Motor contactor chatter...

[Twodose]

Replaced all the motor contactors in my 3 bay carwash about 4 or 5 years ago with LC1D18B7 and the LRD21 by Telemecanique.

Last weekend when it was very busy on the high pressure, one bay (the least used one) stopped then started then stopped and started again within a couple seconds.

The next day it was chattering off and on and you could see sparks flying inside the contactor, so first thing I did was check the 24v and that was OK, so I changed the contactor and motor protector and everything seems to be fine. Brought the contactor home and hooked up to 24v and it worked fine, it went in and stayed in and when unplugged stayed out.

Was wondering if it could be a voltage drop from a bad timer or something else.

Any ideas what may have caused this, or is it just a bad 24v coil?

 

[MEP001]

I would check all the wiring connections from the timer through the switch to the contactor.

 

[cantbreak80]

Last weekend when it was very busy on the high pressure, one bay (the least used one) stopped then started then stopped and started again within a couple seconds.

That blows a big 'ole hole in my theory about never having to fix things that don't get used!

 

[2Biz]

Were you able to check the 24v at the same time it was chattering at the CW?

 

[Twodose]

Were you able to check the 24v at the same time it was chattering at the CW?

No i did not. It was chattering so bad, sparks were flying and the motor was banging on and off, i was afraid it would do major damage.

If i pushed the coil in with a screwdriver it would work fine, I'm talking no power just pushing in the coil manually.

 

[cantbreak80]

Hmmmm,
"Least used bay"...furthest from starter panel???
Measure voltage at meter box...24+ volts?
Yes...swap timer from working bay
No...measure voltage at transformer...24+ volts?
Yes...MEP001's suggestion
No...replace transformer

(I'm betting it's the timer)

 

[Twodose]

Timers inside the ER they are gs-401.

Thing is it worked ok after swapping out the contactor and motor starter.

 

[mjwalsh]

Timers inside the ER they are gs-401.

Thing is it worked ok after swapping out the contactor and motor starter.

Twodose,

We have a large quantity of similar relays on our laundromat washing machines to maintain. We have experienced where similar intermittent chatter was caused by the contacts not seating completely. That also would explain the arcing. The travel from open to closed contacts sometimes can get messed up mechanically.

mike

 

[MEP001]

Thing is it worked ok after swapping out the contactor and motor starter.

The contactor could have a bad coil, the thermal overload could be failing (if it cuts the 24V only to the coil) or you may have had a loose wiring connection that you fixed when you changed it. I would label the parts with the problem you had and set them aside as potential spares, or just toss 'em if you don't have the problem again for a long while.

 

[JIMT]

Twodose,
We had a similar problem. The problem was that the contactor was using the electric conduit as the path for the common wire. We put in a common wire from the electrical panel to the contactor and the problem disappeared. When the contactor engaged the box would move slightly and loose the common connection in the conduit.
JIMT

 

[whitescout]

Have you checked the voltage at the coil for the contactor? In an earlier post I see that you said the 24V checked out fine, but where was this tested? If it was tested at the transformer, the voltage could be dropping by the time it goes from the transformer, to the timer, to the rotary switch, and then back to the contactor.

 

[wash4me]

options

Have you checked the voltage at the coil for the contactor? In an earlier post I see that you said the 24V checked out fine, but where was this tested? If it was tested at the transformer, the voltage could be dropping by the time it goes from the transformer, to the timer, to the rotary switch, and then back to the contactor.

Can you switch the contactor out with another one to see if the problem follows the contactor or the circuit? You can also disassemble the contactor and inspect the contacts. I would just put in a new contactor and overload. If the problem is fixed then great. If it's not then you have a spare.

 

[Twodose]

Can you switch the contactor out with another one to see if the problem follows the contactor or the circuit? You can also disassemble the contactor and inspect the contacts. I would just put in a new contactor and overload. If the problem is fixed then great. If it's not then you have a spare.

I changed the contactor and overload as stated in a previous post, and it works fine.