Re: [PSUBS-MAILIST] Pressure compensation

[Subscuba@aol.com]

In a message dated 8/12/00 2:00:37 PM Eastern Daylight Time, 
dblake@bright.net writes:

<< 
 Use of an oil that is typically used in refrigeration compressors--or in my
 mind submersible pumps--would have to remain O2 free to prevent corruption
 of the extremely delicate magnet wire sheath.  O2 mixed with the oil creates
 an acid that attacks the windings.
  >>

I wasn't referring to the O2 problem but the decomposition and contamination 
of the brushes in a trolling motor. The contact between the brushes and the 
commutator would be the problem no matter what kind of oil. Normal running 
produces a limited amount of arcing across the brush contacts. When this path 
is contaminated with oil brush life may be reduced to a few minutes. Use of a 
non reactive gas would be better but then no pressure compensation. I suspect 
the motors that are filled with oil don't have brushes such as found in 
trolling motors. Refrigeration compressor motors and submersible pump motors 
do not have brushes and are free of this problem.

Despite all this theory, has anybody tried oil in a trolling motor with 
brushes??

Didn't mean to step on your toes about the 120 volt problem, I just wanted 
not to mislead. My 36 volt system is ungrounded.

Have fun,

Ken Martindale