IDEC RTE timers

[G2T2]

Throwing a hail marry here. We have been using IDEC RTE timers for decades at our plant. Specifically RTE-P1AF20 and RTE-B2AF20. We recently built a new MCC/ transformers as part of expansion. Inside MCC we are using IDECs for some controls and noticed intermittent failure of RTE relays shortly after commissioning. Upon further investigation we found the same failed relays work perfectly outside of the new MCC. After checking all voltages [120vac] and switches everything seemed to be in order. In a last ditch effort we ran a separate 120vac circuit from a different, close by MCC and everything at that point worked perfectly. Currently, one month later, testing of relays in new MCC they appear to be working properly. Currently have our electrical contractor doing some power quality studies. Has anyone seen this situation before?

 

[jtn]

Just throwing darts, but sometimes the neutral wire is the problem and not the power wire. Something that is often overlooked!

 

[I_Automation]

Just throwing darts, but sometimes the neutral wire is the problem and not the power wire. Something that is often overlooked!

I can second that.



I had a customer that bought a used processing line and in a bank of about 30 CR's 4 of them never worked. All the coils were getting +24VDC, replaced relays and sockets - still not working.


Finally checked the 24V across the relay coil terminals (always before put the COM lead on the terminal block nearby) and suddenly 0V.


Turns out the Common wire was daisy chained through all the relays, but jumped over those 4. Those 4 had common wires, but only between themselves. Cut the long bypassing wire & put it on the 2 end relays and now they all worked.


No idea how long it had been run like that but for normal operation of the line those 4 relays would have had to been on when needed.

 

[G2T2]

I agree that makes sense and am walking the circuit back to its origination point wire by wire and every connection in between. The confusing part was that at the time of fail all the voltages measured correct. We even tested other out of the box IDECs in wall outlets in the new MCC to have them fail there as well. That's when the decision was made to grab a circuit from another area. Only the IDEC timers seem affected all other PLC, relays and motor controls seem fine. More recent testing with the IDECs relays has been successful. Appreciate the thoughts so far.

 

[I_Automation]

Only the IDEC timers seem affected all other PLC, relays and motor controls seem fine.

I have a saying that may apply here:


Dirty power can do wondrous things

Put a line filter on the AC power after the transformer.



I have worked on machines that gave weird things - even had a laptop that told me the battery needed replaced and would not charge it. Then when I plugged in the USB UIC for a SLC PLC I got a Last USB Device Connected Failed popup. When I went to the office to get another laptop and UIC I plugged in the defective laptop out of habit and now it showed 99% battery and charging fine. Then plugged the UIC in and it popped up in Device Manager fine.


Took them back to the line and this time didn't plug into the programmer port in the enclosure and everything was OK. After I was done I unplugged from the wall outlet and plugged into the enclosure power and suddenly the battery was dead and the UIC shut down. Got a line filter and put it in after the transformer and no problems since.



This line also was having PLC and HMI failures that needed replaced too often before the line filter. This line had ultrasonic generators and the line next to it had a rack of electroplating high frequency rectifiers.

 

[G2T2]

This is what our contractor is having us try, Phoenix Contact Uninterruptible power supply - QUINT4-UPS/1AC/1AC/1KVA. Waiting for an outage to swap it over... I am hopeful. Inside this new MCC is even a clean power transformer [new to us]. We are even thinking of changing it.

 

[I_Automation]

On another dirty power issue I recently had a stamping press that one of the DeviceNet IO modules shut down communicating.


Turns out one of the modules in a remote enclosure a while ago lost the 24V power through the DeviceNet cable so they tied the power to a local 24V power supply in that enclosure to it to get it running. They then thought to prevent future Devicenet wire breaks from doing the same thing they did this in 3 other remote enclosures too.


The one that shut down was one of the other enclosures and when the power from the 24V power supply was removed the DeviceNet comm's restarted OK. That local power supply was kicking out dirty DC power, replaced it and now if the 24V is connected the comm's are still good, but I left it disconnected and suggested the DeviceNet cable to the problem one be replaced.

 

[G2T2]

Good info. You're confirming some of the issues I am seeing here. I'm keeping a some what close Eye on this mcc, thinking "OK what's next"