I think I have a burned out relay

Yes you have a bad connection somewhere in there, some of those terminals look positively nasty with corrosion and dirt
You can start by probing the transformer but I suspect the fault is somewhere else
See if you can locate any loose wires or screw terminals first- you may find a wire that pulls right out of it's lug
A voltmeter could be used to go point by point and track down the failure, but I've often located faults like this by just wiggling wires (with an insulated stick, and gloves)

-M
 
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Eremius said:
I put my meter on it hit the start button and it started up. The voltage to the coil was jumping all over the place and the coil was dropping out/coming on quickly for a few seconds (15-30 ish) then the voltage straightened up at 127v and no more coil chatter.

Next stop, metering out the transformer?
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Based on this comment, I would highly suspect either a bad connection or bad auxiliary contacts in the holding circuit.

Ted
 
talvare said:
Based on this comment, I would highly suspect either a bad connection or bad auxiliary contacts in the holding circuit.

Ted
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I have filed the contacts on the stop button. I am unsure what relay I should be checking out for the holding circuit.
 
Eremius said:
I have filed the contacts on the stop button. I am unsure what relay I should be checking out for the holding circuit.
Click to expand...

The holding circuit contacts are represented as the "M" contact in your schematic. Very likely that those are the contact at the top right hand side of your mag starter.

Ted
 
The "M" coil on the starter looks B-A-D in the photo. It has been severely overheared at some point in the past. So I would venture to guess that there is something external that has caused the overheating. There is also the possibility that something (rust?) is causing the armature (moving contact carrier) to drag. That will generate high heat and coil failure. The coil is rated for 120 volts, check the control power is within 10% of that value and hang a 120 volt lamp in parallel with the coil. That should give an indication when (if) the coil is dropping out. Many cases troubleshooting controls, a lamp is as good as or better than a meter.

It is bad practice to run a machine with the overloads bypassed. It is often done short term for troubleshooting. I did such at age 17 at the CG school in 1968, blew out power for the whole end of the building. Memory digression there. . . The overloads are there to protect the much more expensive motor. They should be kept functional. Heaters are sized to motor full load amps.(FLA)

Attempt to (unplugged) lift the contacts into place, the armature will be tight but must be smooth. If there is dirt in the magnetics, it will cause severe heat in the coil if it doesn't seat properly.

I didn't see any signs of burnt wires in the photos, except around the starter coil. I would concentrate there, but don't wear blinders. Also, there is nothing in the photos to cause much heat. Watch/check for something warm. But change that "M" coil right away. If it isn't causing the trouble, it certainly is interfering with operation.

.
 
In post #7 the coil voltage was found to be jumping around so even though the coil may look suspicious, it's apparently OK
The voltage to the coil is intermittent due to a bad connection or crimp lug, we think. Could even be a faulty transformer. The OP was going to monitor it when the fault occurs but we haven't heard the result of that test yet. Tracking intermittents can be very time consuming-ask any mechanic or tech
-M
 
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What kind of machine are we dealing with here?
Post a picture of the tag on your motor.
I see your in Michigan. I probably have a good used contactor with overloads.......if you pay for shipping
 
Do you know the history of the machine? If it's a 3 phase machine it's likely it could be wired either 220V or 440V. If it was originally wired 440 and is now running on 220 it's likely the overloads (heaters) are too small. I had a similar problem with a Bridgeport. It was originally run on 440 and later changed over to 220. It would run a few minutes, or sometimes only a few seconds then quit. A little investigation found whoever changed over the wiring hadn't replaced the overloads. At 220V the overloads were undersized and couldn't handle the current.

I would also check the coils for the contactors. If they're 440 coils they likely won't pull in or hold the contactors when run on 220 volts.
 
It is wired for 220V single phase. Take a look at the first image.

There are three things that I think could cause this coil to not stay engaged, but I hate trying to diagnose electrical issues without being there and without specifics about the components.

1) Bad connection between the power source and the coil. Test the voltage at each of these points. Also all the connections between the coil and the switch.
2) The coil is worn out. They only have so many cycles in them and every time it is activated, make or break, those contacts spark and weaken the connection.
3) I don't know if the motor starter has heaters or some other type of overload protection. But those again have a limited life to them. If that is the case, they are relatively inexpensive to replace. For a reference the reset button there is most likely tied to them.

You can do a little research using the Manufacturer and the part number and learn a great deal about the motor starter that could help you here. Most likely there is a manual online, possibly from the manufacturer or other users, that could also have a trouble shooting guide that could help
 
Take the wires off the coil. Wire in a pigtail that you can plug into a wall to energize the coil with the coil energized use your meter to check the far right set of contacts on the motor starter. These appear to be the latch circuit. A latch circuit is what holds the contactor on when the on push button is not depressed.
 
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