MTH & Lionel power question

I am surprised there haven't been a lot of responses, maybe Friday the 13th has something to do with it?

The big issue is the MTH bricks have a very good circuit breaker and old transformers do not. You would need to add something similar without knowing the specs on what you are trying to mimic or protect in the z controller.  There are a bunch of threads on breaker choices and airpax was one many liked.

@SteveH who has done research on these options

Using another transformer with the Z controller could be done if a few considerations are understood and implemented.  Before getting into those, please help me understand what benefits are expected by using a Z Controller with an already variable output transformer?

@SteveH posted:

Using another transformer with the Z controller could be done if a few considerations are understood and implemented.  Before getting into those, please help me understand what benefits are expected by using a Z Controller with an already variable output transformer?

Some of the older Lionel, vary the output voltage....only. Which requires a lowering of the voltage to change direction in "standard" operation no reverse button on the transformer. They also have, continuously "on" taps that supply 15 v. Inserting any controller into the variable output allows directional stop/change for the train, and turns the continuous output into a variable, with the rev button advantage. (and a horn button thinking about it now.)

I do not intend to do either of the above, but looking at a spare Z yesterday, prompted the question, in the event that someone wanted to use the Z for either purpose. I can see someone running a train with the variable, and using the Z to vary the voltage on the accessory tap of the transformer....or vise vesa if they wanted the advantage of the reverse and the horn button on that channel/output.  More of a question for information, born from curiosity.

EDITED: I just read on another thread, it was posted that there is a"Z controller for the 750 brick which lowers output from 21v to 18v," and I am guessing,  a Z controller for the 100 brick, which I assume does NOT lower the 18v output of it!! From Vernon.

Thanks, Greg

@cngw posted:

Some of the older Lionel, vary the output voltage....only. Which requires a lowering of the voltage to change direction in "standard" operation no reverse button on the transformer. They also have, continuously "on" taps that supply 15 v. Inserting any controller into the variable output allows directional stop/change for the train, and turns the continuous output into a variable, with the rev button advantage. (and a horn button thinking about it now.)

I do not intend to do either of the above, but looking at a spare Z yesterday, prompted the question, in the event that someone wanted to use the Z for either purpose. I can see someone running a train with the variable, and using the Z to vary the voltage on the accessory tap of the transformer....or vise vesa if they wanted the advantage of the reverse and the horn button on that channel/output.  More of a question for information, born from curiosity.

EDITED: I just read on another thread, it was posted that there is a"Z controller for the 750 brick which lowers output from 21v to 18v," and I am guessing,  a Z controller for the 100 brick, which I assume does NOT lower the 18v output of it!! From Vernon.

Thanks, Greg

Thank you for outlining your expectations.  @Vernon Barry 's explanations in the other thread: Z750 CONTROLLER - Help needed again please are helpful in discussing some of the considerations of using the Z-Controller with an alternative to the MTH power bricks.  Summary: all Z-Controllers are not the same and some reduce the input voltage by a fixed amount even at full throttle.

To be clear the Z-Controller will only output a lower voltage than what's on its input.  Also it does' not use a rheostat to reduce the output voltage.  Instead, it uses semiconductors to very rapidly switch on and off the power.  50 or 60 Hz sine wave input, higher frequency chopped sine wave output.  There's lots of info here on the forum about the pros and cons of chopped sine-wave output, beyond the scope of this reply.

The other consideration as mentioned by @hokie71 is that over-current protection (breaker or fuse) is recommended, especially if the substitute transformer is capable of delivering more power than the Z-controller is designed to handle.  MTH Z-750 and Z-1000 bricks both use Thermal Breakers, rated for 4 and 6 Amps respectively.  I suggest matching one of these breaker values to the corresponding Z-controller if using with an alternate transformer.

So to answer your original question:

"Can the Z controller safely be used with older Lionel transformers: along the line of the 75 watt Trainmaster that they sold? Or other older transformers?"

Yes, as long as you account for and implement the preceding.