[Boatanchors] [Milsurplus] vintage motor winding question

hwhall at compuserve.com hwhall at compuserve.com
Wed Sep 18 20:46:47 EDT 2013 

 I located a copy of the original patent for the motor. And, yep, there is only a single slit per lamination. Apparently, each was flexed slightly to shove a leg through the winding bobbin, then the lamination was allowed to spring back flat. Modern laminations appear to all use an "I" section over which the bobbin is slipped and then the "I" slides into the rest of the frame to complete assembly. So I'd have to disassemble the entire motor and frame to get the winding bobbin free, then remake the whole thing. Could be done if desperate, but yikes that's a lot harder than I thought it'd be.

Thanks for all for offers of info & suggestions!

73,

Wayne
WB4OGM

 

-----Original Message-----
From: J. Forster <jfor at quikus.com>
To: hwhall <hwhall at compuserve.com>
Cc: milsurplus <milsurplus at mailman.qth.net>; boatanchors <boatanchors at mailman.qth.net>
Sent: Wed, Sep 18, 2013 5:10 pm
Subject: Re: [Milsurplus] vintage motor winding question

 
 
 
I looked at you pic and could not see any breaks in the lamination. 
 
Because of the construction it will be nearly impossible to rewind the 
coil w/o drilling out the rivits. And, if you do drill them, I suspect it 
will be pretty hard to reassemble the thing properly. 
 
My *guess* is that cutting off the existing winding and replacing it with 
something like #18 to #20, hand wound, and using a transformer would be 
your best shot. 
 
Good luck! 
 
-John 
 
==================== 
 
 
 
 
 
