Home Forums General Discussion Technical Questions 1968 Otis relay logic issues

I am troubleshooting a hydro Otis elevator 4 landings. When the elevator first went down, I found that the 3C coil was fried. I replaced that and now I can't get my 3C to latch. All my other relays latch (1U, 1D, 1C etc) except 3C. Even my 3D and 3U latch, but when any call is latched it stays latched and the elevator goes to the floor and the door stays open. The only way to get the doors to close is to manually open the latched relay. Does anyone have any suggestions? My 2nd floor car button works fine, I checked that. We've checked other coils, cleaned contacts and checked wiring, I just don't know what we're missing. Any idea's would greatly be appreciated.

Check the air gap on the armature of your 3C relay. The armature needs to contact the frame of the relay. If your new coil has plastic caps on the ends and your old coil didn't, remove old shims (non metallic and metallic washers).

For call cancelation, check the common feed for your reset circuit. Are you getting a buck out or reset voltage on any coils. Also, check your door open limit.

Thanks for the advise, I'll check tomorrow.

What sort of relay logic? 2 speed ac or geared umv with selector? Either way NM is correct, it sounds like the reset side of the circuit isn't working. Having more than 1 act like this, it would be from the supply section. Look for the st circuit for the 2sp or up call stop brush, down car stop, or car stop to initiate this floor relay reset.

The culprit was a bad resistor. The new coil I installed was bad also. I'm not sure if the bad resistor damaged the new coil, but I will replace that coil when we replace the resistor. Thanks again for all your help.