Alec, How do you compensate the oil? I'd love to try some of those 36 volt
Minn-Kotas. They've got a ton of umph, and might get me back a couple of
hundred pounds of payload from George's Model-T Rex style thruster cans. And it
would be cheap, too. Vance
I had an email conversation with Carl about a year ago on that
topic. They're just straight air compensated, with Swagelok SS fittings tapped
into the trolling motor casings. The reason I'd contacted him was to ask whether
he was using air, because some on here maintained that at his depths, the
partial pressure of O2 in air would be a fire hazard. I think his sub
demonstrates it's not.
BTW Snoopy's trolling motors started out air compensated and are
now in their second season with oil compensation. I have nothing at all against
air compensation, and would go with that if my air bottles were outside the
hull. But the way it was implemented on Snoopy the air was passed through the
shafts from the cabin, and there just wasn't space to do it properly along with
the cables. What's been interesting about the switch to oil is I can't notice
ANY difference. The motors seem to pull just as strong, and even sound exactly
the same as before.
cheers,
Alec
Oil compensated DC motors work just fine at moderate depths. Alvin had
problems originally with brushes arcing, but he Hymak 5 hp motor used
by Hyco on nearly everything they built was a serious workhorse. You get to tear
it down and change brushes periodically as they wear faster, and they'll
get the oil dirty, so you'll have to watch that. I was on Karl Stanley's web
page last night and it looks to me like his Idabel is using about a case of
trolling motors, and they must be compensated, as the sub is rated for 3000 foot
service. Maybe we ought to ask him what the secret is, if any.
Vance
-----Original Message-----
From:
DJACKSON99@aol.com
To: personal_submersibles@psubs.org
Sent: Wed, 15 Nov
2006 10:35 PM
Subject: [PSUBS-MAILIST] Oil Compensated Thursters
Can anyone support this statement: "Scripps has tried to fill the DC
motors with oil, but the oil gets between the brushes and the commutator, where
the insulation properties of the oil causes problems. Although it would be
possible to use high voltage to break through the oil film, the high voltage is
a safety hazard for the divers."
I was thinking about 24 or 36 volt oil compensated brushed trolling motors,
but after reading the above I looked and could not find any examples of oil
compensated brushed motors under 100 volts.
What are your experiences and thoughts?
Thanks
--Doug J
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