Lewmar Windlass Motor

[DayDreamer41]

Last fall I removed my thruster motor and took it to a rebuild shop, they tested, undercut the commutator and put the new brushes in that I provided, as promised the motor turned out as good as new!! I looked for an automotive rebuild shop, starters and alternators, read the reviews on the places where reviews were available and vowla like new thruster......yeh!

 

[JimInPB]

When installing new brushes, it is best practice to bed them in. This basically means that you get a piece of com stone, rub it on the commutator while the motor is running, then watch the flat front edges of the brushes get worn away to match the shape of the commutator. As soon as they match, blow out ALL the com stone fragments. If some fragments are left behind, then brush life will be shortened. If you forget to blow them out at all, the brushes can disappear in less than an hour of run time.

Plymouth isn't the worst place to be stuck. At least you can get some good seafood down on the town wharf.

 

[DayDreamer41]

@JimInPB , that would be one way to do it, but a motor shop actually undercuts the insulation between the commutator segments, what happens if this is not done correctly the brushes hop off the segments at each insulation break, causing arcing reducing the effectiveness of the power transfer and significantly reducing brush life.

 

[jviss]

I am stuck in Plymouth, MA.

Not a bad place to be stuck. My daughter lives there, overlooking Warren Cove.
Try KKatie's Burger Bar - I love that place. Lots of other good options, too.
http://www.kkaties.com/

 

[JimInPB]

@JimInPB , that would be one way to do it, but a motor shop actually undercuts the insulation between the commutator segments, what happens if this is not done correctly the brushes hop off the segments at each insulation break, causing arcing reducing the effectiveness of the power transfer and significantly reducing brush life.

I was only commenting on installing new brushes, in a motor that does not need other work. What you describe is what old timers sometimes refer to as "high mica", an old industry buzz word from back in the days when mica was used as the insulator material. In my experience, it is uncommon to need to relieve the insulator segments unless the commutator has been turned down, which is something that is usually done to eliminate pitting.

 

[jviss]

I was only commenting on installing new brushes, in a motor that does not need other work. What you describe is what guys, in the shop that I worked at back in the 1980's, referred to as "high mica" from back in the days when mica was used as the insulator material. In my experience, it is uncommon to need to relieve the insulator segments unless the commutator has been turned down, which is usually done to eliminate pitting.

I've rebuilt motors, including cutting commutators on the lathe. Sometimes you need to cut back the mica even when you don't take a cut on the commutator, just from wear. That said, as long as you have the motor apart, take a light cut and cut back the mica - can't hurt!

 

[DayDreamer41]

In my case I didn't see the state of commutator as I did not open the motor up, but I am sure given the way the motor was performing that there was significant evidence of arcing ergo the need to turn down the commutator, the motor rebuild shop did a wonderful job of bringing the motor back to its full effectiveness, my intended point was to bring to light that there is no sense throwing out the baby with the bath water, when all it needs is some professional service.