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I have an old Lionel GP9 2380 with an LCRU2 TMCC control and RailSound 2.5 broads in it. I am hoping I can pull them from the GP9 and put them in a Williams E7 which I believe have two DC motors in it. My plan is too use a bridge to convert the AC output to DC and connect the RailSound wires that go to the mechanical switch on the GP9 trucks to the DC motor on the E7.

Can anyone tell me if this will work or am I forgetting something?

Thanks for any help.
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THe problem is that the rectifier on the AC output will always have + DC on the rectifier + lead and vice versa for the negative lead. So no direction control. The rectifier needs to be infront of the TRIACS. Early DC Motor Controllers used the same TRIACs on the LCRU2, but the rectifier was on the board as and input to the Triac H bridge. G
Carl,

So if I understand halfwave DC there should be no problem hooking the Railsound 2.5 broad to the DC motor instead of using the mechanical switch correct?

Also on the Tuveson website it is mentioned that halfwave boards have a problem with DC voltage offset and legacy sound boards cannot be use on the same track. Is that the case with the way suggested?

I don’s half any legacy engines now so it’s not a problem just want to know if it will be a problem down the road.

Again, Thanks for all your help.
Carl, Your words don't match your picture. Yellow and Blue are normally to the armature brushes. Green to the field.

Your diagram replace the AC motor with a diode, and use the field to the DC motor going to ground.

I still think putting a full rectifier infront of the triacs is best, but that requires board modification. G
Yes the diode goes where the the brushes would go. Ooops.

The Triacs reverse the polarity of the diode which is in series with the can motor through the board wiring.

It has been a long time since I did this drawing and I was going from memory.
It is so simple to do why mess with the board? It did the job for my needs.

This was done along time ago before any driverboards were available like there are now.

The choke was for two rail operation to improve the Signal strengh but would not be needed on a 3 rail layout.

Carl
Carl, This does work I agree. The triacs reverse the current flow through the armature brush leads, while maintaining current flow in the same direction through the field windings (green lead).

Performance and safety are the only issues. Half wave drive for the motor vice full DC. Also an undetected short on the diode would revert to pure AC to the DC motor possibly damaging it if undetected. The full wave rectification before the Triacs would be safer then a single diode, but would require board modification to make it work. G
Carl,

I final found the time to try this out. But I seem to have a problem, I hooked up the wires per the diagram with the exception of hooking them up to the DC motors. When I put a meter on the black and green wires, I am getting full 18V AC little or no DC. The Railsounds, directional lighting works fine so I know the signal is getting to the board. Any ideas of what could be wrong or things I could check out? I did try 2 different diodes which I just brought new.

Thanks for any help.

Phil
Phil, a meter doesn't provide any significant load on a circuit it is used to measure. I think Carl's site has a better diagram of the H bridge arrangment of the TRIACs, but current flow is need throught them to operate the way they are connected.

To test your unit as an AC LCRU, you need two loads. Once to represent the motor and one to represent the field. Light bulbs work. G
I've been using Carl's wiring to run DC motors with a LCRU for close to 10 years now.
Suddenly i've run into a problem: i've added an ERR Sound Commander to the circuit in two identical locos (GG1's) and have developed a problem in only ONE of them. In one installation everything works (start-up sounds, horn, bell; directional lighting; and engine runs perfectly). However in the second installation with the Sound Commander connected i get ONLY start-up sounds (NO horn or bell) and the engine will NOT move NOR change directional lighting -- disconnect the Sound Commander and the engine runs as it should.
Any ideas before i call ERR tomorrow??
jack
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