Re: thank you ken

[Subscuba <Subscuba@aol.com>]

Shayne,

I use pressure compensation with a Scuba regulator so I don't need any
modification of the seals. Also by placing the regulator at the lowest point
in the Sub I have a slight positive pressure in the air spaces in my Sub,
assuming the regulator stays at the lowest point.

I think Minkota motors have enough room along the shaft to possibly install
two seals although I have not tried it. Be aware that if you don't use some
sort of active current limit in series with the motor a locked shaft will draw
enough current to demagnetize the permanent magnets and effectively ruin the
motor. The controllers offered by Minnkota have this feature  as well as my
design and use the same switching frequency as my motor controller at 20 Khz.
I'm not sure if all their motors have this problem but the one I am using
does. It's a 70 pound thrust 24 volt motor. I didn't want to use their
controller since it was $169 and mine cost me about $50 and I can fix or
change it as I wish (as well as interface to a computer).

Good Luck with your ROVs, if I can help any futher I will. Don't forget about
the other vendors. Surf or crawl the Web for their Websites. I just got
Minnkota's latest brochure which I ordered over their Website and they are now
listing a 96 pound thrust motor that only draws 56 ampere from 24 volts. It's
listed on page 25 of their brochure.

Ken Martindale