Atlas scale electric coupler use

Joe,

  Man I can not give you an answer on this one, the guy you need to talk to on this kind of 2 rail electrical engineering stuff, is Bill Ingraham, he will probably be able to give you the correct skinny.

PCRR/Dave

"Bill Ingraham"

Who is this?

2 or 3 rail doesn't matter the O PS-3 board is the same internally.  The PS-2 and PS-3 traditional couplers are the same.  Interesting the Atlas worked, I upgraded one and they did not work.  So I guess it depends on the ohms of the coil.  The PS-2/3 are low ohm coils with a quick pulse of current.  G

MTH PS2/3 couplers are about 2.4 ohms, the PS/1 or any TMCC/Legacy couplers are around 7 ohms.  The two aren't compatible.

 So I must have got lucky with the Atlas?

I'll put my meter to the coil. It might then work with the PS3.

The Atlas scale couplers I have are about 7.2 ohms and take around 11 VAC minimum to trigger.  They don't fire when I connect them to a PS/2 board.

I'll be back with a video then.

http://youtu.be/3PMZeqGgRyY

hooking up to a KD equipped car. It's been so long I was out of practice. You have to back up a train to release the pressure for the coupler to un-hook.

Joe how about a close up of the coupler and what is the ohm reading?  G

Sure G! I grabbed an extra and it read 6.5 ohms. click on picture:

hi joe thats me. i just finished a ps3 install in an atlas gp35 (2 rail)fixed scale coupler in the front and a spare premier 3 rail remote coupler in the rear. i now can command all functions including the remote coupler with my dcs remote.it is my favorite yard switcher and still 2 rail.

Sorry Willygee!

and I'm a fan of yours! I didn't recognize your real name.

  tis ok...i just added another mth remote coupler to a tail end (5 engine MU)unpowered gp38 2 rail by extending the harness to the powered unit in front of it. works great in separating the consist and i dont have to leave my couch.

You can send directional lights over too.  A double pole switch and you can control them similar to the aux tender.

Joe,  Your lucky on the couplers.  Those Atlas must release easy.  I have not had the same luck with the 4 Atlas conversions I did.  2 had unique couplers so they had to stay.  G

Since the PS/2 board applies PV (more than 11V) to the MTH couplers with 3x or so lower resistance, it seems the necessary power is available.  I'm imagining you building a pulse extender circuit to lengthen the time the PS2 board drives the Atlas coil. 

Joe, The PS2 One-Gauge couplers are 4 - 5 ohms so if you're reading 6 or so with the Atlas style and they work I wouldn't worry about it 

Well, The other unknown factor is the soundfile.  Since 1 and O are the same PS-2/3 board, the soundfile could be adjusted to handle a coupler design that required a higher internal resistance.  I wonder why the designer even went with a change from PS-1 coupler.  G

I'm also curious why they felt the need to change the coupler to a different design for PS/2.

Well, The other unknown factor is the soundfile.  Since 1 and O are the same PS-2/3 board, the soundfile could be adjusted to handle a coupler design that required a higher internal resistance.

I've been doing PS2 conversions in large scale locomotives since 2006 and have used many different O Gauge soundfiles, none of which failed to fire open a one-gauge protocoupler.

 This engine has been running this way for years. I don't worry about it. I was just shocked when others that I listen to, said it won't work. I believe them when they say it didn't work for them. I just know ....... better????

 Maybe there were different runs of the coupler that had different triggering voltages?

All the ones I've tried have worked with all the different sound files so far. (all diesel!)

 Hmmm, all have been diesel and all have been modern GE sound files?

Get to thinking about it the soundfiles really don't matter either as the couplers are all fed 5V via the purple wire. 

Actually they are FED about 24V via the purple if track voltage is 20VAC.  But the current doesn't flow unless the FET fires and the time of duration is controlled by the sound file. So it does matter.  A program tweak and the fet stays on longer and more effective voltage or current passes.  G

However, there is no way for the user to do that tweak.  Does MTH have different durations for couplers in different sound files?

I know that John.  Just explaining.  Maybe they do for 1 gauge or scale couplers.  They do it all the time to make corrections for smoke FET and Motor curves.  It is all built into the Flash file.  Apparently they are revising the PS-3 flash files almost constantly for issues, especially European mods.  G

Well if it helps, I'm running with the L 180w PH bricks, so 18 volts??

Regular O gauge GE soundfile. Started with the AC6000 but it was too loud. I'm pretty sure it was a AC4400 file?? I really should keep records of these things.