Now it works, but I don't know why

Late last spring, the South Coast Air Quality Board had an offer: bring in your working gasoline-powered lawn mower (and $99) and they'd give you a brand new Black & Decker battery powered electric mower. Since my old Briggs & Stratton mower was on it's last legs, I decided to take them up on the offer even though I had some doubts about how well an electric mower would work. Pretty well, as it turned out. The 38 VDC mower had no problem with mowing both front and back yards on a single charge. That is, until it's first encounter with this spring's weed crop.

My back yard is not landscaped. There is no real lawn and every spring the weeds and wild grasses go wild, often reaching over two feet (0.6m) high. That's more than any electric mower could reasonably be expected to handle. Of course, when it comes to things like this, I am not a reasonable man, always sure that I can coax high performance out of pretty much any machine with my superior operating skills.

You can guess what happened. Yep, the mower stopped working midway through the job. I feared the worse—a burned out motor—but upon disassembly, I could find nothing wrong. The battery was fully charged, all the switches appeared to work and the motor appeared to be fine. I even pulled the brushes to see if they were okay.They were, it just didn't work. Discouraged, I put the whole thing back together and, for no particular reason, tried turning it on one last time. Damned if the thing didn't work perfectly!

This is not the first time something like this is happened—take some broken device apart, look at it, shrug, put it back together and it's working again—and it always leaves me wondering what the problem was.

Maybe the motor got too hot and a thermal cutoff switch opened and it took a while for it to reset. Electrics are nice but I prefer gas.

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Originally Posted by n2ize

Maybe the motor got too hot and a thermal cutoff switch opened and it took a while for it to reset. Electrics are nice but I prefer gas.

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That's what I thought but there was no thermal cutoff on the unit that I could find and, besides, the problem actually occurred a couple of days ago. I just didn't get around to looking at it until today and it didn't run when I tested it before beginning my repair efforts.

Yeah, the thermal OL would be my guess, too. Next time it happens, pack it in dry ice, it should come right back.

Either that or a brush lost contact, possible commutator burn from arcing, so when you replaced them you restored contact. I've had that happen a couple of times.

"Of course, when it comes to things like this, I am not a reasonable man, always sure that I can coax high performance out of pretty much any machine with my superior operating skills."

Sounds like a Tim Taylor quote!

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Originally Posted by KJ6BSO

That's what I thought but there was no thermal cutoff on the unit that I could find and, besides, the problem actually occurred a couple of days ago. I just didn't get around to looking at it until today and it didn't run when I tested it before beginning my repair efforts.

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I've had some battery operated stuff that had a thermal OL on the motor of the tool, as well as one in the battery pack. The only people making money are the TOL manufacturers.

Whinney bitch

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Originally Posted by kb2vxa

Either that or a brush lost contact, possible commutator burn from arcing, so when you replaced them you restored contact. I've had that happen a couple of times.

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That's the best guess I can come up with as well.

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"Of course, when it comes to things like this, I am not a reasonable man, always sure that I can coax high performance out of pretty much any machine with my superior operating skills."

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Sounds like a Tim Taylor quote!

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We have some things in common. I repowered the garbage disposal with a Harley motor.

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Originally Posted by NA4BH

Whinney bitch

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^^^^^ + 10,000 Maxwells

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Originally Posted by KJ6BSO

Late last spring, the South Coast Air Quality Board had an offer: bring in your working gasoline-powered lawn mower (and $99) and they'd give you a brand new Black & Decker battery powered electric mower. Since my old Briggs & Stratton mower was on it's last legs, I decided to take them up on the offer even though I had some doubts about how well an electric mower would work. Pretty well, as it turned out. The 38 VDC mower had no problem with mowing both front and back yards on a single charge. That is, until it's first encounter with this spring's weed crop.

My back yard is not landscaped. There is no real lawn and every spring the weeds and wild grasses go wild, often reaching over two feet (0.6m) high. That's more than any electric mower could reasonably be expected to handle. Of course, when it comes to things like this, I am not a reasonable man, always sure that I can coax high performance out of pretty much any machine with my superior operating skills.

You can guess what happened. Yep, the mower stopped working midway through the job. I feared the worse—a burned out motor—but upon disassembly, I could find nothing wrong. The battery was fully charged, all the switches appeared to work and the motor appeared to be fine. I even pulled the brushes to see if they were okay.They were, it just didn't work. Discouraged, I put the whole thing back together and, for no particular reason, tried turning it on one last time. Damned if the thing didn't work perfectly!

This is not the first time something like this is happened—take some broken device apart, look at it, shrug, put it back together and it's working again—and it always leaves me wondering what the problem was.

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Is it possible it's devine intervention funneled through the charisma of Pope Carlo ?????

.....nyaaaah ..... I vote the thermal overload cutoff re-setting itself as well ...... :mrgreen: