[Milsurplus] Dynamotor brushes

[Charlie L.]

One thing about using dynamotors with your milsurp, they last a very long
time on the ground, compared to  operating at up to 30K feet in
unpressurised planes where  they arced like the dickens up there.  A
contact I have who restores electrically operated turrets for WWII AC like
the B17, said he has never replaced the brushes in the amplidynes that
power those turret motors.  That also brings up a question as to  their
composition.  I wonder if those brushes intended for high altitude, had a
different make up than those used in motors that stayed at sea level?
Maybe a harder carbon formula to last over several missions  from England
to Germany and back?  Is there any data on how long the brushes did last in
the ETO and how often they were changed?  Perhaps they left the radio gear
off most of the time, but the intercom system had a dynamotor powered
amplifier, BC347,  that had to be running all the time.

Charie, W4MEC in NC
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