# A long and winding road- armature winding, that is-



## AFnewbie

As a very brief intro- after support from this S scale forum, from Tom Barker and from my son the EE; after much electrical testing and learning how to test better, I've finally committed to rewinding the armature for my 343 steam locomotive. I know it's not rocket science and it's not as quick as buying a replacement part, but I've always enjoyed puzzles and problem-solving. And if I crash and burn- then I'll buy the replacements. 
But be forewarned- I readily admit to over-analysis. So, if you'd like to come along, I welcome any and all input. If you're really bored and want some background on what got me to this point, see my thread "343 switcher power, or not-".

I'll start with some 'before' notes and pictures, (photos-armature 1 and armature 2), then I'll capture and post key steps along the way. 

After gently removing the thin glue layer between the field poles with an x-acto knife, I could see a soldered wire-twist laying in one of the gaps. (photo- armature splice). I was able to gently lift up this splice with a toothpick (photo- pigtail or not). While it looks like 3 at the back, it only looks like 2 wires twisted together at the tip. I'll assume for now that it's the 3-pole pigtail, but I'm not 100% positive. For testing purposes, I refer to this wire-splice as P for pigtail. With this pigtail now accessible, in addition to basic commutator point testing, which I refer to as A, B, C, I was able to test resistance from the assumed pigtail to the commutator connection points.

Primary resistance testing- 
(Tom Barker's book calls for 1-2 Ohms across each pair of commutator points. So, in a good armature, I would expect to have 1/2 that resistance from P to each commutator point.)
My resistance readings in Ohms were- (+/- some level of meter accuracy) 
A-B = 0.5, A-C = 0.5, B-C = 0.2 
P-A = 0.4, P-B = 0.1, P-C = 0.1
Clearly, something is wrong- especially after I tested a new freestanding 12 ft length of 26 gauge wire, which registered 0.5 ohms. 
Another test- There was no continuity between any winding and the shaft or the field plates. That's as it should be.
My final "that's not good" test, that reinforced my decision to rewind, showed continuity between the commutator points and a section of windings where the dark colored enamel had worn (or been burned) away. (photo- armature short location).

More to come-
Paul M


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## tjcruiser

This doesn't answer your specific questions, but here's a simple wiring diagram of a 3-segment armature / commutator. It's shown for a DC motor, but the logic is the same of an AC motor.










From coil arm to coil-arm, does your wiring follow the layout above?

TJ


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## AFnewbie

If I understood that diagram, I might be able to answer. 

I have begun the surgery and am doing testing as I go.


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## tjcruiser

The little N-S rectangles each represent an arm of the armature coil. Wire wrapped around each. The dark-line 1/3 circles represent the one-third-segment copper armature face (commutator). So, the thine wire lines show you how the armature should be wired.

TJ


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## Nuttin But Flyer

If nothing else, you sure do take some real nice close-up photos.....


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## AFnewbie

tjcruiser said:


> The little N-S rectangles each represent an arm of the armature coil. Wire wrapped around each. The dark-line 1/3 circles represent the one-third-segment copper armature face (commutator). So, the thine wire lines show you how the armature should be wired. TJ


Thanks TJ. I think I get it from a logical perspective, but my physical wiring doesn't match exactly. I think mine is referred to as WYE connected vs. DELTA. See http://www.rfcafe.com/references/electrical/NEETS Modules/images/05311img11.gif

Next post begins my detail disassembly.


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## AFnewbie

*There's no turning back now-*



Nuttin But Flyer said:


> If nothing else, you sure do take some real nice close-up photos.....


Thanks for nuttin'- I'll try to keep up to the task. 
Photo references are as (P:attachment name)

First, since all 3 windings need to be in progress at the same time, I needed to devise some sort of rig to keep the wires under control. Here's my approach- I took the largest C-clamp I could find and super-glued faucet washers to the jaws, then secured the C-clamp vertically in a vise. I can tighten the jaws of the C-clamp just enough to hold the armature steady, allowing me both hands to maneuver the wires. But I won't need that for a while. (P:armature wiring rig)

I began the surgery by cutting the wire of the damaged winding from commutator point A and undid 2 turns. (P:clipped winding A)
Resistance from A-B or A-C = no continuity. Resistance from P-A = no continuity. As expected, point A is totally isolated.

