[ARC5] Re: [MRCA] BC-348 Dynamotor Temp.

[WA5CAB at cs.com]

I agree with Lenox, with this caveat.  All of the WW-II era dynamotors that I 
have actually owned have open bearing.  Some of the mid-50's and later ones 
don't.  Specifically, the DY-17A/ART-13 has double shielded double sealed 
bearings.  You can actually re-lube these but to do so you have to permanently 
remove one shield and seal from each bearing.  And then depend upon the bearing 
cap to keep grease out of the end-bell (which it should do OK).

One other thing you should always do before lighting off a new to you 
dynamotor for the first time is remove the brush caps and make sure that no brush is 
stuck in its holder.  It isn't necessary or even desirable to completely 
remove the brush.  Further, when doing this use one of those rubber-strap wrenches 
if you have one and if it will fit on the brush caps and if you can't loosen 
the cap with your fingers.  Avoid using a screwdriver in those caps with a 
screwdriver slot.  All too often, at least once during the operation, you'll split 
a cap.

Anyway, a newly acquired dynamotor with a stuck brush will probably appear to 
run OK initially.  The brush will have been in firm contact with the 
commutator when it decided to stick.  But after a little wear it will go intermittent 
and may damage the commutator in the process.

In a message dated 4/17/2008 5:49:28 PM Central Daylight Time, 
radios at sbcglobal.net writes: 
> FYI, I never run a dynamotor without first disassembling it, cleaning the
> bearings, and relubricating them with an appropriate, modern lubricant.  I
> have never found this to be a difficult operation.  You can remove the end
> bells, hold the dynamotor, one end down, over a tray of solvent and use a
> small brush to clean the bearings.  Don't let the solvent get on the
> brushes, wiring, commutator, etc.  Lubricating is easily done with a flat
> toothpick which will allow you to get the lubricant down between the balls.
> Just be sure you don't use too much lubricant and don't get it on the
> commutator or brushes.  Do the same to the other end and you've got it.
> 
> P.S.  I have never found a WW-II era dynamotor where the original grease was
> still good so don't run them without fresh lubrication.

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
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