Double proto coupler firing.

It's very likely that you'll kill the coupler FET with a double load, I'd find another way.

@gunrunnerjohn posted:

It's very likely that you'll kill the coupler FET with a double load, I'd find another way.

Thanks John.

You could add a relay and use that to provide power to the second coupler.

@gunrunnerjohn posted:

You could add a relay and use that to provide power to the second coupler.

Dallas the PHD electronic genius here John ...............do you have a visual diagram ?

@gunrunnerjohn posted:

You could add a relay and use that to provide power to the second coupler.

@Dallas Joseph posted:

Dallas the PHD electronic genius here John ...............do you have a visual diagram ?

Edit- a major note here is the second coupler- ideally should be a LIONEL or MTH PS1 style coupler- rated for FULL track voltage!!!

A PS2/3 style electrocoupler is wound with a coil meant for LESS than track voltage and might fail or overheat if supplied FULL track voltage.

Actually, being honest and reviewing this more, I'm not sure if the parallel load of both a factory PS3 coupler, and a relay coil in parallel is safe either. It just brings up a lot of limitations of the output of the PS3 board and the tiny SMD FET used. In other words, I'm sure the FET could fire a relay, maybe both couplers off the same relay output so that the board only sees the coil of the relay.

Going further, if you wanted to stick with original PS2/3 style couplers, then we also need that voltage source and ground- so more wires potentially in the tether system. I know PS3 diagrams could show us the connections to PV (positive voltage from the board) and pcb ground.

I'm just saying, sure, I tried to help out and draw a diagram of what was being discussed. I'm not sure I can endorse this as being the best solution and the added inductive load and kickback of a relay coil in parallel to an existing coupler could push the limit and be as bad as 2 couplers.

Again, sorry, was trying to help, but the more I look, the more unsure I am of the best solution, and what I'm thinking- depending on requirements for using either PS2/3 style couplers, VS older MTH PS1 or Lionel couplers meant to fire at higher voltages safely, kinda changes how and what happens here.

I don't want to give advice that then results in a board failure or other major malfunction.

@Vernon Barry posted:

Actually, being honest and reviewing this more, I'm not sure if the parallel load of both a factory PS3 coupler, and a relay coil in parallel is safe either. It just brings up a lot of limitations of the output of the PS3 board and the tiny SMD FET used. In other words, I'm sure the FET could fire a relay, maybe both couplers off the same relay output so that the board only sees the coil of the relay.

Let's not get carried away.   I think the addition of a relay that draws maybe 40-50 milliamps isn't going to damage the FET that is able to deliver a couple of amps to fire the DCS coupler!

The point about changing the coupler or providing a suitable power source for the PS2/3 coupler is well taken.

So the idea of adding inline resistors before the original coupler and before the auxiliary coupler  would be of little value !? 

@Dallas Joseph posted:

So the idea of adding inline resistors before the original coupler and before the auxiliary coupler  would be of little value !? 

The resistor would preclude the coupler firing at all.  The coupler internal resistance is only around 3 ohms, if you added a resistor that cuts down the current to any significant amount, it would simply not open the coupler.

@gunrunnerjohn posted:

The resistor would preclude the coupler firing at all.  The coupler internal resistance is only around 3 ohms, if you added a resistor that cuts down the current to any significant amount, it would simply not open the coupler.

Thanks again John.          It's bebginning to look like I'll have to attach a freight car  coupler from my inventory bin and operate the calf coupler by hand..........only other option would be to run wires to a calf rear  proto coupler from the switcher front coupler wiring .....hmm.

That would be the most expedient solution the front coupler control.

@gunrunnerjohn posted:

That would be the most expedient solution the front coupler control.

Seems like it would be a contradiction to switcher operation but I think you are right John.👍

I just received a ps3 Pennsy Premier  B  unit  for the A unit I have .........shouldn't be any big decision using a smaller dummy coupler for the front of the A unit and to wire to the rear of the B unit with a short proto coupler from the wiring from the front A unit.

Thanks for your advice John.