I then separated the 3 wires of the pigtail and measured resistance- (P: pigtail ends)
Pigtail wires are numbered P1, P2, P3 from top to bottom
P1 to clipped winding A = 0.1, isolated from others
P2 to point B = 0.4, isolated from others
P3 to point C = 0.1, isolated from others
I'm not sure what I'll do with all these measurements, but I can't take them later on. 

I moved on to uncoiling the damaged winding A, trying not to break it, so I'm gently removing glue pieces with the x-acto as I go. (P:removing glue) After several turns, you can see that the protective enamel just flakes off. (P:unwinding 1). I'm curious to see how far I get before having to unwind the other coils.


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## tjcruiser

AFnewbie said:


> I think mine is referred to as WYE connected vs. DELTA.


Really???

I'm a Lionel guy, not an AF guy, so I have no direct experience with AF armatures. That said ...

If I look at your Wye diagram, that implies to me that the armature shaft is connected electrically to the armature windings, with the shaft itself part of the circuit. Is that really the case with AF armatures?

(On Lionel armatures, the armature shaft is isolated from the windings. The 3-segment commutator face does all of the in/out elec current work.)

Maybe I'm confused ... I would seem to me that the Delta setup (or better per my earlier diagram) is how the thing would be wired.

... says the guy in the 27th row of the peanut gallery ... 

TJ


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## AFnewbie

tjcruiser said:


> Really???
> 
> I'm a Lionel guy, not an AF guy, so I have no direct experience with AF armatures. That said ...
> 
> If I look at your Wye diagram, that implies to me that the armature shaft is connected electrically to the armature windings, with the shaft itself part of the circuit. Is that really the case with AF armatures?
> 
> (On Lionel armatures, the armature shaft is isolated from the windings. The 3-segment commutator face does all of the in/out elec current work.)
> 
> Maybe I'm confused ... I would seem to me that the Delta setup (or better per my earlier diagram) is how the thing would be wired.
> 
> ... says the guy in the 27th row of the peanut gallery ...
> 
> TJ


TJ-
Sorry if I misled you. The wires a definitely not connected to the shaft. There is an insulated core around the shaft where the windings are. At the innermost part of the windings, the three wires are pigtailed together.

Paul M


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## Nuttin But Flyer

WOW -- I am impressed by this project and completely attentive to the detail. I can't wait for the climax -- after all, someday we AF guys may all have to do this.


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## AFnewbie

Nuttin But Flyer said:


> WOW -- I am impressed by this project and completely attentive to the detail. I can't wait for the climax -- after all, someday we AF guys may all have to do this.


Thanks Don- Me either-

Getting these wires out from under the commutator housing is difficult. There's just no wiggle room- sort of like flossing between two tight teeth. 

Coil A broke after 2 windings, then again after a few more turns, seemingly overlapped by a winding from coil C. 

I then switched to coil C and I got about 5' off this one before breaking. This one was trapped under one of its own windings. Coil C's covering also flaked off, but not as much as A. 

On to coil B.
Unlike A and C, coil B was not burned at all and it came off intact and without too much difficulty. Off the armature, it measured 11' long with 0.7 ohms resistance. Hmmm- that's 0.2 ohms higher than my new wire-- We'll have to think about that. 

Now- back to the other coils. I've seen enough about the winding pattern, so if I have to just cut through them, it's no big deal.

I have interim photos, of course. I'll post them after all coils are off.


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## Nuttin But Flyer

Considering its age, I'm not at all surprised with it breaking and flaking. Hopefully the new wire will go on much easier as it should be more flexible. Then again, that could be a detriment to getting each wind layer tight.


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## AFnewbie

*Unwinding completed-*

First- If I still had a day job, I wouldn't quit it for this. I'd be broke in no time. 
I've included a photo of my work area. Note the headset magnifier. Without that, in addition to my bifocals, I wouldn't stand a chance. I also use plenty of light.

The photos tell most of the story, but to summarize- 
Throughout most of two of the windings, the enamel covering was blued and flaky and some wire was fused together, making for a slow, tedious removal process. After getting the one good winding off intact and seeing how it was wound, I first tried to cut through the other windings on the bottom using a dremel 1/64" cut-off wheel. BAD IDEA- it fused the wires as much as cutting through them. I reverted to my trusty x-acto and slowly got through a few wires at a time. 

