[ARC5] Power supply suggestions

[Michael Hanz]

"Paul H. Anderson" wrote:
> Two things to ponder - the goo that remains dried out in bearings -
> sometimes I think it may just be better to flush it entirely.  You can add
> new solvents, but it just delays the problem, I think (note I haven't
> tried Mike's suggestion of Mobil-1 in a bearing yet).  The reason I say
> this is that if the unit is used and the grease is that dry, that by that
> time, who knows what other crap got into it.

Absolutely!  However, as a student of the human condition, I well
understand the urge to see something work 'right now'.  That's why I
suggested adding a few drops of a good thin lubricant to each bearing if
you just "gotta see it run."  That in no way implies any license to
leave it that way for continuous use.  It will give you a grace period
that will vary depending on the condition of the original grease, but is
not a permanent solution for the reasons you describe.

> I'm trying to track down bearings for my R-391 autotune motor, which at
> 28V has at least that in common with the dynos.  Stupid autotune motor has
> two different non-standard bearing sizes.

Non-standard means a lot of different things.  If you go to a good
bearing house with the right info, you'll be surprised at what they will
consider a stock item.  Look in the yellow pages and unless you're in
the boonies there will probably be one in your area.  If not the
internet will provide a plethora of them.  Here's a quick rundown on
what you need to give them:  Internal and outer diameter; thickness at
the internal diameter (and at the OD if different); flanges (if any);
single or double shields, or seals (ask about sealed bearings - they may
have them); any part numbers on the old bearing you can find; and
rotational speed.  Very often they can cross reference the old part
number (even one 50 years old) so that's the best start.

> One point may be that a bulk purchase of bearings
> known to be good for DM-32A dynos might be a good idea (likewise for R-391
> autotune, but that is another issue).  

Not a bad idea.  Doesn't have to be Chinese to get a decent price. 
ABEC-1 class bearings are all that are necessary, thankfully.  Be
happy...I'm looking at shelling out $600 for two ABEC-7 bearings for my
Hardinge toolroom lathe.

> The reason new bearings is appealing is that if the bearing is pre-lubed
> double shielded, getting the shields off is a PITA, and I personally think
> relubing is only going to postpone the inevitable.

> One question I have is - are the DM-32A bearings double shielded, or
> single?

The originals in the ARC-5 dynos are only single shielded, but they are
a very common size.  I suspect you could get a fully sealed bearing with
wipers for less than $10 each - very likely half that depending on how
nice you talk to the counter man.

> I'd be willing to help contribute to a FAQ for ball bearings and brushes -
> there must be others that know a lot more about it than I do, though.

At the risk of being immodest, I might suggest the two-part article in
the April and May 1997 issues of Electric Radio as a starter.  You can
extrapolate from there.

73,
Mike