...Been working on my Silvertone 5731 Radio Recorder. Within the last couple of weeks I refinished the cabinet. I've had it since 1998, and use it almost daily. While it was in fair condition when I bought it, it became more and more worn out as I used it, and I finally thought it would be nice to give it a facelift. The cigarette burn on the lid still remains, but otherwise it looks great.

I was always proud of this set because I was able to use all of its original capacitors. A while back the electrolytic can went dry, and so I put in a new one, but all of the Solar capacitors were working fine. Two days ago I was noticing rather excessive distortion, though, and mushy volume, so finally I replaced all of the audio bypass caps. :( Made a great improvement in the audio. Very clear!

...The main purpose of this post, however, regards the motor. The motor always ran very hot on this phonograph. It will burn if you touch it for any length of time. A few years ago I decided to rewind it. Not only that, but I also separated all of the laminations and lacquered each one to further increase resistance and reduce eddy currents. I also increased the turn count of each coil by about 6 to 10 turns. I forgot how much, but enough to significantly increase the turn count of the entire motor.

Well, I put it all back together, and first it wouldn't spin at all. I was sure that a coil was reversed, so I reversed the wires of the coil that looked obviously reversed. It then ran, but was rather weak, and made a strange whirring sound that I've heard before in motors with a reversed coil. Well, not sure anymore what to do, and not wanting to play hit-and-miss with all four coils, I just put the motor back together and used it that way. It also still ran hot.

Well, last week I had had enough, and got the bright idea to use a battery to determine coil polarity. Not sure why it took me 2 years to figure this out, since I've rewound motors before and have even heard of some technique similar to mine, but I guess it's better late than never. I took a small magnet and hung it on a string, and marked it with a marker, since I can't locate my compass. For each coil I connected a battery with the + and - connecting to the wires of each coil in the same way as facing the coil from the outside of the motor, and I noted which way the magnet rotated. Once I determined the polarity of each coil, I wired the 4 of them so that two opposing coils were one polarity and the other two are the other polarity.

Now the motor works with excellent power and smoothness. Unfortunately it still runs very hot, so I never did solve my original issue. Shaded pole motors tend to run hot, though. They are very inefficient motors. Every shaded pole motor I own runs hot. ...But this motor runs especially hot. I wish there were a way to attach a fan to it. It has an internal fan, but it is hardly adequate.

Oh well. ...But if you are rewinding a multi-coil motor and are curious as to the coils' polarities, here's a method that will help.

T.

What about a small brushless fan like the ones they have in PCs ..When I rip apart old PCs I keep the brushless fans and use in my large display cases to keep hallogen lights cool

I have thought about it, and I may do that. I like to put as little modern electronics in my radios as possible, but it may come to that. The phonograph already has a modern Electro-Voice stereo cartridge. I got sick of the thumb screw cartridge eating up my records and not having good vertical noise cancellation. ...So I tolerate a modern cartridge It has fairly stiff tracking forces, so it isn't too delicate, but it's very delicate as far as 78s are concerned, and it's fitted with a diamond needle that sounds great and just won't wear out.

...So ya, I may put a fan in there. Perhaps, also, I could mount a small one on the bottom of the shaft, as there seems to be enough room for one, but I bet it would be no more effective than the one on top that's mounted to the rotor.

The motor in my reel-to-reel tape player has a more effective fan mounted to a shaft that extends out the rear of the motor. That motor gets hot, too. I also have a motor that I pulled from a junked tape player that is almost identical to the GI motor in my Silvertone, and it, of course, gets very hot, and did have a fan mounted to it when it was in the tape player.

Split phase motors are so much better. My 1908 Westinghouse has a split-phase motor with a centrifugal switch. The motor has tons of power and barely gets warm. It consumes a mere 60 watts! The fan puts out the same amount of air as my more modern (1910s and 20s) shaded pole fans, which draw from 86 to 100 watts! (and they get hot)

T.

T.