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Advice on rewinding an early postwar pulmor armature and field windings?

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  • Member since
    June 2023
  • 137 posts
Advice on rewinding an early postwar pulmor armature and field windings?
Posted by James Huff on Wednesday, July 24, 2024 9:25 PM

so my second side project is comp overhauling my 1954 Lionel 2245 texas special f3. I am now up to the point of rebuilding the horizontal pulmor motor and taking up the task of rewinding the armature and field windings, so I first checked the gauge of wire for the armature and it's 29 gauge copper magnetic wire, so I ordered from temoc 600 feet of 29 gauge copper magnetic wire since I going to work on the armature first. Now the first thing I want to know since this is my first time working with a horizontal pulmor motor, how do i take it completely apart and the armature apart? Does anyone here have any experience and tips rewinding a armature and pulmor motor field winding? I heard it's a very delicate process so I want to be careful and be sure exactly how and what I'm doing. 

  • Member since
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Posted by El Fixes Things on Wednesday, July 24, 2024 10:46 PM

I do not have experience re-winding these motors, and very limited experience rewinding motors in general (still working on learning). 

It sounds like you're already pretty comitted to doing it, but unless the windings are in any way shorted, leave an open circuit, or are otherwise damaged, I would not reccomend rewinding the motor as it won't offer you any benefit. 

That said, in order to get at the armature to re-wind it, the armature must be slid out from the motor at the end with the brush plate. The gear on the end of the armature shaft prevents you from doing this, so you will have to press or carefully tap the armature shaft out of the gear. You will also probably need to remove the commutator from the armature as it will get in the way of re-winding. After re-winding, you will need to press both of these parts back onto the armature shaft.

The field is harder- it's riveted to the motor casting. It's not meant to be removed. You would have to drill out the rivited ends to get it off so you could access the field winding well enough to remove the old winding and put in a new one. You would have to drill and tap holes into the posts that support the field, to replace the riveted ends that you drilled out to remove it. Physically possible, but fairly involved.

The main challenge with re-winding a motor, is making sure that your windings turn out tidy, even, and in the case of the armature windings, identical. You don't want any shorts to the armature shaft, and you want all your windings to be wrapped the same direction, with the same number of turns per pole.

Document the motor as you take it apart, with plenty of pictures. Manually unspool one of the armature poles carefully so that you can count how many turns it has. If you document the direction the poles are wound, and how they're wired to the commutator, it will make it simpler when you have to re-wind the motor in case you don’t remember how it was before.

All in all, I think this is a big project that you really needn't take on unless you motor genuinely needs a re-winding. It's pretty rare for a Lionel postwar motor to have a bad winding, odds are that any trouble you have with a motor is caused by any number of other possible faults. Unless you're pretty certain your armature and/or field has a bad winding, there's no advantage to replacing Lionel's factory work here with your own, aside from wanting the practice.

That's my perspective, at least. Good luck with your 2245, looks like it's sat with a battery in it for a little while.

-Ellie

  • Member since
    June 2023
  • 137 posts
Posted by James Huff on Wednesday, July 24, 2024 11:32 PM

El Fixes Things



It sounds like you're already pretty comitted to doing it, but unless the windings are in any way shorted, leave an open circuit, or are otherwise damaged, I would not reccomend rewinding the motor as it won't offer you any benefit.  

That's my perspective, at least. Good luck with your 2245, looks like it's sat with a battery for quite a while.

-Ellie

 

 

i know for a fact the motor is at fault because when I got it the original battery was indeed inside, which took a huge hit to everything except the actual horn relay. The motor caught on fire after gutting the acid and replacing the eunit, (the eunit was completely rusted and beyond repair) so yeah after checking my wiring i found that One of the wires connecting the motor to the eunit melted the insulation on the motor end, and the motor armature and field windings are a scorched black color. Luckily I didn't have the shell on when the motor caught fire. 

  • Member since
    January 2023
  • 131 posts
Posted by El Fixes Things on Thursday, July 25, 2024 8:20 PM

It might still be worth checking if you have any shorted windings, just in case they somehow survived the fire, but that sure does sound like a mess of a situation you have! You're probably right about a re-winding being neccesary. 

I wish you the best of luck with repairing the motor, it should come apart as far as it needs to for re-winding by seperating the parts I mentioned in my previous post (in addition to the usual steps of de-soldering wires to the brush plate, and removing the brush plate & brushes). Note that the field winding will probably have a different number of turns from the armature poles, so you'll need to count the number of turns for both the field, and one of the armature poles, to know how many turns of new wire to put on.

Technically you could probably use a good motor, a very accurate multimeter, and some math to calculate how much wire is needed for your new windings, but it's probably easier to just count the turns.

-Ellie

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