanks for the suggestions.

First will try to clear up any misunderstanding. Nothing is "chattering". Will try to be more clear this time. The few times I have run the pump since the check valve failure, blown start capacitor and replacement start capacitor have used this sequence. Turn on pump switch and pump runs for ~ 20 sec and pumps ~ 2 1/2 gals then stops. I turn off the switch and a few seconds later hear a "contact like noise"(like relay contacts either making or breaking).

Specifics This submersible well pump is a RedJacket 1/3 hp 230V single phase 3 wire Model 33 M1. The control box is a "town and country".

After the blown start capacitor the 1st thing done was to check the resistance of the motor windings which were OK. Also checked the relay and it was OK. Since posting was able to get the test value for the Overload Device and it checks OK. Only problem something is wrong since pump stops after ~ 20 sec.

As previously mentioned am guessing it is the overload device. When the pump is running can not hear the relay or overload device activate.

The only Digital MultiMeter I have is a Sears Craftsman Model 82141. Checked AC and it lists 10A. Have never used it for measuring current for a 230V electric motor so will need some hand holding. The specs I could find for the Model 33M1 motor are

Amps normal 5.3 idle 3.5 lock rotor 20

Is there some way I can send the schematics? Or are all single phase

230V pump motors with mech relay, start caps and overload protection the same?

Ken

Without an AC ammeter you can=B4t diagnose what is wrong. You really NEED to know how many AMPS are your pump consuming. I still think the pump has a mechanical problem and it is consuming too much amperage. You need an AC Clamp Ammeter like this one:

Don=B4t *even think* to use your DMM to measure the amperage. The LRA amp rating of the pump are 2 times the maximum amperage supported by your DMM and you can blow the DMM.

lsmartino,

Thanks for the warning and link to Sears Clamp Ammeter!

Update found out that the Overload Protection Part was designed to protect both 115 and 230 Volt pumps. Took it out and everything ran OK. No shutdowns....

The pump repair person who checked the control box when the capacitor blew said the overload device was wired incorrectly so after getting the new cap installed as suggested. Since everything is running OK with the Protection Part removed and the part tests OK am guessing the suggested wiring for it is incorrect for 230 V.

The Overload Protection Part is a Klixon TA5 that is no longer made and Klixon does not have a part that will interchange with it.

Would be interested in any suggestions concerning tracking down correct wiring for it.

Ken

I couldn=B4t find anything by Klixon TA5... aren=B4t there other numbers on the Klixon protector? Even a picture of the protector would be great. Maybe TA5 means 5 Amp... but I=B4m not sure.

If there are other numbers printed on the component, please post them here.