 
> Actually, here's how the laminations look on one side: 
> ||          || 
> =========== ======= 
> =================== 
> =========== ======= 
> =================== 
> =========== ======= 
> =================== 
>  ||<-rivit-> || 
> 
> On the other side they look like: 
> ||          || 
> =================== 
> =========== ======= 
> =================== 
> =========== ======= 
> =================== 
> =========== ======= 
> ||<-rivit-> || 
> 
> If you look at that top lamination's gap, then run your eyes all around 
> the motor, looking at that same lam with a magnifying glass, you arrive 
> back at the same gap without seeing another one. IOW, it appears each 
> lamination is a single plate with only a slit in it at one point. But that 
> would be nigh impossible to manufacture. They wouldn't have been able to 
> thread them through the winding bobbin. 
> 
> Wayne 
>  WB4OGM 
> 
> 
> 
> 
> 
> -----Original Message----- 
> From: J. Forster <jfor at quikus.com> 
> To: hwhall <hwhall at compuserve.com> 
> Cc: milsurplus <milsurplus at mailman.qth.net>; boatanchors 
> <boatanchors at mailman.qth.net> 
> Sent: Wed, Sep 18, 2013 4:08 pm 
> Subject: Re: [Milsurplus] vintage motor winding question 
> 
> OK. I would GUESS the laminations are interleaved: 
> 
>   ||          || 
> =========== ======= 
> ===== ============= 
> =========== ======= 
> ===== ============= 
> =========== ======= 
> ===== ============= 
>   ||<-rivit-> || 
> 
> If you remove the rivets, you can probably pull the laminations out 
> one-at-a-time, unless the shading coils exclude that. 
> 
> Some possibilities: 
> 
> Strip the winding and rewind it using a circular bobbin, like a torroid 
> winding machine. 
> 
> Strip thye winding and rewind w/ something like #22 which is easier to 
> handle and will have FAR fewer turns, then put a step-down transformer in 
> between the line and motor. This approach will take some calculation, but 
> it's not complex. Basically you are 'converting' the motor from 115VAC to 
> some lower voltage at a higher current. I's pick winding parameters so a 
> 6VAC filament transformer is correct, because they are common as dirt. 
> 
> Running it w/ reduced turns is asking for trouble, IMNSHO. 
> 
> -John 
> 
> ============== 
> 
> 
> 
> 
> > Yes, it is an AC motor and the frame is like you described it. 
> > 
> > I'd be willing to rewind from scratch if I could pull the bobbin, but 
> the 
> > stator frame is riveted together. In the frame at either end of the 
> > winding bobbin, I can see gaps in each lamination, but only one per 
> > lamination (I've looked all over the frame for other gaps), and they 
> > alternate. I.e., the top lam shows a gap on the left side, the next 
> lam 
> > shows a gap on the right, etc. So, I cannot see how they assembled it 
> in 
> > the first place, or how I might pull the frame apart to remove the 
> bobbin. 
> > Unless the "missing gaps" are hidden under the winding bobbin. 
> > 
> > I've peeled 200 turns off & seem to be past the worst damage. I'm 
> thinking 
> > I might be able to use a solenoid coil like a motor "growler". If I 
> can 
> > put a mag field into the frame, a shorted turn might show by causing 
> a 
> > hacksaw blade to vibrate if touched to the frame. At least, something 
> like 
> > that is the theory for a real growler in a motor repair shop. 
> > 
> > We may be able to locate another motor, but they are a limited 
> commodity 
> > as you can appreciate. If we can learn to fix one, we may one day 
> save a 
> > few more. 
> > 
> > 73, 
> > 
> > Wayne 
> >      WB4OGM 
> > 
> >  -----Original Message----- 
> > 
> > From: J. Forster <jfor at quikus.com> 
> > To: hwhall <hwhall at compuserve.com> 
> > Cc: milsurplus <milsurplus at mailman.qth.net>; boatanchors 
> > <boatanchors at mailman.qth.net> 
> > Sent: Wed, Sep 18, 2013 2:07 pm 
> > Subject: Re: [Milsurplus] vintage motor winding question 
> > 
> > I assume this is an AC motor? Is the winding basically a solenoid on 
> a "C" 
> > shaped, laminated iron, core, with the motor armature in the gap of 
> the 
> > "C"? 
> > 
> > Actually, it doesn't matter that much what the structure is. If a 
> winding 
> > is burnt, it's finished. 
> > 
> > What happens is a few turns touch, the insulation fails, and you get 
> > shorted turns. 
> > 
> > The shorted turns act like a shorted transformer secondary and heat 
> up. 
> > This promotes more failures and pretty soon the whole thing is toast. 
> > 
> > Aside: I've seen shorted turns causing a winding to glow dull red. 
> > 
> > Strip it all off and start new, IMO. 
> > 
> > -John 
> > 
> > =============== 
> > 
> > 
> > 
> > 
> > >  Hope this is not too far off topic. 
> > > 
> > > While working on a Link Trainer restoration, the winding on a 
> simple 
> > small 
> > > shaded-pole motor went up in smoke. It's 1940-ish vintage and 
> > resembles 
> > > the traditional record-player motor or small desk fan motor. 
> However, 
> > it 
> > > is not easily replaced by a modern motor due to parts of a gear 
> train 
> > > being mounted on it. I'm peeling off turns hoping the damage is 
> in 
> > top 
> > > layers and a partial rewind may repair it. 
> > > 
> > > My question is, when I think I've gotten past the burnt turns, 
> and 
> > have DC 
> > > continuity through the winding again, is there a way to detect 
> > whether 
> > > there may be any shorted turns in the remaining part of the 
> winding? 
> > All I 
> > > can think of right now is to see if it overheats rapidly. Is 
> there 
> > > anything else to look for? 
> > > 
> > > TNX & 73, 
> > > 
> > > Wayne 
> > > WB4OGM 
> > > 
> > > 
> > > 
> > > ______________________________________________________________ 
> > > Milsurplus mailing list 
> > > Home: http://mailman.qth.net/mailman/listinfo/milsurplus 
> > > Help: http://mailman.qth.net/mmfaq.htm 
> > > Post: mailto:Milsurplus at mailman.qth.net 
> > > 
> > > This list hosted by: http://www.qsl.net 
> > > Please help support this email list: 
> http://www.qsl.net/donate.html 
> > > 
> > > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> 
> 
> 
> 
> 
> 
>

More information about the Boatanchors mailing list