[Milsurplus] RE: [ARC5] PE-73 Armature needed

[Richard Brunner]

Re
....  It should be easy to find the winding segment with the short.  A 
low-reading ohmeter like a Fluke 77 is ur friend here.
> That's the funny part; ALL the segments show a short to ground!!!
> I did a sanity check on mine and they all show infinity. When it went it 
> ....

Yes.  There is dc continuity between all commutator segments, so you only 
can determine that there is a ground, but not where.  Since the windings 
overlap, a total rewind may be necessary.  It doesn't look too hard if you 
want to get into it.
(Richard, AA1P)

Consider:  Shorted armature winding
You can check the armature for shorts while the motor is uncoupled. After 
removing all brushes from the commutator, apply rated voltage to the shunt 
field and rotate the armature by hand. One or more shorted coils is 
indicated if the armature seems to be "bound up" or cogs as you rotate it.

If the motor will run for a short while before the overload trips or the 
fuse blows, shut down the motor and then feel the armature coils with your 
hand. Shorted coils will feel hotter than the others because they will have 
had heavy circulating currents induced into the shorted turns.

Defective field winding.

A DC motor must have 100% field strength to produce its maximum torque and 
to keep the armature amperage within proper limits. Reduced field strength 
will cause high armature currents.