Can the 91 circuit breaker be used with a Z transformer? You can only use (1) 91 per loop of track, correct? My 91 has 3 terminals and works just fine. Would it hurt my Z transformer if I was to hook it up to it? I mean my Z’s all have built in Circuit breakers, but could I use the 91 for extra precautions? Just so it wont trip on the Z and will trip on the 91 instead and cut power to the Z. Also, can the 91 be wired to a 66 whistle controller? And they all must be wired in series, correct? Thanks.
The number 91 circuit breaker was for use with either pre war or post war trains and won’t give you any benefit for todays high tech electronics in the trains.
Which Z transformer are you talking about? The post war Z by Lionel or the modern Z series by MTH? If it is the modern Z-750 or Z-1000 by MTH the 91 circuit breaker won’t give any added protection, the new transformers have a built-in fast acting circuit breaker.
On my layout I am using 10 amp circuit breakers hooked up to the output terminals, A to D, on my post war ZW. The circuit breakers that I have I purchased from Scott’s Odds and Ends. Circuit breakers are always wired in series from the source to the load.
Lee F.
I am talking about the Postwar Lionel Z transformer that is 250 Watts. I do not have any high end electronics. All my trains are prewar or postwar Lionel. I hope this info helps. Thanks.
Because the Z has its single 15-ampere circuit breaker in series with its common, it can be made significantly safer by adding circuit breakers in series with whichever of the outputs (A, B, C, or D) you are using. Those additional breakers should be rated at no more than 15 amperes. However, if you use breakers with lower ratings, you can safely use wire smaller than 14 AWG, specifically 16 AWG with a 10-ampere breaker and 20 AWG with a 5-ampere breaker.
You should not depend on circuit breakers to protect electronics. They are for protecting wiring and your transformer. Use transient-voltage suppressors to protect electronics (if any). Once an electronics-intensive locomotive begins to draw enough current to trip a circuit breaker, however slow or fast, it is already damaged. Slow (thermal) circuit breakers (like the 91) have the advantage that they do not trip on momentary overloads.
The problem I would have with the 91 is that we don’t know what its rating is. Maybe someone else on the forum does.
So, you think it would be okay to use a 91 with my standard gauge trains? The locomotives that I use are the 33, 10E, 380E, 384E, 385E, and 392E. I have 3 electrics and 3 steams. I hooked up the 91 with my cheaper 10E and it worked just fine, did not trip. It did trip when I put the wheels on the middle rail, just to test to see if the light works and that it did trip and cut power. All worked just fine. I have 5 Z transformers running all my standard trains. Also, I use 5 of the 167’s for whistle and direction control. I hope this info helps. I am not sure if all the built in breakers on my Z’s all work just fine. I have never had the breakers tripped on all my Z’s. I hope they all function just fine. I do not wanna try and test to see if they work, too dangerous and could damage my Z’s. My standard trains stay on the track pretty good. Thanks.
Does the 91 with 2 terminal posts hook up the same way as the one with 3 terminal posts?? On my 91 with 3 posts, I only use the A and Low posts. The 91 with 2 posts, it would hook up the same way, using both bottom posts, just like the 91 with 3 posts?? Thanks.
If I have built in circuit breakers in my Z transformers, I do not need any 91 circuit breakers, correct?? The Z’s have a red light for a circuit breaker, if it were to be tripped the red light would go on. Same idea as the 91. Thanks.
The red light on a ZW or Z type transformer takes a lot of time to come on, about five seconds or better, usually something on the track will get hot if the red light comes on and stays on. You can usually tell when you have a short by the power being lost to the other outputs because as Bob N. mentioned the circuit breaker is on the U terminal side, or there is only one circuit breaker for the whole transformer.
I don’t know what the 91 circuit breakers are rated at, Greenberg’s price guide just gives the years it was made and what it could bring when sold.
Lee F.
Would it be okay to wire up a 91 to a Z transformer?? To have 2 circuit breakers protecting the wires and transformer. I know the 91 only takes an instant for it to trip and the red light come on. And as you stated the Z takes a while for the red light to come on. Thanks.
There is no harm in adding one, in series with either the common (U) or one of the other terminals. However, without knowing its current rating, there is no way to know whether it is doing you any good. Therefore, with that transformer, you should still put individual circuit breakers whose rating you know to be no more than 15 amperes in series with whichever of the A, B, C, and D terminals you’re using and wire those circuits with wire of the appropriate gauge, with 14 AWG minimum for the common.
How do you wire up the 91 with the 167?? Also, how do you wire up the 91, 167 and 66 all together?? Is there any graph or pictures or anything that show how to do this?? I have some 91’s and 167’s and one of the 66. And I would just like to know the right way to wire them up to my track and my Z transformer. Thanks.
All in series on whichever control you want this all on(A,B,C, or D).
Rob
Could you explain to me what In Series means? I am by no means an electrician and I wish I had instructions for my Number 66. I have instructions for a 167 and 91 and a Z transformer. But, They are not too clear on how to wire up everything. Thanks.
A number of 2-terminal devices are connected in series when the same current passes through all of them. If the devices are A, B, and C, and their terminals are 1 and 2, then they are in series when A-2 is connected to B-1 and B-2 connected to C-1. Then that series string can be connected into a larger circuit using terminals A-1 and C-2. Christmas-tree lights are notoriously connected in series.
You don’t think it would hurt to use some 91’s with my Z transformers?? I mean the Z does have a built in Circuit Breaker, but should it be okay to add extra protection with the use of the 91 wired to the Z and to the track? I am debating whether to get 2 more of the 91’s at my hobby shop. They are not too expensive, but is it worth it? Thanks.
You don’t NEED them.
Do you WANT them?
Will it HURT TO USE them? No.
Will it be convenient to have them? Yes.
Is there a “COOL FACTOR” using them? Maybe - it’s nice to have independent visual indication of track/train trouble from the control panel.
Will they add extra protection? Maybe. Usually with the V & Z type transformers the internal breakers open too soon when they wear out, not too late.
Is it worth it to have them? Maybe, depends on your cost analysis vs. your desire, or reluctance, as it now appears, to go ahead and use them.
Rob
Thanks for such a great answer!! I think I want them for added protection. I will head on over to my hobby shop and get some more of them. They are only like $20 each. Will look nice on the layout and control panel. Thanks again.
One more problem. My 91 has a very sensitive on/off lever. When I place the 91 on my layout, the trains running on the layout cause the on/off lever to turn off, thus turning on the red light and cutting all power to the track. Is there anyway I can make the on/off lever less sensitive? I tied opening it up and see if it can fix it, but too many moving parts inside of the 91. Should I use a little piece of tape to hold up the lever? Just enough tape to hold it up, but still when there is a derailment, it is able to set off the circuit breaker and the red light lights up. Let me know what you think. Thanks.
I have a 91 that I have, at various times, used with both my Z and ZW transformer.
It’s a magnetic type breaker, and is very, very fast-much faster than the thermal breakers in the Z and ZW.
The current rating is fairly low-in the neighborhood of 5 amps, as I recall, based on my experience.
I don’t have a fix for the loose lever, however I do recall that it required a fairly firm “shove” to get it to latch completely.
In short, I would not hesitate to use one, although it will significantly reduce the maximum current that you can draw from that particular output on the transformer.
By the way, $20 sounds really high to me. As I recall, I paid about $2 or $3 from a train show for mine. I frequently see them priced for $5 or less at shows. I’ve also paid the same for prewar rheostats.
These prewar electric accessories are quite plentiful, and the demand for them is fairly low. Shop around and you can do a lot better.