Wish me luck with the wind process- but I won't be starting that for a day or 2- I need a break.


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## Nuttin But Flyer

First, a little history -- I obtained a box of 10 Atlantics at the York TCA show last year. I had all intentions of using them for the parts only as they appeared to be nothing m,ore thna junk. So when your issue arose, it seemed only fitting to check them for what you need and simply get yours as a trade and a new learning experience for myself later on when I feel ready to tackle such a re-winding project.

Now, the results -- Out of ten of these locos, several of them have the parts you need. Unfortunately, when I tried some of them on my track, they actually ran, albeit slowly or with noise. I have decided to keep some of these for repair/restoration rather than stealing the parts.

But -- the good news is I have one old rusted 300AC which has no tender and the correct motor parts you need. I have disassembled it and checked the armature. I got good readings across all 3 plates -- right around 1.7 - 1.8 ohms.  The field however is not giving me any result.  If I'm checking it correctly - one lead at each wire end?? The meter does not respond at all when I do this.

Are you interested??


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## Nuttin But Flyer

I also have a 307 with the same parts, that I'm willing to steal parts from with full intention of later obtaining replacement parts, or rewinding my own, to restore it.
I haven't checked this one yet, but the condition is pretty nice, so the field may be good in it. You interested in this one??


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## Nuttin But Flyer

Just in case you have mixed feelings about the 307, it needs a lot to restore -- a lot more than I have on hand. The tender is missing all the wheels and the truck sides are missing too. So it isn't anything I plan to work on sometime soon.

The offer -- both offers -- still stand. Let me know if you want these parts.

Meanwhile, I'm in the process of dissecting the 307 so I can check the field in it.
I'll post the results momentarily....


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## Nuttin But Flyer

By golly -- I'm thinking I might eventually cure a rainy day....but not in this bitter cold.

The field from the 300AC has been removed and restested and the results show it to be good -- reading 1.4 ohms.

Again, the offer stands. All you need to do is say "yes" and they will be on the way to you.


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## flyin-high

Hi, If you need help rewinding ANY American Flyer armature or field, please email me as I have a power armature/field wire winder. I've done many, many, possibly a thousand or more. Some of my customers have purchased more than 20 SUPER motors I manufacture. Thanks, Dave B. TCA #07-61760


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## Nuttin But Flyer

f-high - how do you handle this -- do you send out a traded good for an old one? how much do you charge?


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## AFnewbie

Nuttin But Flyer said:


> By golly -- I'm thinking I might eventually cure a rainy day....but not in this bitter cold.
> 
> The field from the 300AC has been removed and restested and the results show it to be good -- reading 1.4 ohms.
> 
> Again, the offer stands. All you need to do is say "yes" and they will be on the way to you.


Thanks Don- My answer is a probable YES. You have my email and home address; tell me how you want to handle cost and shipping.


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## AFnewbie

flyin-high said:


> Hi, If you need help rewinding ANY American Flyer armature or field, please email me as I have a power armature/field wire winder. I've done many, many, possibly a thousand or more. Some of my customers have purchased more than 20 SUPER motors I manufacture. Thanks, Dave B. TCA #07-61760


Flyin-high-
Along with NBF, I'm interested in your operating mode.


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## Nuttin But Flyer

First -- I...we, are here to help one another. I am not going to charge anything for this service. I'll gladly send them to you, I cover cost for shipping. All I ask is that you send similar replacements -- poor shape or good shape -- it matters not to me, some day. That way you get new, useable parts -- eventually, I'll get a replacement I can either use or rebuild as a learning experience.

Second, What I seem to be finding, is that both the non Pul-Mor and the Pul-Mor armatures are the same part number XA11077, at least in each service manual exploded drawings I have seen. The difference of course, is the close spacing between the armature poles v. the standard one. Tom Barker states that using the Pul-mor in a standard motor will cause additional current draw and damage the motor.

Third, the armature I have 'stolen' from my 300AC is obviously the Pul-Mor type with the close poles. Checking online, this engine did not come with Pul-Mor. So it seems this engine was re-fitted in some way. Therefore stealing the armature for your use seems more than ideal.

Last, just send replacement parts of similar type and I'll use them in my 300AC or some other loco, or I'll use them for a learning rewinding experience and we can call it even.

