----- Original Message -----
Sent: Thursday, January 19, 2006 7:47
AM
Subject: Re: [PSUBS-MAILIST] motor
pressure comp
with pressure
compensation of the housing. this can be done with an active system i.e. using
high pressure air
Hi, Rick M - you mean low pressure don't
you? 20 atmospheres (660 ft) is still only 294 lb of
compensation.
Rick L
----- Original Message -----
Sent: Wednesday, January 18, 2006 4:10
PM
Subject: [PSUBS-MAILIST] motor pressure
comp
GUYS:
I have heard a lot of
discussion over thruster motor and sealing requirements. I see the easiest
way to stop the flooding problem is with pressure compensation of the
housing. this can be done with an active system i.e. using high pressure air
or a passive system using oil and a balance piston. the only problem with
oil is that you get about a 20% reduction in power due to the resistance of
the oil on the rotor. This can be minimized by filling the voids in the
rotor with low density epoxy.
you should use dielectric
transformer oil for this purpose, it can be had from any high voltage
transformer repair shop or good pump motor repair shops. see attached
drawing for a simple layout, it is in my pictures of my frappr. I have
test tanked a minnkota to 2000 psi or 4000 ft with this setup. The key is to
make sure that the piston is balanced
rick m
http://www.frappr.com/?a=myfrappr&id=386116