IBM Relays – Dover Elevators US Elevators

Over the years we find specific parts of elevator systems that are more challenging than others.  This week we will talk about the use of IBM relays in the 1970s by Dover Elevator and US Elevator.  Neither Dover Elevator nor US Elevator are in business any longer.

 

[A fairly common US Elevator with 70 IBM relays of all shapes, sizes and brands that have been used over the years]

[One of the Dover controller versions that utilizes 64 IBM relays]

The biggest challenge we have with the IBM relay is that the internal contacts are very small to see, so it is difficult to tell if the actual relay is working.  If we can't tell, we will be forced to spend time troubleshooting and that's never what a customer wants to hear.

On Wednesday we had a great find with a relay contact that had dropped to short out.  It is very difficult to see, since it is 1/8" difference, so the relay needed to physically be pulled out to look.  Below is a picture which shows how small that difference is.

 Relay tester – There is a relay tester available to assist in the troubleshooting

Replacement parts – There are a few sources where replacement parts can be found.  One is from Thyssen Krupp's parts company, Vertical Express which supplies “direct replacements” to the IBM relay.  Another provider is Adams Elevator which has a replacement relay.  World Electronics sells a solid state replacement relay for the 48VDC versions only.  

You have 4 pole double throw 26 VDC, 4 pole double throw 32 VDC, 4 pole double throw 48 VDC, 4 pole double throw 48 VDC w/diode, 6 pole double throw 48 VDC, 12 pole double throw 48 VDC.  If you are not paying attention, the most common relay is the 4 pole, and can be replaced with the wrong voltage 26vdc, 32vdc or 48vdc.  Some of the relays that are sold and/or used for original installation are not marked very well.  Commonly companies are using relays that are taken from the boneyard when an elevator is modernized.

Take away – While many of the elevators that run on IBM relays are running well the fact is that the controllers are 40-50 years old and the personnel with the domain knowledge to work on these elevator controllers at a high level are fewer and fewer as they retire.  If your building has a platform that relies on IBM relays I would put together a plan with your elevator company to replace the elevator controller.  

If you have any questions or would like additional information feel free to contact me at CraigZ@colleyelevator.com or 630-766-7230 ext. 107.

Also check us out on Instagram @Colleyelevator see what we have been up to.