GE 24v Lighting Troubleshoot

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Cory V.

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St. Louis, MO
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Construction Manager
I need help from someone who is familiar with a 1970's GE 24v relay lighting system. The guy that owned the house I live in before me was an electrical engineer and seemed to go crazy with this stuff and I am having one hell of a time troubleshooting this issue I have.

the issue: I have one lighting circuit that will not turn off. It all of a sudden started doing this. I checked all the switches that work this circuit and they are good. I switched out the relay (2x) with a new one and that did not fix it. Everything else in the house works except for this one. I have spent hours upon hours trying to figure it out and I am at a loss.

Any suggestions?

thx
 
Little Bill

Little Bill

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I'm allowing this thread as it is only a question about the system. Please keep all replies to only the system and no wiring or other electrical "how tos".
 
synchro

synchro

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Chicago, IL
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EE
The link below has some information about GE's low voltage lighting control system.
Note that it utilizes latching relays. One coil winding is used to turn the relay ON if it's in the OFF state. Another coil winding is used to turn the relay OFF if it's in the ON state. Separate ON and OFF momentary switches are needed to activate the respective coil windings in the relay.
And so a light switch must be closed (at least temporarily) in order to turn off a light, instead of a switch being opened as in common lighting circuits.

 
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g-and-h_electric

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northern illinois
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supervising electrician
Real quick thought here.... IF the relay is going on and off like we think, has the OP isolated out the line and load from the contacts, and verified that they are opening and closing.... if that is the case, the problem lies outside the lovo control system.

Also isolating the load would show if there is another fault on the circuit that is causing the load to stay on......


Howard
 
Fred B

Fred B

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Upstate, NY
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Electrician
Cory V. said:
I need help from someone who is familiar with a 1970's GE 24v relay lighting system. The guy that owned the house I live in before me was an electrical engineer and seemed to go crazy with this stuff and I am having one hell of a time troubleshooting this issue I have.

the issue: I have one lighting circuit that will not turn off. It all of a sudden started doing this. I checked all the switches that work this circuit and they are good. I switched out the relay (2x) with a new one and that did not fix it. Everything else in the house works except for this one. I have spent hours upon hours trying to figure it out and I am at a loss.

Any suggestions?

thx
Click to expand...

Any other electrical work recently done on the home? These systems can be quite confusing to the unfamiliar. I've seen where someone had done work on a unrelated circuit that ran thru a common jbox that got interconnected with the controlled circuit causing a neutral backfeeding issue. I've also seen where an issue appeared as result of the "master control" had a fault that basically locked a particular switch from operating. Also the relays will stay in last operated condition if the LV power to the switch is interrupted for any reason (rodent chewed thru LV conductor).
Basically this can become very tricky and best handled by an experienced electrician because it can quickly become a much larger issue as an unknowledgeable person "tinkers" with these system. Those old GE Remote Control (24V relay) are no longer supported and parts hard to find or not available and no OEM parts, and would require major change out of parts, if a tinkerer was to short out a relay or switch. (Switches not available as original configured, and cover plate for the old switches not available, one example.)

Get an experienced electrician in there to trouble shoot issue. Will save a lot of potential costs that would result from improperly messing with the system.
 
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gar

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Location
Ann Arbor, Michigan
Occupation
EE
210412-1011 EDT

I can not quickly determine whether GE or someone else is still making RR-7 relays. There seem to be many available on the Internet. Many grossly overpriced.

The GE RR system is an excellent system for controlling lights and other low current loads, less than 20 A. It has motor switching capability, and I believe is is rated for 240 V.

Only people without a good understanding of electrical circuits have a problem working with these relays. The electrical circuits are really very simple, and you can do some complex switching operations. The relays also cause very little power dissipation when on or off, and at full AC load. They are mechanically bi-stable, and remain in their last set state. I consider them to be much superior to an electronic switch based on a semiconductor.

At 20 A the switch voltage drop across the RR relay will be in the millivolt range. Without doing a test I don't remember if this means less than 20 millivolts or not. In contrast a solid-state relay will likely be above 1 V. This is a big difference in wasted power at the switch point, and how to remove that heat,

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