Voltage Speed Control - Double Main Fed From KW (Conventional Engines)

A second TPC or PowerMaster? Or use one of the variable KW outputs directly?

@bmoran4 posted:

A second TPC or PowerMaster? Or use one of the variable KW outputs directly?

Since all the wiring has been done for some time now, and a pain to access. I rather use a device to insert into track supply to each main rather than separating into 2 circuits. Both tracks are shared with the same power wires from the TPC400.

What you are looking for is rheostats like these Lionel types... which are current-limiting(not voltage limiting). The operation of the trains becomes unpredictable though because the voltage drop varies with the load. Any whistle / horn / bell / direction activation to the TPC w/ the CAB-1 still operates both tracks.

And with just two rheostats, the TPC, Command Base, and CAB-1 would be unnecessary... leading to the use of just the KW A & B throttles is all that you would need.

The MUCH simpler option is to run ONE more wire, and use another TPC, or scrap the TPC & Command Base, for two PM-1 Powermasters.

@ADCX Rob,  the rheostats will not be independent if wired to per @R Whitley's diagram as Track 1 will influence Track 2. Modifications would be required, and since we are modifying, the aforementioned options seem much more capable.

Additionally, there is no need to eliminate the TPC or Base to use one or more PM-1 PowerMasters.

@bmoran4 posted:

there is no need to eliminate the TPC or Base to use one or more PM-1 PowerMasters.

There is no need for the Command Base with the use of two PM-1 Powermasters.

@ADCX Rob posted:

use another TPC, OR scrap the TPC & Command Base, for two PM-1 Powermasters.

@bmoran4 posted:

the rheostats will not be independent ...

Sure they would, here is his diagram... one wire moved.

@ADCX Rob posted:

There is no need for the Command Base with the use of two PM-1 Powermasters.

But why remove the base? Sure, it isn't needed for a two PM-1 PowerMaster setup for conventional operation, but since it already is in the inventory, why not use it for any potential TMCC use?

@ADCX Rob posted:

Sure they would, here is his diagram... one wire moved.

I stated the diagram would not work as is - you followed up by modifying the diagram due to the need to splitting the tracks in to two distinct circuits. If split in to two circuits, any of the other suggestions are worlds ahead of the ancient rheostats.

I forgot to mention that I will be running some TMCC engines in command mode.

@R Whitley posted:

I forgot to mention that I will be running some TMCC engines in command mode.

That's a pretty important feature to retain.

@bmoran4 posted:

I stated the diagram would not work as is - you followed up by modifying the diagram due to the need to splitting the tracks in to two distinct circuits. If split in to two circuits, any of the other suggestions are worlds ahead of the ancient rheostats.

Except that he has forced the restriction that the wiring is already in place. Something has to give or it's an impossible task.

"Since all the wiring has been done for some time now, and a pain to access"

@R Whitley posted:

I need you guys input on how to control engine speed on 2 mains with a KW supplying power.

Will this suit your needs?