BTW -- While we are discussing this, does anyone agree that these two types of armatures have the same part numbers??


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## AFnewbie

Nuttin But Flyer said:


> First -- I...we, are here to help one another. I am not going to charge anything for this service. I'll gladly send them to you, I cover cost for shipping. All I ask is that you send similar replacements -- poor shape or good shape -- it matters not to me, some day. That way you get new, useable parts -- eventually, I'll get a replacement I can either use or rebuild as a learning experience.


Thanks Don-
You're very kind. I'm ambivalent about accepting your offer. If I'm successful with my rewind, I'll want to use my own handiwork, and I'll have nothing to send in return- at least not right now. 

That said, it might be nice to do some 'head-to-head' performance testing of original parts vs. rebuilt. See my PM

Paul M


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## flyin-high

Don, The price on rewinding your steamer armature is $25 and a diesel armature is $28. This includes resurfacing of the commutator. Customer usually sends me their armature to rewind. I do have in stock some re-manufactured SUPER motors (3/4 inches wide) for the steam engine priced at $130. If you were to send me 2 pul-mor motors to manufacture into SUPER motors, the price is $105. Rewinding of the steamer field is $18 and the diesel field is $22. Shipping is usually $4 to $5. Thanks, Dave B. email: [email protected]


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## Nuttin But Flyer

newbie -- your package is on its merry little way. barring the ugly weather, you should have it in a few days....hopefully if USPS stays on their toes.


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## AFnewbie

Nuttin But Flyer said:


> newbie -- your package is on its merry little way. barring the ugly weather, you should have it in a few days....hopefully if USPS stays on their toes.


Thanks Don. I'm looking forward to some head-to-head performance tests of an an original vs. my rebuild.

Re the rebuild-
I 'sort of' finished the winding. Because I didn't have a quick drying glue on hand, I decided to pigtail it on top, the way it was previously done, allowing me to glue after completing the winding. 

Just before I began winding , I received an email from Tom Barker with a link to his video on major engine repair. If you haven't seen it, you should- it covers e-units and smoke units as well as armature windings. He OK'd my posting the link here. http://tombarker.net/TomBarkerWebsite/Repair_Clinic_Movie.html 

After one bad pigtail solder, which I redid, I managed to wind close to 10 1/2 ft on each pole. I then epoxy-ed the pigtail and the gaps and will let that set before soldering the ends to the commutator and tucking the pigtail under the commutator. I'll certainly remove any excess epoxy from the poles before assembly. Pre-wind and post-wind resistance measured 1.0 Ohms across any two wire ends.

I was quite pleased with my rig. It secured the armature without stressing it and allowed me two hands to work the wire. I could keep reasonable tension on the wire as I wrapped it. I used a wooden presser stick where possible; otherwise I used a small screwdriver to press the windings tight in the gaps and at the top.

Hopefully tomorrow, it will be back on track.


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## Nuttin But Flyer

That's incredible. It looks great. I hope the results were worth it. I am getting the video as I write this and will store it on my computer for future use. Thanks for offering it to us.


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## flyernut

Nuttin But Flyer said:


> First -- I...we, are here to help one another. I am not going to charge anything for this service. I'll gladly send them to you, I cover cost for shipping. All I ask is that you send similar replacements -- poor shape or good shape -- it matters not to me, some day. That way you get new, useable parts -- eventually, I'll get a replacement I can either use or rebuild as a learning experience.
> 
> Second, What I seem to be finding, is that both the non Pul-Mor and the Pul-Mor armatures are the same part number XA11077, at least in each service manual exploded drawings I have seen. The difference of course, is the close spacing between the armature poles v. the standard one. Tom Barker states that using the Pul-mor in a standard motor will cause additional current draw and damage the motor.
> 
> Third, the armature I have 'stolen' from my 300AC is obviously the Pul-Mor type with the close poles. Checking online, this engine did not come with Pul-Mor. So it seems this engine was re-fitted in some way. Therefore stealing the armature for your use seems more than ideal.
> 
> Last, just send replacement parts of similar type and I'll use them in my 300AC or some other loco, or I'll use them for a learning rewinding experience and we can call it even.
> 
> BTW -- While we are discussing this, does anyone agree that these two types of armatures have the same part numbers??


If you go to post #69 of the 343 thread, you'll see I listed all the armatures that have the same part #.


