Re-Motoring Walthers Heritage 2-8-8-2

[Chinapig]

Hi
The motor went on my loco recently and I re-motored it with a Tenshodo LH17 open frame motor measuring 17 x 13 x9.5mm as in the link here.

http://www.roxeymouldings.co.uk/product/327/tenshodo-lh17/

The motor that came out was a flat can measuring 19 x 15 x10mm.
The new motor performs smoothly once the loco has got started but when starting it's a bit hit and miss as to what voltage will get it moving and slow running is out of the question.
Has anyone successfully replaced this motor?  Any advice appreciated.

Cheers, Ted

[peteski]

I haven't replaced motor in this loco but I'm curious as to what happened with the original one.  It was non-repairable?  Motors are usually pretty robust.  It is not easy to let's say burn up a winding on the armature and brushes are also usually replaceable.

You might want to contact Walthers service dept. They might be able to find a replacement motor for you.  While they don't sell parts per se, they are quite accommodating if you need a part.

[mmagliaro]

That Tenshodo motor looks very similar to motors I see in a lot of older N Scale brass.  It looks a lot like
the Mashima M16K.  It is powerful, but my experience with it is that it isn't particularly good at low speeds.  If it is geared down enough, it performs great.  In fact, I've repaired a fair number of brass engines with that motor where I decided to leave the motor as-is because it ran so well.

But...

I suspect that it is just too fast for the 2-8-8-2 to give you the low-end predictable start-up you are looking for in that engine.   The straight-wound armature is going to hurt your low-speed start-up.   Since the original was 19 x 15 x 10, I would be inclined to try a Mashima 10 x 20.  which is 10x12 x 20 long and
should fit, maybe with a tiny bit of frame reaming on the length.  Mashima can motors are generally very very
powerful for their size, with excellent low-speed performance characteristics.

http://www.hollywoodfoundry.com/MHK1020.htm

[CodyO]

My dad and I also had to replace ours. It took awhile to find a good motor what enough RPMs to work. Ended up using an out of production NWSL motor found at a train show. Sorry don't have the model number. Walthers had none when I asked 2/3 years back. But maybe they will now so worth a shot.

[Chinapig]

Thanks for your comments, guys.

peteski, the first motor ran, as does the second one, but not with enough control of the low end speed.  It also lurched when at higher speeds.  I tested the loco with the motor removed and there didn't seem to be any binding so I put the fault down to the motor.  As you say, the things are pretty robust - I was amazed that it still worked after holding it under a gas flame to get the flywheels off    The second motor is better but not as good as I would like it.  Yeah, I contacted Walthers who said they had none in stock.

mmagiliaro, I may very well give the Mashima 1020 a try.  I was considering it initially and wish I had gone for it now.

Cheers, Ted

[peteski]

Thanks for the clarification Ted.  I run mine on DCC (with the factory-installed QSI decoder). Mine has pretty decent slow speed. Good decoder with good BEMF functionality can pretty well mask the slow speed deficiencies of the motor.

[Chinapig]

Mine's running on DCC also, with the factory installed decoder.  The decoder is the Q1a Sound according to the manual that came with the model.  The on-line manual says on page 12 in a big yellow block that BEMF and Calibrated Speed Control are not included in the Q1a due to threats of litigation etc etc.  Because of this I've never bothered to try to adjust the settings.

I'm going to give it a try to see if it makes any difference.

Just tried and my loco won't accept any changes to the BEMF settings.  I'm usin JMRI, by the way.

Just been mucking around a bit more and, following the instructions on page 105 of the on-line manual, I changed the throttle mode from Standard to Regulated and it's done it.  I can get it so that one revolution takes thirty seconds.  Okay, that's on a rolling road but I have great hopes for this.  Hmm, perhaps the old motor was all right after all - I don't think I want to go there

I'm really pleased with this so thanks to all who have contributed 

Cheers, Ted

[peteski]

That's great Ted!
I'm also glad that I brought up DCC.  I remember futzing around with the CV settings, but that was many years ago when I first bought this loco. I love QSI decoders but they do have a phone-book size manual with hundreds of CVs to play with.  Now that you've mentioned the adjustment which worked that does ring a bell. 

