Milwaukee Deer Lodge electric switcher build

[Jim Starbuck]

440 volt seems reasonable. I read a discussion on an O scale forum where they were trying to identify the truck used for it. It’s shorter than a GP or SW truck and the best guess they came up with was some type of interurban.
I’ve never seen a photo of it with the cord attached but judging from the burn marks on the paint maybe it clamped to the lug on the side?

[sd45elect2000]

440 volt seems reasonable. I read a discussion on an O scale forum where they were trying to identify the truck used for it. It’s shorter than a GP or SW truck and the best guess they came up with was some type of interurban.
I’ve never seen a photo of it with the cord attached but judging from the burn marks on the paint maybe it clamped to the lug on the side?

It’s from a C Liner

[Jim Starbuck]

It’s from a C Liner

Cool, thanks! That make more sense than an interurban.

[sd45elect2000]

I have read, but can't swear, that this ran on 440V DC.  It certainly didn't use 3000V+ trolley voltage.

They must have used a welder then. I can’t imagine setting up an expensive transformer/rectifier just to move engines off the turntable. Maybe the welding machine was on the switcher and it plugged to,a 3 phase plug?

[nkalanaga]

Probably not a rectifier.  I'd assume they used a motor-generator set, just like the big substations, and plugged into the shop's 440 AC.  Any shop that could rebuild electric locos could easily build such a thing.

I have also read that it was built from an FM diesel truck, and that it was built from a streetcar truck, from nearby Anaconda.  Either would be possible, so I won't speculate on which it was.

[sd45elect2000]

Probably not a rectifier.  I'd assume they used a motor-generator set, just like the big substations, and plugged into the shop's 440 AC.  Any shop that could rebuild electric locos could easily build such a thing.

I have also read that it was built from an FM diesel truck, and that it was built from a streetcar truck, from nearby Anaconda.  Either would be possible, so I won't speculate on which it was.

There was a switcher prior to the one modeled that did have a trolley truck. This one though is most certainly a c liner truck. This wasn’t the first Deer Lodge switcher, there was never trolly power in the roundhouse. I think I can verify this in the Noel Holley books.

I’m also fairly certain that the turntable was three phase, most of the ones I operated were. The one exception was the air powered one. I’m guessing that a power receptacle was directly on the turntable.

I want a turntable here…

Randy

[mmagliaro]

I am suitably impressed, sir!  I never thought those pager motors would have enough torque to move ANYTHING without massive gear reduction, even with two of them, and even on a decoder.  From what I could see of the "PowerKeeper", it really doesn't look like it's anything but a big capacitor with some overload protection circuitry.  I can see it helping keep the decoder alive, but I doubt it's actually doing much for the motor.  Does your decoder have BEMF enabled on it?   I would bet THAT is the "magic" that is keeping that motor going at a reasonably steady speed.

One thing to beware of... and I really think what you did is brilliant and I am not trying to throw a wet rag on it...
Those pager motors may be able to move the engine.  But they might be quite overloaded while they are doing it.  After you run it for a few minutes, do they feel hot?  Or warm? 

[Jim Starbuck]

I am suitably impressed, sir!  I never thought those pager motors would have enough torque to move ANYTHING without massive gear reduction, even with two of them, and even on a decoder.  From what I could see of the "PowerKeeper", it really doesn't look like it's anything but a big capacitor with some overload protection circuitry.  I can see it helping keep the decoder alive, but I doubt it's actually doing much for the motor.  Does your decoder have BEMF enabled on it?   I would bet THAT is the "magic" that is keeping that motor going at a reasonably steady speed.

One thing to beware of... and I really think what you did is brilliant and I am not trying to throw a wet rag on it...
Those pager motors may be able to move the engine.  But they might be quite overloaded while they are doing it.  After you run it for a few minutes, do they feel hot?  Or warm?

Thank you Max!

There are two tantalum capacitors on the ISE board and you are correct that there’s also circuit protection on board.
With 940uF it does keep a steady albeit short supply of power to the decoder and in turn the motor control. BEMF is enabled on the decoder and ESU has built in a very wide range of adjustments that allow the motors to be controlled “just so”. It took a few hours fiddling with adjustments to get it where it is and I feel we’re on the bleeding edge between working well and not working at all.
You are also correct that I’m asking infinitely more of these tiny motors than they were ever designed for. It’s best to only run them in short intervals as things do begin to get warm. This whole project is a novelty and more of a proof of concept experiment just to see if I could actually get this little thing to run. I’m tickled that it even moves.

[Chris333]

If you could get those tiny stepper motors figured out you could power anything.

[nkalanaga]

Randy:  Thank you!  I didn't know there were two different switchers, and always wondered how an old streetcar truck could be confused for a road diesel truck.

As for the voltage, it's possible that it used AC motors, so didn't need any type of convertor.  Since it would only run at very low speeds, limited speed control wouldn't be a problem. 

[Jim Starbuck]

If you could get those tiny stepper motors figured out you could power anything.

I’m not at all familiar with stepper motors but I did a short search and OH MY!…they could open up an entire universe of animations.

[peteski]

If you could get those tiny stepper motors figured out you could power anything.

The problem with those is that they require electronic circuit which sequentially powers the coils to cause the stepping action (following the control input which determine the speed and direction).  AFAIK, the are no stepper motor controllers available miniaturized enough to use them in tiny models. Even if miniaturized, those would still likely be at least be a size of a typical DCC decoder.

Also, unlike standard DC motors, they rotate in very distinctive (jerky) steps.  How rough those are depends on the motors steps/revolution specs.  Some can also do micro-stepping to smooth out the rotation, but I'm not sure if the tiny motors are designed for micro-stepping.

Maybe some day someone will develop a DCC decoder with a stepper-motor driving section (instead of a PWM DC motor output).  This would only be viable for a control system which provided full voltage at the rails (since  steppers need full voltage powering them, even when stopped).

[Chris333]

Yes it looks like you need to know a fair bit about integrated circuits to do it, but I can deal with the noise if I can have this:

/>

/>
Nothing I could ever do, but would LOVE it.

Look at the guys other stuff on Youtube, he has many videos with tiny stepper motors... in trains.

[peteski]

Yes, the stepper noise (especially at higher speeds) is a problem. I didn't  even think about it.  But if you have the electronic and programming know-how, you can certainly build your own stepper motor controller (and shoehorn it into a small N scale loco). Maybe someday such controller will be a commercially available option (so you can buy one as easily as a DCC decoder).

Back in the '80s I troubleshoot industrial size plotters which used large steppers and yes, they used to "sing".  Or if you look on YouTube, you can see many examples of floppy disks (with their stepper-motor based head actuators) converted into musical instruments. 

[Jim Starbuck]

I got a little farther along today…railings, grabs, couplers and some details.
Details left to add are cut levers, ladders, lights, bell and whistle.
The wire details are .008” phosphor bronze wire.
The couplers are True-Scale that I cut the back of the box off and epoxied into the openings. They will never need to couple to anything so they’re just dummies. They need to be flush with the back side of the pilot because the outboard end of the worms only clear by about .020”.
I also camouflaged the riser strip on top of the truck with brake linkage made from .008” wire with pieces of .018” stainless tubing representing clevises at each end.

[ Guests cannot view attachments ]

[ Guests cannot view attachments ]

[ Guests cannot view attachments ]

[ Guests cannot view attachments ]

[ Guests cannot view attachments ]