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Re: [PSUBS-MAILIST] Interesting item on eBay web siteitem#275822570: X-9 "Y...
----- Original Message -----
From: <Subscuba@aol.com>
To: <personal_submersibles@psubs.org>
Sent: Tuesday, March 07, 2000 1:28 AM
Subject: Re: [PSUBS-MAILIST] Interesting item on eBay web
siteitem#275822570: X-9 "Y...
"Hello Pat,
The motor controller is single ended not a H or full bridge as I suspect
Minn Kota has and thus my design may be more efficient."
Hmmm. Ya got me thinking now. I'm using the stock MK variable thrust.
forward & reverse controller. Wonder if I could get more power by building
a custom potentiometer? Also, my Minn Kota 4HP runs at 24 VDC off two
twelves in series; wonder if the lower end would survive 36 volts (an extra
12 cut into the system for short term "burst of power" operation).
>
>" QUESTION: Can you tell me the voltage and current ratings of the
"Monster"?"
She's 36 volt direct current from three / twelves wired in series; but I
don't have any other specs off the top of my head; and I can't go to MK's
site right now. But if you go to their website, they've got a lot of info ,
including the specs for (I seem to recall) three (?) variants of the 101#
thrust unit.
>" Do you have to limit initial current surge to prevent stator
demagnetization?"
I'm not sure if demagnetization is the problem / reason, but I believe
that's how the stock MK controller is designed to work. Kind of "eases" the
juice to the motor to keep her from balking under load.
"I assume the motor is effectively shunt wound with a permanent magnet
stator."
I think they (MK) all are, aren't they? It's been a while since I opened it
up, but as I recall it's permanent magnets mounted inside the case; the
armature rotates in the field; and there's two fat spring-loaded brushes
(that the MK techs say will work even with the case flooded, though the
brushes will wear out a LOT faster).
>
" I presently have three 12 volt batteries and can drive a 36 volt motor but
I doubt if the speed increase would be worth the decreased battery run time.
Still it would be interesting."
(I'd like a little extra speed at times, myself. For some reason,
spectators expect to see the NAUTILUS running at high speed with decks
awash. (heh!) I've thought about everything including a jetski
squirt-drive; but that's a big modification, and I'd have to do surgery on
my hull. Just don't want to do that to this boat. More E-motor would be
nice, though.)
Are you talking about rigging your present 24 VDC motor to accept another 12
volts? This is what I was wondering about above (and frankly, I'm also
wondering if this and a little tweaking isn't how MK came up with the 101
Monster. If the motor can handle the juice, it seems maybe they could
reduce overheating to acceptable levels by swinging a tamer prop. That and
some resistance changes to the controler, and there you go: 36 Volt, 101#
Monster. (I don't know this for sure, but I sure am wondering.)
Think I could put 36 volts through my 24 VDC 4HP without overheating the
lower end (too much) or frying the controller?
The lower end windings and brushes look pretty heavy duty. If I buy the
Monster (and I'm planning on it), I may experiment with this. Whatayathink?
Will I melt it or not?
" Ken Martindale
>
> PS Don't forget I have a wet sub."
A nice one, too! Send me some pix! ;-)
Pat