large transformers

[Anonymous]

There were many mentions of adding fast acting circuit breakers. What size / type / brand should I look for if I wanted to use an older transformer?

[Anonymous]

There were many mentions of adding fast acting circuit breakers. What size / type / brand should I look for if I wanted to use an older transformer?

[lionelsoni]

I like to use self-resetting automotive circuit breakers, which are small, inexpensive, and available in various current ratings at any parts store.

[lionelsoni]

I like to use self-resetting automotive circuit breakers, which are small, inexpensive, and available in various current ratings at any parts store.

[SPFan]

Bob, Are the automotive breakers you are using a "fast acting" type or thermal? Its my understanding most inexpensive breakers are thermal types. A lot of these require at least a 135% over current to trip immediately. Probably OK for conventional engines but maybe too slow for electronic types? If they do act immediately is there a specific brand or application to look for?
Pete

[SPFan]

Bob, Are the automotive breakers you are using a "fast acting" type or thermal? Its my understanding most inexpensive breakers are thermal types. A lot of these require at least a 135% over current to trip immediately. Probably OK for conventional engines but maybe too slow for electronic types? If they do act immediately is there a specific brand or application to look for?
Pete

[lionelsoni]

I think you're right that they're thermal. However, I have my doubts that any locomotive, modern or ancient, benefits from faster circuit opening, since the overcurrents are almost always due to short circuits between the transformer and the locomotive, usually derailment, and so pose no danger to the locomotive, which sees only reduced or no voltage. The only situation I can think of in which the circuit breaker would protect the locomotive is when it is overloaded, in which case the overheating that would cause the damage comes on gradually, so that the speed of the breaker is unimportant. Even then, one would have to be very lucky to have a breaker whose characteristics so exquisitely matched the locomotive's as to trip at the right time, neither too early nor too late.

[lionelsoni]

I think you're right that they're thermal. However, I have my doubts that any locomotive, modern or ancient, benefits from faster circuit opening, since the overcurrents are almost always due to short circuits between the transformer and the locomotive, usually derailment, and so pose no danger to the locomotive, which sees only reduced or no voltage. The only situation I can think of in which the circuit breaker would protect the locomotive is when it is overloaded, in which case the overheating that would cause the damage comes on gradually, so that the speed of the breaker is unimportant. Even then, one would have to be very lucky to have a breaker whose characteristics so exquisitely matched the locomotive's as to trip at the right time, neither too early nor too late.

[pennsy_fan]

Hi guys, Im in a bit of a quandry, here
I have two KW's powering my layout. (one for trains, one for accesories)
The whistle/horn rectifier went out again, (second time). & I had the idea of just going ahead & buying a command set & a tpc400. It solved the whistle rectifier problem & everything is just peachy now :-).Now I mostly run conventional engines.(Have 1 command geep),Now, Ive read that the newer power sources are best for train operation & postwar xfrmrs are best relegated to acc. control. Im wondering if its best to get a powerhouse (180 watt) to operate my 12 x 9 ft. layout. relegating my kws to acc. power only. Any thoughts?

[pennsy_fan]

Hi guys, Im in a bit of a quandry, here
I have two KW's powering my layout. (one for trains, one for accesories)
The whistle/horn rectifier went out again, (second time). & I had the idea of just going ahead & buying a command set & a tpc400. It solved the whistle rectifier problem & everything is just peachy now :-).Now I mostly run conventional engines.(Have 1 command geep),Now, Ive read that the newer power sources are best for train operation & postwar xfrmrs are best relegated to acc. control. Im wondering if its best to get a powerhouse (180 watt) to operate my 12 x 9 ft. layout. relegating my kws to acc. power only. Any thoughts?