Stainz Double Heart Bypass

Some may remember that a while back I created a back to back "double stainz" which has common pick up and motor wiring, making it effectively a single 4 axle locomotive with twin motors ....



This has proved one of my most popular loco's with pulling power second only to the"Mallet".
However as the only wiring I did was to permanently couple (with correct polarity) the sockets on the rear cab of each loco, it doesn't have a DCC chip and it runs as analogue.

So I've decided to upgrade it to digital, and hopefully a new Massoth XL 3amp decoder is already winging it's way towards me from Germany.

This is likely to be my most challenging "chipping" yet, even more complex than the Mallet, as various umbilical wires will have to be run between the two loco's and both sets of motor block wiring modified. So in the interests of amusing others on this forum I will post a picture diary of progress!

I also recall that Paul (Stainz) Holt did something similar, so if you have any tips for me Paul they'd be much appreciated.

Very interesting but one wonders....Why? (edit) perhaps i should explain that question: why is it connected like that and not as a normal double header?

mikey

mikeyh wrote:

Very interesting but one wonders....Why? (edit) perhaps i should explain that question: why is it connected like that and not as a normal double header?

mikey

Quite simply because I like it that way! And as you know Mike, there is no need for prototypical precedent on my toy railway!

Another reason is that it is much simpler to wire and hide the wires back to back!

You can't see in the pic but the driver in the second cab is facing backwards (forwards) if you see what I mean?

It has also caused much amusement amongst visitors.

I was going to suggest boiler to boiler, but resisted (until now) then it would be running backwards each way, like a cab forwards BIG BOY, I joke.
Either way I can see the advantage of running 2 Stainz together.

There's a prototype for everything. Just superglue the cabs together.

Carl Hibbs wrote:

There's a prototype for everything. Just superglue the cabs together.

Ah but then it wouldn't go round R1 curves

GWhizz wrote:

Carl Hibbs wrote:

There's a prototype for everything. Just superglue the cabs together.

Ah but then it wouldn't go round R1 curves

Just what I was thinking

The other advantage is to have two motors, heavy power and 12 electrical pick ups. While technically LGB says not to route train power via the plugs, on the early round type connectors, I do not see it as a probem, how they do the 2015/7 tender locos.

Carl Hibbs wrote:

There's a prototype for everything. Just superglue the cabs together.

One of the custom modifiers of LGB back in the 1970s/80s in Germany made some of these out of two Stainz locos. A friend who is an avid LGB item collector and historian has one in his collection, painted in a military grey color.

Hey, I like this Smiley!

Spule 4 wrote:

The other advantage is to have two motors, heavy power and 12 electrical pick ups. While technically LGB says not to route train power via the plugs, on the early round type connectors, I do not see it as a probem, how they do the 2015/7 tender locos.

I had actually upgraded the wiring to the plugs in any case, but all that will have to be reviewed as I think I'm going to need a 6 wire umbilical between the two units.

I'd better draw myself a circuit diagram.

Just for Brian........

Brilliant - thanks Carl

Here's the wiring diagram ...

Hi Brian

I have teamed up 3 pairs of Stainz, but in every case each loco had its own decoder. All I did was make sure each loco of the pair had the same address and that each decoder's CV s were all identical. It also helps that both motors run at virtually identical speed.
This is easily tested by running both locos simultaneously at the same speed step - if they remain the same distance apart, you have a match.
(The back emf will take care of minor duifferences in motor speed).

Also, to ensure electrical continuity, I connected the track pick up wires from each loco together via a small plug, so the locos can be disconnected and run on their own if I want them to.

You can just see the wires and plug in this pic......

paul stainz holt wrote:

in every case each loco had its own decoder. All I did was make sure each loco of the pair had the same address and that each decoder's CV s were all identical.

I knew you'd done something like that Paul.

Being a cheapskate, I'm going for the one decoder solution and permanently coupled Stainz's.

Fingers crossed!

Ah, missed the DCC bit, that would make things a bit more involved, but good show regardless!

Not a criticism, just something i want to know! I have five stainz and each motor draws a slightly different amount of electric power. One of them is much faster than the others. Noting what Paul has said, if the stainz' do not match Exactly is there not a risk of motor burnout? Does using digital adjust the powerdraw automatically?

mikey

mikeyh wrote:

Not a criticism, just something i want to know! I have five stainz and each motor draws a slightly different amount of electric power. One of them is much faster than the others. Noting what Paul has said, if the stainz' do not match Exactly is there not a risk of motor burnout? Does using digital adjust the powerdraw automatically?

mikey

That's a very, very interesting question Mike!

As you know, I run DCC on my track so every analogue motor even when "stationary", is subject to 18v AC going through the motor which creates a humming noise.

The DCC system progressively (goodness knows how this works) interrupts or presumably enhances one of the polarities of the AC when you control an Analogue loco and allows it to move. You can only operate one analogue loco at a time on a dcc system, although you can concurrently run hundreds of chipped loco's at the same time. LGB loco's are all warranted, even the early ones to withstand this AC abuse and this testifies to the robustness of LGB.

Running Loco's from other manufacturers particularly PIKO are known to burn out when subject to this abuse, one reason why I would never ran Phil's, now Van's analogue Piko Railbus on my DCC system.

I also recently repaired a "Lil Critter" for Van and I was amazed to see the motor rated at 12volt although they sell it as an 18V motor.