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## flyernut

flyin-high said:


> Don, The price on rewinding your steamer armature is $25 and a diesel armature is $28. This includes resurfacing of the commutator. Customer usually sends me their armature to rewind. I do have in stock some re-manufactured SUPER motors (3/4 inches wide) for the steam engine priced at $130. If you were to send me 2 pul-mor motors to manufacture into SUPER motors, the price is $105. Rewinding of the steamer field is $18 and the diesel field is $22. Shipping is usually $4 to $5. Thanks, Dave B. email: [email protected]


Not meaning no dis-respect, but I can get a new NOS field coil for $10 bucks, and I've offered it up here on the forum.. Again, no dis-respect intended.


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## AFnewbie

*It's alive-*

After soldering the windings to the commutator and final resistance testing ( I needed another dab of epoxy on the pigtail), the unit was ready for bench test. It did not run-  

I never thought I'd be happy to see the inner wire of the field coil broken again, but I was. I guess it got too much jostling. Anyway, I think I did a better repair on it this time. I re-assembled and re-tested. It purrs like a kitten in both forward and reverse.  

I even had the joy of showing my 7 yr old grandson the inner workings of a locomotive and how to do continuity testing. 

Tonight or tomorrow I'll put it through some time trial on the track.


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## tjcruiser

Paul,

Great job on the rewind! You must have done a little "happy dance" when the thing first started spinning! Very clean work ... nice 'n tidy windings!

Hey, I recently got my kids a couple of "Simplest Motor" kits ... an easy-to-make and very simple functional electric motor that teaches kids (and adults) about what makes an electric motor run. Well worth a few bucks if you want to try something fun/easy with the grandson. See this thread ...

http://www.modeltrainforum.com/showthread.php?t=15219

And this product ...

http://www.amazon.com/TEDCO-Simples...qid=1359235058&sr=8-1&keywords=simplest+motor

Cheers,

TJ


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## Nuttin But Flyer

newbie -- Am I to understand you used your rewound armature and got her to run??


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## flyernut

Super


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## Nuttin But Flyer

flyernut - Yes I checked that list of engine numbers. What baffles me is according to specs I've found the 285, 290, 295, 315 and 354 do not have Pull-Mor. Yet these use the same armature P.N. as the other engines with Pull-Mor. We know that the Pull-Mor armature has the poles much closer together than on a standard one. If you look at the Gilbert manual, the armature P.N.'s are the same for nearly every steam loco they produced -- Pull-Mor or not. So I am either confused about the correct armature, or they used the same part number for both standard and Pull-Mor armatures.


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## flyernut

Nuttin But Flyer said:


> flyernut - Yes I checked that list of engine numbers. What baffles me is according to specs I've found the 285, 290, 295, 315 and 354 do not have Pull-Mor. Yet these use the same armature P.N. as the other engines with Pull-Mor. We know that the Pull-Mor armature has the poles much closer together than on a standard one. If you look at the Gilbert manual, the armature P.N.'s are the same for nearly every steam loco they produced -- Pull-Mor or not. So I am either confused about the correct armature, or they used the same part number for both standard and Pull-Mor armatures.


I believe they used the same armatures for either pul-mor or not. You start seeing different armatures as you progress through the k5 series and into the Hudson's.


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## Nuttin But Flyer

So getting that P.N. armature would not necessarily be the correct thing to do if your engine didn't have Pul-Mor. According to Tom's book, installing that in a non Pul-Mor engine will draw more current and eventually burn the motor. It is wise to have this knowledge when working on these motors. As an example, the armature I grabbed from my 300AC, found in a junk box at York, was a Pul-Mor type. Obviously it was incorrect since 300AC was not produced with that option. Someone must have re-fitted it incorrectly. Sure it probably ran, but for how long?? I will now be more cautious when buying items at train shows and eBay, or just be prepared to make replacements available in both types so whatever I acquire can be correctly fitted.


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## AFnewbie

tjcruiser said:


> Paul,
> 
> Great job on the rewind! You must have done a little "happy dance" when the thing first started spinning! Very clean work ... nice 'n tidy windings!
> 
> Hey, I recently got my kids a couple of "Simplest Motor" kits ... an easy-to-make and very simple functional electric motor that teaches kids (and adults) about what makes an electric motor run. Well worth a few bucks if you want to try something fun/easy with the grandson. See this thread ...
> TJ


Thx TJ. I peeked at that thread and will be back to it. I like the ideas.
As for a 'happy dance', when did you put a spy-cam in my basement-


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## AFnewbie

Nuttin But Flyer said:


> newbie -- Am I to understand you used your rewound armature and got her to run??


