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Re: (ET) Ryobi 2400
Rebuilding a motor is not a big deal.....here's an old article that was
sent a while ago......
Disassemble the starter\Alternator & remove the brushes. Look at the
commutator bars (segmented piece where brush rides with "mica insulation
strips" separating each bar). Check the stator & armature windings for
broken windings and flaking\nicked varnish coatings. Polish commutator
bars with emory cloth (don't use sand paper or steel wool!!) Wash stator
& commutator in hot soapy water. Blow off as much water as possible.
Obviously, compressed air works the best. Using a cookie sheet or pie
tin, place each of these in your oven (wife really appreciates this part)
set to 220 degrees MAX!!! This will bake the moisture out of the
windings. Leave in for 2 to 3 hours, remove and allow to cool to ambient
temperature (this is important!!).
Test with armature\commutator with Ohm meter from bar to bar. Meter
should read max resistance or very close to max indicating that there are
no bar to bar shorts. Check from each bar to armature shaft, again max
resistance, indicating no bar to ground shorts. Check the stator winding
by testing the leads to stator frame for ground, again maximum ohms
resistance should be present If the resistance is very high, this is an
indication that no "mechanical" shorts exist.
As the brushes ride on the commutator bars, the commutator bars begin to
wear along with the brushes. Once the commutators bars wear to the point
that the Mica insulation strips are even with the top of the bars, this
causes intermittent contact between the brush and the commutator. If this
is a starter, this will cause a "flat" spot if the brushes land on the
mica insulation strip and not on the commutator bar. Sometimes you can
tap the starter and it will turn. On an A\C alternator or DC Generator
this will cause the unit to reduce output or stop charging completely.
This next step will describe how to undercut the mica insulation strips so
that they are below the commutator bars. Wrap the end winding with
several rounds of tape to protect from damage to the insulation which is a
varnish coating. On a small commutator, use a utility knife and scrape
the top of each of the mica insulation strips until they are about 1/32 to
1/16 inch BELOW the commutator bars (with the knife blade parallel to the
mica insulation, pull the knife toward you away from the winding and
patience is the key). Blow off any insulation and brass\bronze metal
filings and recheck bar to bar & bar to armature shaft resistance (Should
be Max resistance). On a larger commutator, a hack saw blade works great
to undercut the mica insulation. If you have an industrial supply house
in your locale, you can purchase winding insulating paint. If not, I have
used High Heat Engine paint as a substitute. Remove the masking tape from
the commutator windings. Next tape the commutator bars and brush holders
with masking tape. Apply a couple of coats of paint to the armature &
stator windings. This will cover any insulation (varnish is used on most
windings as insulation) that may have been nicked or flaked off from heat.
Install new brushes & bushings as required and it should work like new.
....Walt
Erie PA
-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu]On Behalf Of Joel Parks
Sent: Thursday, May 10, 2007 6:29 PM
To: Ron Blair; Elec-Trak email list
Subject: Re: (ET) Ryobi 2400
Hi Ron,
I'm copying this to the elec-trak list because I don't know who else would
know.
I imagine it would be cheaper to have a motor shop put new bearings and
otherwise rebuild your motor than to buy a new one. Unless Ryobi would
sell
you the part
Can anyone help with Ron's question?
My Ryobi BMM 2400 seems to have been appropriated by a friend. Anyway I'd
keep it.
best,
Joel
----- Original Message -----
From: "Ron Blair" <rbi lisco com>
To: <et jpjt net>
Sent: Thursday, May 10, 2007 12:24 PM
Subject: Ryobi 2400
Hi Joel,
Found you on internet. I have a beloved BMM 2400 and I just lost the
motor. Do you know of any place to purchase parts? Would you sell
your 2400?
Thanks,
Ron
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