I/R SS3 60 gallon compressor start problem

[Ironhead709]

First off,i have been working a lot of OT in thr past year so I have not used this in a while....

And i also did a search and read about possibly being the check valve and/or being too thick of oil in the cold...

I changed the oil today,and it wsa THICK compared to the old,i put the recommended I/R Select synthetic in it,still does the same thing'

The Problem.........

It will "Hum" and either move very slow or not move at all and then trip the motor safety breaker,on the motor itself

I took the belt off completely,turned it on,and......it will still "hum: and move very slow for a few seconds,then kick on and run perfect..this is with no load on it at all,belt completly off...sometimes it will be longer kicking on to full power than other times.
As sort of process of elimination,i put the belt on as loose as it will go,so it would slip and see if the motor kicks on..it did,still with a hum and slow moving,then kick immediatly up to speed,then as it was running,...i tightened the motor up and it ran the compressor pump just like it should...i let it air up to max,it shut off like it should...i pulled the release valve so it would kick on again.....still the same thing...Hum noise,moving slowly and trips the over heat switch on the motor.......

So i am guessing either a capacitor..or i remember someone saying take the front cover off the motor off to clean some contacts?

The motor bearings in the motor seem fine,everything seems smooth and no play in the shaft.

Seems to me,there is something keeping it from kicking to full power right off the bat like i tused to,when it was running fine it never did any kind of slow start like that on the motor,even when it was real cold out and the oil was thick,i've had the belt squeel and compressor going slow,but the motor was at full power..tightening the belt solved that issue,but now i can't even get it to do that.......

Capacitors?..or some kind of contacts inside the motor?

 

[scw1991]

Sounds like a bad motor start capacitor.

 

[C96]

Sounds like a bad motor start capacitor.

↑this↑

 

[Ironhead709]

it has 2 on the motor,,which one do i replace?..one is black,one is aluminum...

 

[redmondjp]

I believe that the motor on this compressor also has the centrifugal start switch which switches the 'start' capacitor out of the circuit when the motor gets up to speed. You have to take the back end off of the motor in order to inspect this switch.

I'd place my $ on this before the start capacitor (which only sees voltage for a half-second or so every time the compressor starts up).

 

[Ironhead709]

I believe that the motor on this compressor also has the centrifugal start switch which switches the 'start' capacitor out of the circuit when the motor gets up to speed. You have to take the back end off of the motor in order to inspect this switch.

I'd place my $ on this before the start capacitor (which only sees voltage for a half-second or so every time the compressor starts up).

This is what i was talking about that i read and seems to make sense...i can watch through the little holes on the back of the motor whn it is humming and going slow,but when it suddenly clicks on full power/speed.i can see a ring or something slide in on the shaft..

I am going to pull the back cover off the motor tomorrow and have a look and clean things up....i read where its best to clean and grease it..should i pick up some sort of electrical grease to do it?

 

[eddiemeddiem]

Does your multimeter have a capacitance function? This makes it real easy to check a cap.

If not, Google how to check appliance or AC capacitors, you can check them with a plain ol' volt-ohm meter.


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[scw1991]

that's the ring mounted centrifugal switch contacts opening due to the flyweights as the motor speeds up.

 

[redmondjp]

So, check centrifugal start switch (for sticking, burnt contacts), check continuity of motor start winding, and check capacitance of motor start capacitor. Somewhere in there is the answer.