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Re: OT-how to test and repair DC brushed motors.
I called Capitol Electric a couple of weeks ago. Talked to Mark. Said they didn't do DC motors anymore, and didn't know anyone in the area who still did. I guess the cheap import motors aren't worth working on...? My boss at the laundry always bought new motors when one had problems. Was of some benefit to me as a lot of the ones that weren't absolutely fried followed me home so they wouldn't have to pay to have them hauled away. Only exception was the 60HP 3phase motor. They had that overhauled a bit in place, and then replaced it outright when it crapped out again six months or so later. That one had about half a ton of copper wire in it, and the seller of the replacement wanted it back. I'm not sure I could have gotten thing thing in the back of my pick up anyway. 800lb motor, it was.? 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! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Wednesday, September 6, 2023 at 01:18:09 PM CDT, rockindubya via groups.io <jeffwoods95@...> wrote:
Bill, Just about any starter shop can growl them for you. As far as larger facilities go,? if Ron is still at Capitol Electric, tell him Jeff from Warfield and Chapman said hello. All the guys i knew at Evans Electric and Southwest Electric are retired or ...really retired... Jeff In Lone Star, TX |
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Re: OT-how to test and repair DC brushed motors.
I already polished them, and had the motors reassembled, minus the brushes. The bigger motor works fine on the bench. Likewise the smaller motor. Maybe I won't worry about the contact cleaner on the commutators after all... Going to see if I can get the lift put back together, and see what happens!? 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! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Wednesday, September 6, 2023 at 01:07:21 PM CDT, rockindubya via groups.io <jeffwoods95@...> wrote:
Bill, they both look serviceable, as is. Really no need to polish, as there is minimal grooving. That said, I have seen some emery paper that is actually electrically conductive. Crocus cloth has a biding agent for the rouge that will attract carbon dust as the brushes wear. Both are bad news, creating possibilities of a short bar-to-bar. (That's what the brush does momentarily, until they contact the next segment, and so on...) Aluminum oxide is non-conductive electrically. When I referred to polishing, I meant chuck it in the lathe, and spin it about 500-700 rpm and polish it while rotating. You want it as round as possible. Concentric to within .002-.004 T.I.R. is mostly acceptable. One high bar, or two directly opposite each other could mean a stall condition, but I see no evidence of that in your pics. A low bar, burned and pitted at the slot, possibly less so directly opposite, if at all, indicates an open coil (usually at the coil-to-comm connection, called the riser.) Any of these conditions will cause arcing when the brush makes and breaks contact with the comm, leading to rapid brush wear and decreased performance. In other words, if the opposite sides look as good as this side in the pics, you should leave them alone. The brown film you see is a good thing. that actually is a conductive deposit from the old brushes and no real need to disturb,(unless it is OOR) Did you locate your brush caps? Generally the brass ones are used to create a current path plastic might not provide. In a pinc, one coul use a brass washer between the cap and spring to accomplish the same thing... Jeff in Lone Star, TX PS. I'll post a couple pics of what I was referring to later. It's 105 in my shop, and I am DONE for today! |
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Re: Back Gear Pin & Rattle
I've got caps from the tool post grinder that seem to fit well enough. Will be using that. But I want proper caps for long-term use. Not sure what the original caps are, just some sort of dark gray or black plastic. Could easily be ABS. The tool post caps are brass. One solid, cut from hex stock, the other a brass cap with a plastic overlay on the cap. Since those are exposed on the tool post grinders, I'm going to want them covered with plastic, too. The motors are 120V universal, so 120VDC or AC. I have a habit of putting my hand on the tool post, so I could see that biting me... 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! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Wednesday, September 6, 2023 at 01:03:10 PM CDT, mike allen <animal@...> wrote:
Push comes to shove for testing a guy could make some caps that slide in the cap holes & hold them in with a hose clamp to test run the motor , animal On 9/6/23 9:38 AM, Bill in OKC too via
groups.io wrote:
IMay run to Metals
Supermarkets and see if I can find a stick of brass close to
the right size... Just in case the brush caps I ordered
don't fit. Though I have a stick of 5/8" Delrin impregnated
with Teflon that I could use, and not have to travel or
spend more money if I can find it. ;)
