Re: OT-how to test and repair DC brushed motors.
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They don't have the brushes I need, nor do they have anything I can cut down to fit. Brushes are 5/16" square, approximately 5/8" long carbon block, and approximately 3/4" spring & braid. Looks like Leeson uses this style of brush, now I just have to find someone who carries Leeson brushes for a reasonable price.? One place that makes replacement brushes wants about $20 each, minimum order of 10.?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Friday, August 11, 2023 at 01:28:30 PM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:
Found a new place I can get brushes the other day, so put new brushes in the tool post grinder, and got the new power cable for it built, but been distracted ever since. Once I get home from this extended CF of a trip, I'll make a run with the old brushes to Evans Hardware. Ace here no longer carries brushes.
Lift has been in storage since her back got fixed and pulled her out of the power chair a bunch of years ago. Just put it back in service in December. Wouldn't be at all hard for it to have corroded the braid or spring or both. Stretching them to get them out, and putting them back in could have gotten me enough contact to spin it. Will check the brushes in the other motor too.
Thanks, Jon!
Bill in OKC?
William R. Meyers, MSgt, USAF(Ret.)
Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY!
Expect in one hand, expectorate in the other. See which one gets full first.
On Friday, August 11, 2023 at 12:44:18 PM CDT, Jon Elson <elson@...> wrote:
On 8/11/23 11:02, Bill in OKC too via groups.io wrote: SWMBO' s power wheelchair lift crapped out the other day.
New motor is no longer available since the lift is
ancient. Manufacturer of the lift removed any OEM
markings. It's a right- angle gear motor, which I'll
eventually have some photos and dimensions for. This is
the in-and-out motor for a Harmar AL-600 lift that fits in
the back of a van. Near as I can remember it was made
about 2007 or so.
There is no continuity in the motor, but? othinf seems
burned. I pulled it apart and fiddled with it, and got
continuity back. Hooked it back up to power trying to get
a current draw reading and it spun up and? rapped out
again. No continuity again. Brushes look good. Well, two possibilities.? One is the brush springs are shot and don't hold the brushes against the commutator.? On a lot of motors, if the copper braid that is supposed to carry the current gets corroded, then the current goes through the spring, that fries the temper. This is fixable.? Amazingly, it has screw-in brush caps! Another possible situation is there is an open winding in the armature.? You can check for this by applying a very low voltage, like maybe a single D cell to the motor, and see if it pulses and pauses.? That is not really easy to fix. That looks like a REALLY standard motor, but likely it has a special shaft end with the worm machined into it. Jon
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Bill in OKC too