I've probably drifted off point here, but my conclusion is that LGB motor blocks are built like "Brick S**t Houses" and can withstand any amount of abuse!

The minor speed/current draws you allude too would probably be taken up by slippage on track by one of the loco's in a coupled situation.

Us DCC bods also run One, double, triple or even greater headers on one train ( I think 5 or more is possible). Even though we programme the speed curves of each loco to match, the individual loco's may well run at slightly different speeds( as evidenced when you run them uncoupled on the same track), but it is not a problem.

Back to my Double Stainz, I plan to wire both motors to the single output of the XL chip, this is rated at 4 amp nominal and 5 amp max so shouldn't have any problems coping with disparate requirements of the two motors.

I'm working on the fact that I haven't (YET) burnt out the motors despite the high abuse of DCC.

Of course, if events don't work out, and I end up with two melted Stainz, I'll wish I never started this thread

Thanks Brian thats a terrific answer (even I understood it!!)

mike

I didn't realize DCC ran on AC. I guess it would have to or you'd have to worry about isolation on reversing loops.

Mikey- double heading works well with analog as well; the two motors sort of equalize as long as they are anywhere close in speed. Track slippage (mostly imperceptible) takes up some slack as well.

KleineDicke wrote:

I didn't realize DCC ran on AC. I guess it would have to or you'd have to worry about isolation on reversing loops.

Mikey- double heading works well with analog as well; the two motors sort of equalize as long as they are anywhere close in speed. Track slippage (mostly imperceptible) takes up some slack as well.

Also taken up by the back EMF programmed into each chip. (Back EMF ensures that a chipped loco runs at the same speed, whether its climbing, descending or running on the flat or going round a tight bend).
I had an analogue loop wired up just before the top line was connected to the main layout - it was noticable that the DCC line locos ran at constant speed where as the analogue line's loco would change speed depending on gradient.

KleineDicke wrote:

I didn't realize DCC ran on AC. I guess it would have to or you'd have to worry about isolation on reversing loops.

Mikey- double heading works well with analog as well; the two motors sort of equalize as long as they are anywhere close in speed. Track slippage (mostly imperceptible) takes up some slack as well.

You actually still have to isolate reversing loops, otherwise the polarity would short out and the end of the loop as one end of the track would be positive and directly connected to a negative track in the same instant, as part of the AC cycle, if you see what I mean?

DCC gets round this by employing a clever gizmo ( don't ask me how it works ) which detects a train entering the isolated loop and automatically switching the loops polarity to that of the entry track. Whilst the train is in the loop the train continues on that polarity until it leaves and the same gizmo switches back again so it can exit the loop the wrong way round so to speak!

You can only run one DCC train at a time into a DCC reverse loop and you can't run an analogue loco into a reverse loop on a DCC track at all! It goes mental because as the polarity changes it immediately want's to go into reverse and straight back out again! The chipped loco's have clever electronics that keep em going forward whatever polarity you put them on !

paul stainz holt wrote:

KleineDicke wrote:

I didn't realize DCC ran on AC. I guess it would have to or you'd have to worry about isolation on reversing loops.

Mikey- double heading works well with analog as well; the two motors sort of equalize as long as they are anywhere close in speed. Track slippage (mostly imperceptible) takes up some slack as well.

Also taken up by the back EMF programmed into each chip. (Back EMF ensures that a chipped loco runs at the same speed, whether its climbing, descending or running on the flat or going round a tight bend).
I had an analogue loop wired up just before the top line was connected to the main layout - it was noticable that the DCC line locos ran at constant speed where as the analogue line's loco would change speed depending on gradient.

As you can tell Paul, I'm no electronics expert, but how is back EMF compensated when wiring two motor blocks into a single chip? As per my Mallet, proposed double stainz and any of the new LGB twin moter DCC locos like the Saxon?

GWhizz wrote:

As you can tell Paul, I'm no electronics expert, but how is back EMF compensated when wiring two motor blocks into a single chip? As per my Mallet, proposed double stainz and any of the new LGB twin moter DCC locos like the Saxon?

I don't think it is Brian, you're relying on matched motors, which they generally are when both are brand new (Buhler in the case of LGB).

In the case of connecting two locos together of different ages and possibly different wear rates on each motor, its wise to do the rule of thumb test where you set both locos off simultaneously (on analogue) with a measured gap between them, if the motors are compatible, the gap won't change.

paul stainz holt wrote:

In the case of connecting two locos together of different ages and possibly different wear rates on each motor, its wise to do the rule of thumb test where you set both locos off simultaneously (on analogue) with a measured gap between them, if the motors are compatible, the gap won't change.

That's good advice Paul and actually reflects Mikey's original concern over motors drawing different currents.

Whereas the disparity in motors running under analogue would be dissapated by track slippage, could the disparity in some way feedback into the chip and damage it?

GWhizz wrote:

paul stainz holt wrote:

In the case of connecting two locos together of different ages and possibly different wear rates on each motor, its wise to do the rule of thumb test where you set both locos off simultaneously (on analogue) with a measured gap between them, if the motors are compatible, the gap won't change.

That's good advice Paul and actually reflects Mikey's original concern over motors drawing different currents.

Whereas the disparity in motors running under analogue would be dissapated by track slippage, could the disparity in some way feedback into the chip and damage it?

Its the gearbox and motor which suffers if there is disparity in the two motor speeds, not tried it though ! As far as I know the chip is unaffected.