William
R. Meyers, MSgt, USAF(Ret.)
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Re: Should be OT: Motors... Back Gear Pin & Rattle
The commutator on an armature gets turned when it's clogged with carbon or badly scored. The segments of the commutator are copper, and were once upon a time separated by mica insulators. These are newer, and don't seem to have the mica. They had a bit of carbon streaking, but weren't scored all that badly. They did quit working, and I was able to find new brushes the old ones appear to be a bit to short to make reliable contact. The whole lift has been sitting for at least 15 years, so might also have some corrosion problems since the shed they were in is not weather proof, nor necessarily water tight. But it worked for several months before the problem appeared.? I've been working on it as needed for fear that it would get disassembled and left in pieces like so many of my other projects have been. It took nearly two years for the Atlas TH42 to get the wiring redone AFTER I had all the parts and wire, and everything apart, since I kept getting distracted by other things. Trying to NOT let that sort of thing happen with this lift, as I need it to keep me from having to lift her 240lb power chair into the car... My back hates me every time I even THINK about doing that again. ;) 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! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Wednesday, September 6, 2023 at 11:27:50 AM CDT, Andrei <calciu1@...> wrote:
Is there a reason for turning the armature (clearly i have no idea about motors?)?
From: [email protected] <[email protected]> on behalf of rfmarchi1 <rfmarchi@...>
Sent: Wednesday, September 6, 2023 12:23 PM To: [email protected] <[email protected]> Subject: Re: [atlas-craftsman IO] Back Gear Pin & Rattle ?
Two hints on this topic. If you use an abrasive cloth like emery of rouge paper, be sure to thoroughly clean the surface when you¡¯re finished. They contain some kind of binder wax that doesn¡¯t get along well with electric current and heat. If you do try to turn the armature be aware that turning copper requires a sharp tool and a negative rake. If the tool is not sharp it will mush the copper. If the rake is not negative (about 5 degrees in my experience) it will dig in. ? Sent from for Windows ? |
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Re: Back Gear Pin & Rattle
I was able to do the work with a mildly abrasive (supposedly diamond) nail care "tool." I knew about how gummy copper is, and that the old machinists used milk as a lubricant when turning parts made of copper, but the commutators weren't that badly scored or damaged. Dodged several bullets there, I think. ;)? I blew the little bit of fluff and particulates I could see of them, and have the motors nearly reassembled, but due to an appointment cancelation, I think I'll pull them back apart and spray the commutators with electrical contact cleaner to wash off anything I may have missed. May run to Metals Supermarkets and see if I can find a stick of brass close to the right size... Just in case the brush caps I ordered don't fit. Though I have a stick of 5/8" Delrin impregnated with Teflon that I could use, and not have to travel or spend more money if I can find it. ;) William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better. Expect in one hand, expectorate in the other. See which one gets full first.
On Wednesday, September 6, 2023 at 11:27:50 AM CDT, Andrei <calciu1@...> wrote:
Is there a reason for turning the armature (clearly i have no idea about motors?)?
From: [email protected] <[email protected]> on behalf of rfmarchi1 <rfmarchi@...>
Sent: Wednesday, September 6, 2023 12:23 PM To: [email protected] <[email protected]> Subject: Re: [atlas-craftsman IO] Back Gear Pin & Rattle ?
Two hints on this topic. If you use an abrasive cloth like emery of rouge paper, be sure to thoroughly clean the surface when you¡¯re finished. They contain some kind of binder wax that doesn¡¯t get along well with electric current and heat. If you do try to turn the armature be aware that turning copper requires a sharp tool and a negative rake. If the tool is not sharp it will mush the copper. If the rake is not negative (about 5 degrees in my experience) it will dig in. ? Sent from for Windows ? |
Bill in OKC too