[PSUBS-MAILIST] Brushless Thrusters
Vance Bradley via Personal_Submersibles
personal_submersibles at psubs.org
Sun Sep 7 19:21:33 EDT 2014
Low rpm was the key. Much faster and the rubber overheats.
Vance
Sent from my iPhone
> On Sep 7, 2014, at 7:04 PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> Vance,
> Sounds like a good option if you have in house machining. The cartridge seal shaft is equally fussy, it took me a few try's to get it perfect. I am sure Brian is a better machinist than I am, so should be no problem.
> I believe the slower the rpm the better with o-ring seals.
> Hank
> --------------------------------------------
> On Sun, 9/7/14, via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters
> To: personal_submersibles at psubs.org
> Received: Sunday, September 7, 2014, 6:49 PM
>
> Hank,
>
>
>
>
> Harbor Branch used o-rings on the reduced output 1
> 1/4 thrusters on the JSLs. The mid-body on the hard can
> (actually the back 25% or so of the cylinder section) was
> machined on the output side for planetary gears, and
> machined on the motor side to replace the entire output
> plate/bearing case for the motor itself (like a golf cart
> motor bolts into a differential). Pretty nice and compact
> for the day.
>
>
>
>
>
> The rear section of the hard can behind the gear
> case is a hollow sand casting shaped like the long end of an
> egg, webbed internally to support a 1" shaft, double
> bearings, with double thrust bearings, and a tapered,
> polished, hardened aluminum sleeve pressed in from the
> pressure side.
>
>
>
>
>
> The shaft itself was machined to carry double
> o-rings in square cross section grooves and terminated on
> the internal end with a flex-coupling which mated
> (obviously) to the output of the planetary output. A big
> shaft was necessary to keep the jitters down to more or less
> zero. Everything needs to stay exactly centered, as the
> O-rings will go to pot a whole lot faster if there is any
> flex or vibration at all in that prop shaft
> shaft.
>
>
>
>
>
> Lots of development to get it right, finally, but
> the props turned about 275-300 rpm (I don't remember
> exactly, but something like that). 14" X 14" Kort
> style prop in a machined syntactic foam nozzle supported on
> a 4-legged frame welded to the aft part of the shell. I
> actually have a blueprint of it, somewhere around here. For
> those interested, the tip clearance between blade end and
> nozzle sleeve was about 50-thousandths. NOTE: That would be
> of an inch, Emile.
>
>
>
>
>
> There were no speed controls on the boats.
> Fwd-Off-Rev only. You just turned thrusters on or off to
> vary the push. When I was there, we had 5 for forward and
> reverse (3 in a row on the centerline with 1 each to port
> and starboard aft) plus a vertical and horizontal pair
> forward and aft for steering and fine maneuvering (fine
> maneuvering my ass!!!). That's right. NINE thrusters
> that probably with cabling weighed over half a ton. Plus two
> or three spares in the kit ready to bolt up at a
> moment's notice as replacements. We were definitely in
> the motor business with those babies.
>
>
>
>
>
> They were home grown but worked reasonably well,
> although they were a little noisy with the gear case and
> whatnot. That said, I never saw the electrical side flooded
> on one of those things. Not once. Ever. We had a routine
> service schedule and changed a thruster every so many hours
> of service. Just put a fresh one on (two people could do a
> change-out in about three minutes), then tear the
> to-be-serviced unit down to check brushes and bearing lube
> and change the shaft o-rings (which would be looking a
> little fuzzy by then, but still worked fine--and even if
> they looked brand new, we changed them). It needs a really,
> really first rate waterproof lubricant, as the internal
> shaft o-ring runs hotter than the one in contact with the
> water, and was often in worse shape than the one primary as
> a result.
>
>
>
>
>
> Once the JSLs re-certified to 3000 feet,
> engineering redesigned the seals for better service, using a
> ceramic cartridge seal in place of the o-rings, but that was
> after my day. I'd hate to even think what
> one would cost today, built commercially. You wouldn't
> use them, probably, as a unit with twice that power is
> probably a third the size and weight.
>
>
>
>
>
> Those thrusters on the Tritons,
> for instance, look positively tiny by comparison, and
> they're rated at over 2 hp. Then there's our own
> Uncle Dr. Phil's new mag coupled ones. Now there's a
> Christmas present to ask Santa for.
>
>
>
>
>
> All that aside, the o-rings will
> work if you plan regular service (ie, scheduled o-ring
> replacement) and don't wait for water intrusion. They
> have to be done right during construction, though. Those
> surfaces have to be mirror smooth.
>
>
>
>
>
> Vance
>
>
>
>
>
>
> -----Original
> Message-----
>
> From: hank pronk via Personal_Submersibles
> <personal_submersibles at psubs.org>
>
> To: Personal Submersibles General Discussion
> <personal_submersibles at psubs.org>
>
> Sent: Sun, Sep 7, 2014 4:51 pm
>
> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters
>
>
>
>
>
>
>
>
>
>
> Brian,
> Vance would know better than me, but I think if you keep the
> rpm under 1,000 you
> can use an o ring for a seal. I thought Perry did that in
> the early subs to
> 1,000 feet.