[central.vermont]

Just wondering if this motor is the same or close to what the Atlas 2-8-8-2 has?
There are a couple of them on Flee Bay right now.

http://stores.ebay.com/That-Train-Place/N-Motors-/_i.html?_fsub=3423066017&_sid=353828397&_trksid=p4634.c0.m322


Jon

[mmagliaro]

Just wondering if this motor is the same or close to what the Atlas 2-8-8-2 has?
There are a couple of them on Flee Bay right now.

http://stores.ebay.com/That-Train-Place/N-Motors-/_i.html?_fsub=3423066017&_sid=353828397&_trksid=p4634.c0.m322


Jon

No. The LL 2-8-8-2 motor is nothing like the motor used in that old Atlas/Samhongsa 2-8-8-2, and the old
Atlas motor was not all that great anyway.  I fixed one of those up once, with a burned out motor, and put a Mashima
in as the replacement (and it ran better).

[Chinapig]

Hi
Just want to clarify on a misleading point I made earlier.  I was mislead into thinking that the decoder didn't have BEMF as the manual said "BEMF Speed Control and Calibrated Speed Control are not included in the Q1a due to threats of litigation etc etc".  BEMF is there but there is also a list of four different types of speed control to choose from, two of which (BEMF and Calibrated) are not supported.  BEMF can be adjusted and the loco responds to the adjustments.
I spent a long time playing about with the BEMF CVs and have got the loco running very well now.  I must say that the manual is very over technical to a level that I just didn't understand and I just had to play around with the fifteen different CVs until I was happy with the result.
Lovely running loco now though 
Ted

[central.vermont]

Good news to hear Ted!!
Just one question though, did you end up putting the old motor back in?
Sounds like the old motor may be just fine.

Jon

[mmagliaro]

Since this is yet another example where decoder behavior conflates the diagnosis of an engine, even to the point
of possibly spurring an unnecessary motor swap, I feel I must bring something up that I have mentioned before.

When an engine isn't running right, the very first thing you should do (other than maybe look for broken parts, dirty wheels,
or something stuck in the gears), is bypass the decoder and test it on straight DC.
This is the only way to ferret out if the problem is pickup, something with the motor, the gears, or quartering (in the case
of a steam loco).  Leaving the decoder in the circuit will have you chasing your tail trying to figure out
if the problem is mechanical or related to decoder settings, or if there is a really serious mechanical issue that
the decoder is partially covering up for you. 

I am seeing an undesirable trend (like with the Bachmann Berkshire)
of people looking at a poor performing engine and starting first by messing around with CV settings.  That should never be
the first thing you do.  Make sure the darn mechanism actually works right first.  Then go after CV settings.

[Chinapig]

Well Jon, if the motor was wasn't faulty before I reckon it might be now as I had to heat the flywheels up in a gas flame to get them to come off the shaft

Excellent advice mmagliaro, it may have saved me a lot of aggravation as well as the cost of a new motor.

[peteski]

Max, what you said makes perfect sense. However, sometimes it is difficult to accomplish, but I agree that the DC operation should be the basemine on which to judge a model's performance.

In this instance the decoder was factory installed.  But some modelers might think that running a decoder-equipped (with sound) loco  to judge the performance of its mechanism and motor is a valid setup.  But the DC track voltage still gets processed in the decoder circuitry and more often than not, this degraded the overall DC performance of the model.  In most cases the motor is fed not DC but the PWM motor control pulses generated by the decoder (or the DC is modified in other ways).

The only correct way to judge the models DC performance would be to remove the decoder from the circuit and feed straight track voltage to the motor. One models like this that requires more or less severe modifications of the electric wiring.

Why did I mention all this?  Because someone might take your advice literally and try to run a DCC-equipped model on DC powered track and not get the results they expect.  While you did mention bypassing the decoder, I just wanted to really drive that point in.

So this is a heads-up to modelers who are trying to improve running characteristics of a model: remove the DCC decoder out of the circuit before judging the models DC performance!

EDIT: I also want to bring up another point (for DCC users).  If the loco in question has a smooth-running mechanism but the motor itself is not optimal (a straight-wound 3-pole motor with a fairly high starting voltage and some cogging in DC  for example).  If the DCC decoder controlling that motor has good motor-driving circuit  (good PWM output and good BEMF feedback circuit) so that it is able to run that motor smoothly from a crawl to full speed, to me that is a viable alternative to replacing the motor.