Yep, and when I first put it on the track, it 'flew'. It's still stripped down (no piston, smoke unit, linkages), but  nevertheless.

When your parts arrive, I'll do time trials with both sets as compared to the original rated specs. And I'll certainly ship them back to you if you think you can use them.


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## Nuttin But Flyer

I am flabbergasted and extremely pleased. You are a pioneer here with what you have accomplished -- at least in my eyes. Your work will go down in the annals of Gilbert history. OK maybe I'm going over the cliff with these remarks....and the enthanol I have been consuming over the last hour and a half is helping. Nonetheless, you are my new hero!! Do all the tests you wish. If and when you do return the parts...or replace, your choice...I will probably just drop them into my inventory for future use.

CONGRATULATIONS !!! Don't you now feel like Dr. Frankenstein?


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## Nuttin But Flyer

If it makes you feel any better about having my parts on their way to you, I found a complete junker 300AC in another box in my basement that I had no idea was there. Between the two I now have, it should be easy to make one complete runner. The project has already begun with a good tender cleaning before heading off to bed. Tomorrow, I start on the engine section. If all goes well, it should be running sometime later tomorrow. Let you know how it turns out.


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## AFnewbie

Nuttin But Flyer said:


> CONGRATULATIONS !!! Don't you now feel like Dr. Frankenstein?


That's "Frankensteen" -- glad you got the reference-


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## flyernut

Nuttin But Flyer said:


> So getting that P.N. armature would not necessarily be the correct thing to do if your engine didn't have Pul-Mor. According to Tom's book, installing that in a non Pul-Mor engine will draw more current and eventually burn the motor. It is wise to have this knowledge when working on these motors. As an example, the armature I grabbed from my 300AC, found in a junk box at York, was a Pul-Mor type. Obviously it was incorrect since 300AC was not produced with that option. Someone must have re-fitted it incorrectly. Sure it probably ran, but for how long?? I will now be more cautious when buying items at train shows and eBay, or just be prepared to make replacements available in both types so whatever I acquire can be correctly fitted.


Well, I'm kinda baffled.If Gilbert used these armatures in both pul-mor and non pul-mor, and experienced burned out motors, I would think that there would be some sort of service bulletin or something. That's a span of 7 years using the same armature.. I know there's a difference in the length of the shaft in some motors, but that's it.Who knows.


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## Nuttin But Flyer

My mistake....Tom's book did not say the motor would burn out, only that it would run slow due to excessive current draw.....

I need to learn how to read more completely.

Nonetheless, the Gilbert manuals do show the same P.N. armature used in both types of motors. I am surprised that Gilbert would not have issued different part numbers for the obviously different, and apparently non-interchangeable, armatures.


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## AFnewbie

*Time trial results-*

With the grandkids gone, and with a couple borrowed meters from my son, I ran my first time trials. 

Before getting to the results, I'll mention that my 342" oval track on rubber roadbed is loose laid on cardboard over the supporting ping pong table and some plywood, so it has a little bounce to it. Adding to that, the 343 locomotive wheels are a little out of true, so the train has some wobble and won't hold the curves at high speed. My testing was therefore done at lower voltage. 

For each test, I converted total distance traveled in one minute to 140" equivalent laps. I ran each test at the fastest 'safe' speed that I could. During each test run, voltage was measured on the track and current was measured at the transformer-to-track terminal wire. I get slightly different readings with different meters, so I don't attest to the utmost accuracy. Average results are below. (_Close enough for Gilbert work_) 

Spec: FWD, 12 Volts, under 1.55 amps, minimum 9 laps (140" oval)
Result: FWD, 08.5 Volts, ~1.3 amps, 9.5 laps (140" oval equivalent)

Spec: REV, 12 Volts, under 1.55 amps, min 8.5 laps (140" oval)
Result: REV, 10 Volts, <1.4 amps, 10.2 laps (140" oval equivalent)

Spec: FWD pulling 4 boxcars, 12 Volts, <2.1 amps, laps not specified
Result: FWD pulling 4 boxcars, 10 Volts, <1.8 amps, 8.0 laps (140" oval equivalent)

Bottom line- Even with meter inaccuracies, I think I'm well within specs. 