> Hank--------------------------------------------
> On Sun, 9/7/14, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
>
> wrote:
>
> Subject: Re: [PSUBS-MAILIST] Brushless Thrusters
> To: "Personal Submersibles General Discussion"
> <personal_submersibles at psubs.org>
> Received: Sunday, September 7, 2014, 4:42 PM
>
>
> Brian,
> You can use a simple
> mechanical seal, that is what the K subs have. An 891
> Chesterton mechanical seal is good fo 600 psi, that is what
> Gamma had when I got it. You can buy them on ebay for 100
> bucks. Build the shaft to fit the seal, and your
> sailing.
> Hank--------------------------------------------
> On Sun, 9/7/14, Brian Cox via
> Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
>
> Subject: Re:
> [PSUBS-MAILIST] Brushless Thrusters
> To:
> "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>
> Received: Sunday, September 7, 2014, 4:29
> PM
>
> I
>
> talked to a hydraulics guy a few days ago about making a
> seal for my motor pod. I told him I had a
> high pressure
> tank that I wanted to turn a
> shaft inside the tank to stir
> the contents
> at 250 psi, ( didn't want his eyes to
>
> glaze over if I mentioned submarine !) Anyway he
> directed
> me to a system using a bronze
> fitting that would tighten
> down these rings
> he called "cheverons" they are
>
> mating rings of a very high durometer . the bronze is
> for
> mating with stainless . I would have
> to machine an
> assembly for this , but once
> I have my shaft size (1 inch
> most likely) I
> will be able to size everything
>
> accordingly. Brian
>
>
> ---
> personal_submersibles at psubs.org
> wrote:
>
> From: hank pronk
> via Personal_Submersibles
> <personal_submersibles at psubs.org>
> To:
> personal_submersibles at psubs.org
> Subject: Re:
> [PSUBS-MAILIST]
> Brushless Thrusters
> Date:
>
> Sun, 7 Sep 2014 07:07:20 -0700
>
> Alan
> When I upgraded the
> cartridge seal in Gamma, I needed a pretty
> Beafy thrust
> bearing, it was no problem to
> get. have since changer to
>
> Magnetic. I think you could replace the bushing
> in a
> thruster with a ball bearing and never
> look back.
> Hank
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> From:
>
>
>
> Alan via Personal_Submersibles
> <personal_submersibles at psubs.org>;
>
>
>
>
>
>
> To:
>
>
>
> Personal Submersibles General
>
> Discussion <personal_submersibles at psubs.org>;
>
>
>
>
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>
>
>
>
> Subject:
>
>
>
> Re: [PSUBS-MAILIST] Brushless
> Thrusters
>
>
>
>
>
> Sent:
>
>
>
> Sun, Sep 7, 2014 1:43:49 PM
>
>
>
>
>
>
>
>
>
>
> Hi Hank,the kort
>
> nozzle on the Indonesian thruster looks a bit
> Naff. ( I am designing an art work
> here.)I could get a price for the unit
> without
> kort nozzle, butI'm wondering
> if I could
> build something for 1/2 that
> price.There are some
> reasonably priced
> brushless motors about.I
> don't know
> that I could just retro fit a thrust bearing
> inside the can of the motor.I tried to put
> a
> thrust bearing for reverse inside my
> brushed thrusters,
> butcouldn't find one
> with a thin enough
> section to fit.Also the
> motors are a bit
> expensive to just buy
> & hope you can fit
> one.How did you fit
> the thrust bearing on Gamma?
> Did the
> propellor shaft extend out the backof
> the
> motor?Alan
>
> Sent from my
> iPad
> On 7/09/2014, at 7:22 pm, hank pronk
> via
> Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
>
>
> Allan
> Dont
> worry about
> thrust bearings to much. They are aesy to get,
> I bought one for Gamma , real heavy duty for
> 80 dollars.
> Personally I would just use a
> good quality bearing and
> replace it once a
> year for 8 bucks, if it is a small
>
> thruster. Are you not happy with the
> Indonesia thrusters?
> Or to pricey?
> Hank
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> From:
>
>
>
> Alan via
> Personal_Submersibles
> <personal_submersibles at psubs.org>;
>
>
>
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> To:
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> General
> Discussion <personal_submersibles at psubs.org>;
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> Subject:
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>
>
> [PSUBS-MAILIST] Brushless
> Thrusters
>
>
>
>
>
> Sent:
>
>
>
> Sun, Sep 7, 2014 11:58:56 AM
>
>
>
>
>
>
>
>
> Hi people,
> I've
> spent several hours today looking at brushless
> thrusters
> & wonder if anyone else has
> looked at them or got any
> ideas. There is
> the Indonesian thruster I posted a few weeks
> back at US 2,200. There is also the Haswing
> Protruar 2hp
> that Emile has; however they
> state that it's for fresh
> water only,
> & I think Emile said it was a bit noisy.
> The inrunner motors that have the winding
> on
> the outside, seem a good option as they
> cool through
> convection to the can. They
> also need higher revs for torque
> &
> require a planetary gear box or similar. ( which a lot
> have built in)
> I was
> looking at the
> option of making my own
> thruster, however the motor would
> require a
> thrust bearing & I don't
> know of
> any that would have one other than
> maybe
> a high powered battery operated drill.
> Any
> thoughts, suggestions thanks.
> Alan
>
> Sent from
>
> my
> iPad
>
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