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Contactor not latching

A

An Buachaillín Bán

Hi all.

Is it too early to wish everyone a happy Christmas?😅

Looking for a little bit of help regarding a contactor.

I got a call to look at a 230v heavy duty mixer/blender in a busy hospital kitchen. It has stop/start buttons and a contactor within the appliance itself. Contactor is a Teco, 3 pole normally open. When I arrived I assumed it was the contactor. Start button wasn't energising the coil. It just seemed the start button wasn't working. I checked it for continuity by pressing it and testing the contactor. All was good in that respect with the start button and also the stop button. When I manually engaged the contactor the appliance ran away fine.

I replaced the contactor, but still nothing. The power side of the contactor seems OK. I have voltage. Just wondering if anyone knows what the issue could be. I replaced the wiring like for like to the née contactor. And the appliance was operating fine all along, with me being the first person to open it up.

I've attached a picture. Not sure it'll help. I have control cables at no.22 of my NC end but nothing in no.21 NC. Is that normal?

Thanks in advance.
1000057461.jpg
 
are you getting voltage to the coil when you press the start button?

also, it would be normal to use a N/O contact for the hold in loop, are you sure the contactor is a direct replacement?
 
James said:
are you getting voltage to the coil when you press the start button?

also, it would be normal to use a N/O contact for the hold in loop, are you sure the contactor is a direct replacement?
Click to expand...
Thanks for the reply. I tested across.my A1 and A2 and didn't get voltage reading there when pressing start button.

I also thought that it would've been a normally open contact, but as sure as day it was a NO contactor that I removed. Exact replacement.
 
An Buachaillín Bán said:
Thanks for the reply. I tested across.my A1 and A2 and didn't get voltage reading there when pressing start button.

I also thought that it would've been a normally open contact, but as sure as day it was a NO contactor that I removed. Exact replacement.
Click to expand...
But you have put a n/c contactor in. (1 contact only)
 
21 and 22 is NC that wouldn't normally be the case for DOL control. Are you sure someone else hasn't fiddled with it.
What would happen if it is NC instead of NO it would be permanently on but you say there is nothing in 21.
 
Last edited:
westward10 said:
21 and 22 is NC that wouldn't normally be the case for DOL control. Are you sure someone else hasn't fiddled with it.
What would happen if it is NC instead of NO it would be permanently on but you say there is nothing in 21.
Click to expand...
Yes that's right, nothing in 21. I'll add that there was a second heavy duty mixer/blender right next to this one, which is working fine. So I decided to open it up to check if contactor was NC also, but it wasn't! That's why I'm so confused.

I asked the chef if anyone had been in to repair it. And he categorically stated no. I asked the head of facilitates also, and he didn't organise for anyone else to call in. The had a temporary power cut one day about 2 weeks ago, and the blender never worked after that.
 
I assume the other contactor has terminals 13 and 14 for the auxiliary which would be NO. If the machines are identical including the starter someone has almost certainly messed with it so either suggest you match the contactor from the other machine and copy how it was wired or switch the contactor to try it in the non working machine to test it.
 
If it's a commercial mixer there will almost certainly be a safety interlock on the head, if it hinges or on the bowl guard if there is one.
The interlock will be in the control circuit for the contactor.
What you shouldn't be able to do is get your hands / fingers anywhere near any moving parts when it's running.
 
westward10 said:
I assume the other contactor has terminals 13 and 14 for the auxiliary which would be NO. If the machines are identical including the starter someone has almost certainly messed with it so either suggest you match the contactor from the other machine and copy how it was wired or switch the contactor to try it in the non working machine to test it.
Click to expand...
Yes I just checked the auxiliary terminals and they are 13 and 14, NO. Machines arent identical but this 2nd one has a stop and start button. I'm going to try a NO contactor and will let you all know how it goes.
 
snowhead said:
If it's a commercial mixer there will almost certainly be a safety interlock on the head, if it hinges or on the bowl guard if there is one.
The interlock will be in the control circuit for the contactor.
What you shouldn't be able to do is get your hands / fingers anywhere near any moving parts when it's running.
Click to expand...
Ok, sorry if I'm confusing matters.

I'm getting 152v across 1L1 to 2T1,
1L1 to 4T2 and 1L1 to 6T3.

Should I not be getting voltage across the respective contacts, ie 1L1 to T1, 3L2 to T2, L3 to T3?
 
You should get continuity across them when it is latched closed.
 
snowhead said:
If it's a commercial mixer there will almost certainly be a safety interlock on the head, if it hinges or on the bowl guard if there is one.
The interlock will be in the control circuit for the contactor.
What you shouldn't be able to do is get your hands / fingers anywhere near any moving parts when it's running.
Click to expand...
Indeed. there could be more than one safety interlock - example bowl height and then blender guard.

More information needed. When you don't know the answer - gather more data

Edit: just seen the post where the original poster mentions the difference is this machine has a stop / start.
Excuse this question to original poster, because I do not know anyone here, how familiar are you with DOL starters and auxillary contacts?
 
Late to the party on this one as well, but if the original contactor had a NC auxiliary contact and the circuit is single phase, then one of the main contacts has been used as the aux to hold the contactor on, and as already said, the fault will probably be with a safety circuit external to the contactor.
I'd be getting a pen and some paper and tracing out the circuit of a) what I have with the faulty machine, and b) what it should be, from the adjacent, working, and hopefully, unmolested machine, if it is identical.
 
Good point they may well have put the control through a main contact.
 

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A

An Buachaillín Bán

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Contactor not latching
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An Buachaillín Bán,
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