Next- I need to think about the smoke unit and how much 'prettying-up' to do. I'm missing linkages, etc.

Thanks for all your support and feedback. Here's the unit in action.


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## Nuttin But Flyer

That is absolutely beautiful...well done!!


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## tjcruiser

That's a happy motor, once again!


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## flyernut

Nice.


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## AFnewbie

*Winding takes another turn*



Nuttin But Flyer said:


> So getting that P.N. armature would not necessarily be the correct thing to do if your engine didn't have Pul-Mor. According to Tom's book, installing that in a non Pul-Mor engine will draw more current and eventually burn the motor. It is wise to have this knowledge when working on these motors. As an example, the armature I grabbed from my 300AC, found in a junk box at York, was a Pul-Mor type. Obviously it was incorrect since 300AC was not produced with that option. Someone must have re-fitted it incorrectly. Sure it probably ran, but for how long?? I will now be more cautious when buying items at train shows and eBay, or just be prepared to make replacements available in both types so whatever I acquire can be correctly fitted.


You all may recall that NBF sent me a spare armature and field a few weeks back. I finally tested his armature, which is identical to mine (oops- see update below), and it runs great. I initially did not install his field because I didn't want to disturb the one I had previously repaired. Well, as I was putting the loco back together today, my inner wire solder joint came undone- again. So, I decided to swap in Don's field. To my surprise, it's a little bit smaller than mine. My field has 18 plates, Don's has 14. Everything fit, but only when I removed the two fiber washers from the armature shaft. It seems to run OK, maybe a tad slower and with a slightly different sound. 

So, thanks to this Pul-mor discussion, my first thought is that Don's 14 plate field might belong with a non-Pul-mor armature. But then, could my 18-plate field be too large- and the cause of my armature burn-out in the first place? 
Does anyone know for sure? 

Either way, I'm planning to rewind my original field (which should be simple compared to the armature) 

Update: While the two 'identical' armatures are the same size, ~1/2" across plates, they also have a different # of plates. Mine has 13, Don's has 17. Sorry to mislead anyone. Now I'm really curious about proper pairing.


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## tjcruiser

I think you need the Field Guide to Fields for that one, 'Newb! Good question. No clue as to the answer on my end, but it's fun to follow your detective work!

TJ


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## Nuttin But Flyer

Wow, I never imagined there would be so many variables. What would a DC armature look like? Less plates, more plates? Would it work in an AC motor?

I wonder if the ones I sent were original with the engine I scavenged them?

I got a set of armatures and fields in an eBay purchase the other day and went throught them last night -- sorting, labeling and storing them. They all appeared to be the same with each other, but they do not match any of the others I have in my stock. They are very close but these "new" ones are missing the small center hub on the commuter side of the armature. Otherwise they appear the same. I did not consider counting the plates.
Unfortunately, there are no part numbers to ID them. The exploded drawings mention the use of a different armature assembly #XA9569 to be used with 1/16" washer. I wonder if these "new" armatures are these?

I guess if the width of an armature matches the field width, you may be alright. However, if the plate thicknesses and quantity must match, then that is a different matter.

Hopefully someone with an electrical background may be able to give us a lesson.


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## AFnewbie

Nuttin But Flyer said:


> I guess if the width of an armature matches the field width, you may be alright. However, if the plate thicknesses and quantity must match, then that is a different matter.
> 
> Hopefully someone with an electrical background may be able to give us a lesson.


I have partial answers from a non-train 'motor expert' - 

About the armature differences, he says- "Number of plates is not important to speed and torque and only affects "eddy currents". This plate thickness difference you have should have negligible impact on performance if the overall stack lengths are close. In general, the thinner the plates, the less eddy current, which is good. As an analogy, eddy currents are the electrical equivalent of those little whirlpools you get when you pass your canoe paddle through water." 

About the size difference of the fields, (0.58" vs. 0.45"), he says- " this also should make little or no difference and the parts would have little effect if interchanged."

That said, I think both Don and I are interested in what the train people have to say.


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## Nuttin But Flyer

What about a DC armature? What differences are there and are they interchangeable with an AC one provided the size is relatively the same?


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