Check out this commutator (brushed pm dc winch motor)

[electromateria]

I bought a crusty winch for $20 and tore it down and cleaned / restored it.

I found the commutator kind of cool because I've never seen one like it.

Is there any advantage to this placement compared to a more conventional one?

[David Hess]

Is there any advantage to this placement compared to a more conventional one?

The brushes are on the end instead of sides which may be more convenient.

[Doctorandus_P]

I've seen this arrangement in starter motors for cars. The main advantage is probably ease of assembly. If you've ever taken apart the back flange of a small DC motor and tried to put it back together you probably know how finicky it can be to push both brushes outwards while trying to push them over the commutator.

From an electrical point of view it probably is a bad thing. It decreases timing accuracy of the commutation and the big difference in surface speed over the brushes causes uneven wear.

[David Hess]

The AC motors in O-gauge Lionel trains use this configuration.  I assume that a narrower but longer motor is a better form factor to put inside of a model train engine.

[TomKatt]

Looking closely, the commutator seems to have brushes on both axis - both the face and also the circumference?

Edit - N/M I see that is simply the binding posts for the braided brush leads...

[Gyro]

I've seen this arrangement in starter motors for cars. The main advantage is probably ease of assembly. If you've ever taken apart the back flange of a small DC motor and tried to put it back together you probably know how finicky it can be to push both brushes outwards while trying to push them over the commutator.

Even more finicky on a starter motor, there are four brushes to wrangle simultanously.


P.S. It's surprising how little of the winding space is being used in the rotor, normally the passages are packed. Presumably they're getting away with finer gauge wire for intermittent use - maybe they've actually used de-rated starter motor hardware.