Contactor problem

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Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
I have a plating company that has a hoist with two lighting contactors to control up and down. In the last three months the down contactor has gone out twice now. The coil is sagging just enough to not allow the other to operate. At first I thought that debris was the problem, now I am not so sure. Any ideas as to what may cause the sagging coil?
 

Smart $

Esteemed Member
Location
Ohio
I have a plating company that has a hoist with two lighting contactors to control up and down. In the last three months the down contactor has gone out twice now. The coil is sagging just enough to not allow the other to operate. At first I thought that debris was the problem, now I am not so sure. Any ideas as to what may cause the sagging coil?
Sagging coil? I'm not sure what that means... the coil when energized does not pull in the contacts, or chatters the contacts?

What does "contactor gone out" mean? I can assume it mean it isn't functioning properly... but why so? Coil burnt up or shorted?

First thought is voltage drop. The circuit has enough voltage for the contactor to pull in, but as soon as the hoist motor is energized the line voltage drops to the point where the contactor drops out. Could be source overload, distance and wire size, motor overload, bad connection, etc., or a combination of any of the preceding.

Why are they using lighting contactors, or are you just calling them that? Are they dual rated for motor loads?
 

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
The coil does not return to the fully open position which does not allow the second contactor to close.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Is this (2) contactors or a reversing starter?
What enclosure is it in?
Where is it located?
 

hurk27

Senior Member
sounds like a bad return spring in the contactor, do they have a mechanical interlock, I have seen some used for hoist go bad all the time, try finding a reversing contactor that has contact interlock, also is the contactor installed in the right orientation, some don't work well sideways or upside down.
 

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
I am going to try and fix the other contactor tomorrow by replacing just the (coil) spring assembly. Hopefully this will work for a while.

I'll check into a reversing contactor. Never heard of it.

The contactors are 18 feet in the air (of course) in a NEMA 1 anclosure. They are mounted on a DIN rail along with the overload facing up.

Here's a wiring diagram of what I have.
PapagoPlatingHoist.jpg
 

hurk27

Senior Member
I am going to try and fix the other contactor tomorrow by replacing just the (coil) spring assembly. Hopefully this will work for a while.

I'll check into a reversing contactor. Never heard of it.

The contactors are 18 feet in the air (of course) in a NEMA 1 anclosure. They are mounted on a DIN rail along with the overload facing up.

Here's a wiring diagram of what I have.
PapagoPlatingHoist.jpg

If that is the diagram then you do have a reversing contactor with contact type interlocks see the terminals A1 and 21, you stated lighting contactors in the OP, and yes they can look like one sometimes, these should have motor rated contacts although maybe not the best spring return design, you might be able to find a cross number for a manufacture that is better made, such as an A&B or Square D of the same nema size and style that might fit right back in place of these, I have done this many times where a manufacture used some off brand or other low cost contactor only to have a problem like this, also make sure coil voltage is correct as over voltage can slam the armature hard and break the spring also, for the best I have always used Allen Bradly, but I think the Square D stuff has come around allot lately, while I'm still not real keen of the ICC type relays and contactors, we get allot of that type in our controls panels for lift stations, it is smaller in size, and make the overall size of the cabinets smaller, I just see to to many failures with them, I have a job right now on a brand new install where a ICC electronic overload block melted down when a limit wasn't set right, and a vent motor bottomed out, and were waiting for the factory to send a replacement under warranty.
 

Smart $

Esteemed Member
Location
Ohio
...Here's a wiring diagram of what I have.
PapagoPlatingHoist.jpg
Your diagam only shows a change in the contact order... which doesn't reverse the motor. You have to reverse the line to load order for the two contactors. You reversed the line order... but you also reversed the load order in the same manner. Reverse one or the other, but not both.
 

hurk27

Senior Member
Your diagram only shows a change in the contact order... which doesn't reverse the motor. You have to reverse the line to load order for the two contactors. You reversed the line order... but you also reversed the load order in the same manner. Reverse one or the other, but not both.

Wow How did I miss that, you are correct the rotation is still the same from either contactor., I was to busy looking at the axillary contacts lol,
 
Last edited:

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
Okay, so I got lazy and just cut, pasted and flipped the line side drawing. Here I corrected it.

PapagoPlatingHoist-1.jpg


They are two Telemecanique LC1D18G7 contactors with an LAD9R1V reversing kit.

So I get there and the lid of the j-box holding all of this is open. Contactor is dirty with debris and not allowing the coil to return to the fully open position. Of course, the interlock then doesn't allow the other contactor to activiate. I replaced the contactor with one I had already cleaned. Told them they need a NEMA 4X box because of all the debris that floats around.

Charged, blessed and released. ;)
 
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