Jacob375r
Have a transfer switch that failed to transfer to gen during a power outage and then back to utility once utility was restored. The contactor assy cycles thru all its positions as it should with power disconnected but once power is dropped out, the generator starts up as it should and then the TS begins to chatter once wire 23 drops out. Wire 23 does not go to zero but it is less that 1 VDC. Voltage on 194 is about 1 VDC less than measured battery voltage. This is all based on what the customer told me over the phone. Wanted an idea of what to be prepared for once I make a visit to the site. The customer doesn't live very close. My opinion is either the controller (Nexus) isn't dropping wire 23 or the ice cube relay is faulty. Thanks in advance of your help.
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Brian Baughman
The transfer signal are control conductors, 23 and 194. The generator controller closes a contact on wire 23 and completes a 12V DC circuit to the ATS for transfer. I bet the control wiring is messed up.
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Peddler
The 23 wire doesn't drop out per say it goes to ground. With the generator running I would, in the transfer switch, Jumper the 23 to the ground and see if it transfers. When you release the ground it should shift back to utility if the utility is connected. OF course you need 240 VAC from the generator for the transfer to occur, less than 240 could cause it to chatter. The 400 amp switches have some micro switches deep inside the transfer mechanism that I have seen give trouble. There is a test procedure for ohming them out which tech support can supply you.
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Birken Vogt
It is curious what is chattering since typical relay chattering is caused by the relay sharing the same power supply as the load it is controlling. This is not the case with RTS so I suspect something a little more involved.
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Jacob375r
What is happening is. wire 23 is grounding out as it should. the contactor then goes thru its sequence and transfers to gen (the movement of the contactor seems weak) then once it is commanded to switch back to utility, the solenoid moves but it dosen't always travel far enough to switch it back to utility. It seems that the mechanism is binding up. I also noticed that not all the fingers behind the arc chutes are making contact with the pads. The xfer assy is pn. 0D7294. Don't see many issues with this type of assy but it looks as if this type of xfer assy is non-serviceable. There are no broken springs and tension on the side lug seems sufficient. The whole system is no more than 10 yrs old, everything is nice and clean with no rust however the gen only has 56 hrs. of run time so it looks to me that the transfer switch hasn't had to work all that often. I just acquired this customer within the last year. The cust had just purchased home at the time and they had no indication of any service or regular maint before the purchase. We perform maint/inspection on it every 4 months and with all my customers we perform a power transfer at least once a year to verify proper operation. There has not been any indication that there were any issues with the switch until recently. Any ideas or just replace the xfer assy? Thanks Everybody!
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Ziller Tech
Can you move the mechanism with the little square shaped manual lever? If so, you may just have a weak coil. The coil can be replaced as well as the PCB in there and the limit switches among other parts. I believe that coil has 2 actual windings in there and maybe one has died?
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Jacob375r
I can ratchet the mechanism. If I can replace the coil, the cust would like me to do that instead of replacing the contactor. However there is still the issue with the fingers of the contactor not making contact with the pad. The one finger that dosen't seat or contact fully is showing evidence of getting hot (blue discoloration).
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cookelec
When you operate the switch manually (using the manual handle) in both normal and emergency, do all the primary contacts close or do they still not fully seat? (Do not do this under load conditions)
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Ziller Tech
That contactor is VERY expensive, so if a coil fixes it, I'd do that. If part of the coil has gone bad and is warped inside, it may be holding the mechanism up. I'd try to remove the coil and see if it can be moved manually and all the contacts seat.
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Jacob375r
They do not fully seat. Specifically the E2 fingers (there are 3 of them) the right hand finger does not contact the pad on its own weather the contactor is moved manually or automatically. It will contact the pad if you push it against the pad (it doesn't take any force to move it).

Again, Thank you to everybody for you engagement and help. Much appreciated!
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Jacob375r
Yeah, @$2,300 or something. That's why I'm checking with you guys on the issue with the fingers before making a decision on replacing the whole assy. The coil may very well be weak but when I cycle the it manually, I do it with some authority. There seams to me that there is more than one issue with the contactor as a whole. The binding seams to be with the selector cams (that's what I want to call them) but it could be with the plastic assy being warped or something. Nothing is cracked or broken and there is no wear that can be seen thru visual inspection without taking the contactor out of the enclosure in fact giving the age of the system, everything could be passed off as new. Of course the assy may have had this biding the whole time and has attributed to the coil weakening?
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Ziller Tech
Jacob375r;52165 wrote:
Yeah, @$2,300 or something. That's why I'm checking with you guys on the issue with the fingers before making a decision on replacing the whole assy. The coil may very well be weak but when I cycle the it manually, I do it with some authority. There seams to me that there is more than one issue with the contactor as a whole. The binding seams to be with the selector cams (that's what I want to call them) but it could be with the plastic assy being warped or something. Nothing is cracked or broken and there is no wear that can be seen thru visual inspection without taking the contactor out of the enclosure in fact giving the age of the system, everything could be passed off as new. Of course the assy may have had this biding the whole time and has attributed to the coil weakening?


Could be. If the contactor mechanism was binding and not closing into place, it would also leave a limit switch hanging and not have the coil shut off. An energized coil will burn up VERY quickly!
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cookelec
If the power contacts are not closing in both modes tightly (with some pressure in the closed direction) in the manual mode, there is something binding in the switch. I don't think replacing the coils will help if the switch is not working manually. The problem with the electrical operation sounds like a result of the mechanical binding.
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Jacob375r
cookelec;52179 wrote:
If the power contacts are not closing in both modes tightly (with some pressure in the closed direction) in the manual mode, there is something binding in the switch. I don't think replacing the coils will help if the switch is not working manually. The problem with the electrical operation sounds like a result of the mechanical binding.


I Agree.
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