[ARC5] Dynamotor prep?

Mon, 31 Mar 2003 13:08:19 -0500

At 10:26 AM 3/31/03 -0500, Beckley, Stew wrote:
>Greg,
>For the first spinup to a 28V dyno, I put it to 12V. If it cranks OK, then 
>I take it to 24-28V. I have no scientific basis for this, other than going 
>easy on it for its first spinup in perhaps 4-5 decades.

Two opinion bits from me on Dynamotors:

1) do not run one for long with old grease.  at the very least, get a drop 
of new oil into the old grease to loosen it up.  All new grease after 
thorough cleaning is best.

2) do not under any circumstances use sandpaper on armatures. The grit can 
get embedded in the copper and wear the brush down to nothing very soon.

Here are a couple of messages from earlier (Jan, 2002) about dynamotors:

>From: "Ian E. Abbott" <[email protected]>
>To: <[email protected]>
>Subject: Re: [ARC5] Power supply suggestions
>
>Hello-
>
>I'd just like to encourage anyone who's interested in dynamotors to find the
>articles that Mike Hanz wrote for Electric Radio- see below from his post. I
>found them to be *very* informative, and recommend them highly.
>
>MSC industiral supply carries the Mobilith SHC-100 grease that Mike
>recommends for dynamotor bearings. It's designed for high speed ball
>bearings in electric motors. It's part number 60002623,  priced at just
>$5.95 for a grease-gun sized tube. You can reach MSC at (800) 645-7279.
>
>(I have no connection with Mobil or MSC, I'm just a customer.)
>
>Cheers,
>
>Ian Abbott
>[email protected]
>
>
>----- Original Message -----
>From: "Michael Hanz" <[email protected]>
>To: <[email protected]>
>Sent: Wednesday, January 16, 2002 2:46 PM
>Subject: Re: [ARC5] Power supply suggestions
>
>
>(lots of stuff snipped)
>
> > 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.
>
>From: "J. Forster" <[email protected]>
>To: [email protected]
>Subject: Re: [ARC5] Cleaning ball bearings
>
>Here are a few observations about bearings.
>
>The grease may be old, but may well not be either oxidized or dried out. Check
>before you proceed  further.
>
>Bearings that are shielded often have the shields retained by circlips made of
>fairly thin wire. These can be removed with the tip of a sharp knife and 
>replaced
>after cleaning. Do not remove the ball retainers.
>
>Bearings can be cleaned by soaking in a solvent. Possible choices are 
>Goof-Off,
>WD-40, kerosine, trichlor, or acetone. Some are flamable or toxic so be 
>careful. An
>ultrasonic is really good for cleaning bearings. I've seen small ones for 
>dentures
>that'd do nicely. Also, you can put the bearings and solvent in a small 
>plastic bag
>to keep the cleaner from getting dirty. Use at least 3 changes of solvent, 
>each in a
>new bag. The last rinse should be with very good, clean solvent. Dry in a 
>dust free
>environment.
>
>BTW, if the ball retainer is plastic, be VERY careful with the solvent you 
>use. It
>can be damaged or crazed by the wrong solvent.
>
>When clean and dry, the bearing should spin extremely freely and quietly. 
>If it does
>not, try some more cleaning.
>
>The grease should be compatible with the ball retainer, if it's plastic. Don't
>overpack.
>
>Re-assemble in a clean place.... no grit, etc.
>
>Good luck,
>John

Roy

- Roy Morgan
National Institute of Standards and Technology
100 Bureau Drive, Stop 8970
Gaithersburg  MD 20899-8970
Voice: 301-975-3254  Fax: 301-948-6213
E-mail:  [email protected] --