GE RR series reliability

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gar

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080425-1424 EST

I started construction of my home in 1965 and completed and occupied it in Oct of 66. All switching is done with GE RR-5 or 6 relays. These plug into busbars in gang boxes. There are a total of about 50 to 60 relays. There are no motor loads and probably not over 500 W on any switch. A number of these switch 8 ft Slimline fixtures. The RR-6 relays have auxiliary contacts for pilot light operation. I have a box labeled 1983 that contains failed relays. There are about 8 relays in the box and all are RR-6. These are not all the relays that have failed, but most of them. The relays have failed over the years probably starting in 1983, 17 years from initial installation would be the starting time. Not all failures were related to high useage, and not all are RR-6.

I have never had a failure due to coil burn out. All failures are the result of loss of bi-state ability. Many of these exhibit temperature sensitivity, and thus work sometimes. I believe all failures are to the off state, failure to stay turned on when triggered to on.

I have conjectured that the mechanical stress created from the busbars may have been part of the problem.

Bi-stable relays are a great way to design a control system, and why I chose to use them. I do not consider conventional switching a satisfactory system.

The RR-5 and 6 use a spring contact for termination of the load wiring. This has never proved to be a problem. However, I do not consider it a high reliability connection.

What have you experienced in the reliability of these relays or competitors?

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mdshunk

mdshunk

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I'm a big fan of the GE RR series switching system for one simple reason. It confounds DIY's and some electricians. More work for me.
 
augie47

augie47

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it has been my experience that RR relay systems with a recitfier on the control voltage seem to hold up better. I know the relays will work without the rectifer, but it seems I've replaced more a/c ones than on rectified systems.
 
mdshunk

mdshunk

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augie47 said:
it has been my experience that RR relay systems with a recitfier on the control voltage seem to hold up better. I know the relays will work without the rectifer, but it seems I've replaced more a/c ones than on rectified systems.
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That's very true. I've been buying my rectifiers from Newark Electronics (Newark InOne, now). They're only about a dollar from them, but almost 30 from the supply house for the GE part. I convert most every AC RR system to DC when I service it.
 
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gar

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ultramegabob:

The GE RR relay has a snap blade switch. Mechanically it has two stable states. Microswitches also use snap blades but not as a maintained bi-stable device, but to get rapid make and break at the threshold point.

In the RR relay there are two coils. One to set the snap blade on, and the other to the opposite state. Either the on or off state is maintained without requiring the a coil to be energized. No power consumption except when changing state. The basic control philosophy is that many normally open switches in parallel can control a coil because only a short pulse is required to change state and the last state remains until an opposite change is made.

One could build a system with a stepping switch using a pushbutton to step from one state to the other. But this provides no infrmation at the switching control point of the state being commanded. So from my garage with the RR type system I can turn on the breezway lights, and the house hall lights without being able to see the lights and know their state. Obviously ordinary switching circuits with a single SPST switch have this same capability. But with RR relays I have this same infromation, up is on, from any of an indefinite number of switching control points.

The real advantage of this system is logic. The control logic is simply a power supply, normally about 24 V, and SPDT switches with spring return to center. Because only momentary signals are required to change the relay state and that two coils are used you can put as many wall switches in parallel as you want. Basically a logical OR circuit for on, and another one for OFF. I have 5 places from which I can control my kitchen lights. All this with 3 wires daisy chained from one switch to another or separate runs to the relay gang boxes. I use the separate run approach. All switches have up as on and off as down. Multipoint switching is why I consider this an ideal system.

In the early days, meaning the 60s, GE put out a nice booklet describing the operation of the RR system.

I have never done the following because of lack of time, and priority. One can create a control circuit to program operation of lights or other things. This include any sort of randomization of operation overlaid on some basic pattern. Remote operation is also feasible via phone line.

Recently at the shop my son wanted to control a exhaust fan from more than one point so we put in an RR relay. One switch is at the fan, and another at the normal walk-in door 100 ft away. Simple low voltage wiring. We can easily add one at the office area door. I would like to see the shop lights controlled with RR relays, but it is a big rewiring job.

Some references:
http://www.geindustrial.com/publibrary/checkout/Application and Technical|tlclvrc|PDF
http://www.kele.com/olcat/LC9/RR-7-9.PDF

The above references do a very poor job of describing the basic philosophy of low voltage control of bistable relays. The 40 year old literature was much better. It is no wonder many have trouble working with this type system even though it is basically very simple.

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gar

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Location
Ann Arbor, Michigan
Occupation
EE
080429-1103 EST

Of the failures you have experienced have these always been coil burn out?
Or were any of these the failure mode I experienced?
Have you ever encountered the RR5 and 6 relays?

I think that most individuals in this country lack any understanding of logic. Thus, the DIYs should be confused.

Here is an example of total lack of understanding about radio signals. I had a neighbor a couple years ago that said that it was amazing that her little cellphone could communicate with Hawaii, yet she was always in her backyard using the phone because it had poor signal strength in the house. Even outdoors our signal strength is lucky to be in the 1 to 2 bar range. Apparently she thought the connection was via a radio path from her little phone to the destination phone in Hawaii, but had no idea that the radio path from her phone was just maybe 1.5 to 2 miles.

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