[BrentL]

Different things to look for other then pitting.

 

[DavidDeBord]

Such as Arcing? Chattering? Melted casing? Smoke coming from it?

And worse yet, .... Voices screaming "Help Me!"?

 

[BennyD]

Well, there's a bit...
If it buzzes, probably a bad shorting ring. Either new coil or contactor depending on size.
I have seen the retaining springs for the contact bar get weak from age or heat.
If it looks dusty, that's metal dust from the arcing. That NEEDS to be cleaned. Eventually it will arc across tthe legs and blow up. An electrical cleaner and a good brush will take care of it.

Sent from my SM-G920V using Tapatalk

 

[VectorTech]

Different things to look for other then pitting.

Contactors are cheap, if it's burnt and pitted you don't need further diagnosis, it will eventually weld itself shut. Change it out, save a compressor

 

[Answer-Man]

Condition of wire attached, condition of wire insulation, besides other visual items listed. I also check termination tightness, voltage drop, amperage variation, resistance reading, and a good control voltage to the pickup coil

 

[Answer-Man]

I had one last week, one leg was dead, contactors was pulled in, no noise, no discoloration. Could not see the contacts but voltage told the story (no voltage present on load side)

 

[servicefitter]

More than 5 volts across a pole it's replaced

 

[Juan Madera]

Any crud between the coil and the armature that keeps it from pulling completely in will cause a "buzzing" noise and excessive current draw on the coil eventually burning it out.

You cannot buy a good contactor anymore, so I try to keep any of the american made ones as long as possible. Chinese stuff has the life expectancy of a house fly.... If you have a source for contactors NOT made in China, tell me.

And I condemn any dropping 2V or more across T & L under load...

 

[theoldscroll]

Many times I have changed them because the dual cap is bad and make it part of the repair. Takes only a couple more min. to do, people get to feel like they get more for doing it "while you're here", and hey you can charge for the part.
Visual/physical damage or voltage drop/ohm resistance thru the points makes it a must as said before.

 

[DOGBOY]

how about the Emerson Sure Switch? I have put on a couple they seem nice, it monitors line voltage so if it is low it won't close.

 

[Juan Madera]

Three phase sure switch?

 

[Poodle Head Mikey]

1. Doesn't pull in - that's always a bad one.
2. Stays pulled in all the time - that's even worse.
3. It's rusty inside and the magnetic resonance hum keeps somebody up all night - nobody likes that one much.
4. Expensive cars in the driveway - that always indicates At Least a bad contactor. 5. Believing reason number four indicates a bad contractor.

PHM
---------

Different things to look for other then pitting.

 

[Poodle Head Mikey]

Did you check for earwigs?

PHM
--------

I had one last week, one leg was dead, contactors was pulled in, no noise, no discoloration. Could not see the contacts but voltage told the story (no voltage present on load side)

 

[BennyD]

I had one last week, one leg was dead, contactors was pulled in, no noise, no discoloration. Could not see the contacts but voltage told the story (no voltage present on load side)

Had ants do that once. I guess they insulate once they die and dry out! Lol
Didn't have one on me, so I took it apart and cleaned it. That was years ago, haven't heard anything since.

 

[DOGBOY]

Three phase sure switch?

Sorry did not realize we were talking about 3 phase.

 

[Adventuredad]

I had a bad new one.... I learned that Ohms between 12-20 across the low voltage is an indicator that it's good. Otherwise it wont pull in. The one I was testing had 3 if I remember correctly. Was a week old. Has anyone else found this to be true? I had a heck of a time finding that info. I had previously thought any low level of resistance was sufficient.