running MTH protosound 3 locomotives together with standard DC locomotives

You have asked a lot of questions, but let me say this first. You can't run conventional DC locos on the same track at the same time as a loco operating in DCS mode. To operate DCS, you must have a constant voltage on the track, usually about 18 volts. The loco is then completely controlled through and addressed by your DCS handset or DCS Commander. You can't vary voltage levels widely and quickly as you would a conventional DC loco, as the DCS loco will indeed stop operating in DCS and revert to conventional operating. I'm not with my trains at the moment, but I think there is a polarity switch in the tender, under one of the hatches? Have you read the instructions? Always a good idea.

Dave,

I believe, although I cannot be certain, that Jean is discussing operating strictly conventionally with both a PS3 and other DC conventional engines on the same track.

If the PS3 engine was operating under DCS, there would be no problem. PS3 engines will always come up in forward under DCS on 2-rail track, since they will find and operate with the DCS signal on either rail, automatically.

I stand corrected. Barry, does that apply to 3 rail? I understood him to mean that he could control a DC conventional loco, by the transformer, but independently contol a DCS loco at the same time in DCS.

Dave,

does that apply to 3 rail?

As far as I know, it does not. However, I've never tried running my PS3s with the DCS signal on an outside rail.

JS7070,

  Jean 1st it will do no damage running a Conventional train thru the DCS, I do it all the time.  I like to run with the side receiver on the Z4K setting the track voltage at 16 and controlling the Conventional Train thru the TR key.   I also control the P2 engine on the same track using its' P2 control thru the hand held, in reality it works quite well, this in reality is a learning experience and often times

I pull the P2 controlled train into a siding and let the Conventional go past, just like the real trains operate.  This is one of the main reason why I want one step switch control added to the DCS hand held remote control, many times at this point I am using the remote switch control on my 1st level, because it is quicker switch control. 

PCRR/Dave

The Williams PRR GG1 in the 2nd picture on the 3th level is Conventional, the 2 trains on the 2nd level are P2 controlled, the MTH GG1 on the 1st level, of which you can only see the end coach cars, is P2 controlled all these trains are controlled form my DCS hand held remote at the same time.  Along with a another Conventional Weaver running around the Christmas Tree on a different track, and a large PA Silver Williams Convertional E44 pulling the big NASA train, also in the 1st picture, on a different track.   It is easier to control Conventionals and P2 trains on different tracks, however with practice they can run on the same track, controlled from the DCS hand held remote.

Note: Jean I have no P3 DC type engines at this time, I am talking about P2.

Your P3 will run like P2  also.

1) If your engine does not have a mechanical reversal switch, re-phrase the question to ask the experts here how to run PS3 engines in a multi-engine consist DC-powered conventional control.  Otherwise I see nothing stopping you from installing your own DPDT switch inside the chassis between the power-pickups and the PS3 electronics.  Make sure any answers you get are specific to PS3 (vs. PS2) since there were subtle changes in DC operation from PS2 to PS3.

2)  As you lower track voltage in DCS the engine will slow simply because there’s inadequate voltage to drive the motor.  So I believe you’re proposing operating in the small voltage zone where the engine has stopped motion but the voltage is adequate to keep the engine from shutting down (lights off, shutdown sounds play under supercap power).  As long as the lights are on, if you increase the voltage the engine should continue in the direction it was going before the motor was starved of voltage. Since the lights are on you can confirm the direction is retained by looking at the tender directional backup light if your engine has one.

Some low-cost DC power packs use unfiltered high-frequency pulses to vary the DC track voltage. These power packs work OK for driving engines that only have a DC-motor in them but check your PS3 manual as I recall there’s a discussion on recommended “pure” DC supplies or recommended power switch settings.

3) I think it is commonly referred to as jack-rabbit protection but it prevents a PS3 DC engine from taking off at 20V (forward or reverse) if 20V is applied as a step following a shutdown.  The engine must “see” a lower track voltage (it will be in the manual but I think it’s something under 10V or so) to unlock motion.  Separate from jack-rabbit protection is a startup interval where a PS3 engine charges its internal supercapacitor before it operates.  I’m not sure if you’re saying your engine’s supercap delay is 20 sec or if 20 sec is what you happened to try.  You may have found a quirk in the interaction of jack-rabbit protection and supercap charge delay in DC conventional operation but the experts here will know if the question is re-phrased accordingly.