Electric mower repair advice?

[Jdmst]

If anyone could provide some advice I would appreciate it very much.

I was given a Black and Decker electric mower. Model LM100 or possibly LM106, hard to tell. When I try to run it it trips the breaker every time. I took the cover off and checked the brushes. They are about 5/8th of an inch long. When trying it with the cover off there is a lot of sparking between each of the brushes and the armature? before it trips the breaker. It sure looks like too much sparking to me, almost like a dying out child?s sparkler. It will run for 2 or 3 seconds before the breaker trips.

Any thought as to how I can repair it? Or any sites that I can be pointed to that will help?

Thanks again, John

[Warren Weber]

John.. Most likely a shorted armature. Check B & D web site and see if you can determine cost of part. May not be worth repairing. All the B & D stuff I have purchased had a short life, so I no longer buy there products.. Warren

[Jdmst]

Hi Warren, Thanks for the info. It sounds right to me. There was nothing wrong in my opinion with the brushes. I will just toss the thing out I think. Thanks again.

John

[Michael Baugh]

Black and Decker have really sank low over the last few years.

[Banister Stairwell]

Hi John,

Before you throw it out, check and see if you can take the motor itself in somewhere and have it repaired. I'm talking about an outfit who's only business is that of repairing electric motors. These places have all the parts and tools necessary to rewind armatures, turn and true commutators, fabricate new brush assemblies, replace motor bearings...the whole nine yards. I've been able to resurrect a number of devices that use electric motors that otherwise were candidates for the scrap heap by removing the defective motor and simply taking the motor in to have it repaired.

I would at least look into this before throwing the mower away.

Just my .02 cents.

[Warren Weber]

motor armatures were soaked in a special varnish. Then baked. This anchored the windings so vibration would not allow the windings to rub and then short to another wire. The cheap junk made now are just wound no varnish. Some do not even have the wires anchored well at the termination to bars (where brushes ride) so a lot of failures are due to a broken connection to the bar. This will cause heavy arcing on the brushes. Warren

[Bill Schnakenberg]

No disrespect, but you are a couple of decades older than I (DOB 1937), and they don't use varnish anymore, they use epoxy to hold the windings together.

[Warren Weber]

commutators,

[Michael C De Vito]

Hello Hiview, Try removeingThe brushes & cleaning the armature with steel wool or fine sandpaper, brushes leave residue. Mike D.

[Jdmst]

SNIPPED...

Mike D suggested that I clean the armature. I'll give it a shot, thanks Mike. But, I think Warren has got it right. There is one hell of a lot of arcing at the brushes. Anyway, it was free so it can serve as an education for me as I know so little about how electricity works.

Thanks for the thoughts everyone.

John

[John Normile]

Many modern motors use bondable wire. An adhesive resin is applied to the magnet wire at the manufacturer. After winding the wires are heated and the wires are bonded to each other. This eliminates the need to apply a varnish, epoxy, resin, etc., and also eliminates the cure cycle for these materials.

John Normile