[PSUBS-MAILIST] Dive report: Snoopy at Seneca
Ken Martindale via Personal_Submersibles
personal_submersibles at psubs.org
Sun Jun 7 20:29:52 EDT 2015
Sine wave converters have “soft switching” and don’t have the high switching currents a “hard switching” converter so they are better in this respect.
Thanks for the tip on the tuned inductors.
Ken Martindale
From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan James via Personal_Submersibles
Sent: Sunday, June 07, 2015 4:23 PM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca
Thanks Ken,
Keith T mentioned the tuned inductor.
<http://en.wikipedia.org/wiki/LC_circuit> http://en.wikipedia.org/wiki/LC_circuit
I am not familiar with it.
In the article I posted it mentioned these sine current controllers.
<http://www.sinusleistungssteller.de/en_SinusStromRegelung.html> http://www.sinusleistungssteller.de/en_SinusStromRegelung.html
These have been tested to 70 meters without capacitors, but very expensive.
Alan
_____
From: Ken Martindale via Personal_Submersibles < <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
To: 'Personal Submersibles General Discussion' < <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
Sent: Monday, June 8, 2015 3:14 AM
Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca
What's a tuned inductor?
Ken Martindale
-----Original Message-----
From: Personal_Submersibles [mailto: <mailto:personal_submersibles-bounces at psubs.org> personal_submersibles-bounces at psubs.org] On Behalf Of via Personal_Submersibles
Sent: Saturday, June 06, 2015 9:33 PM
To: Personal Submersibles General Discussion
Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca
Also tuned inductors will help disipate the spikes caused by the controlers.
Keith T
Alan James via Personal_Submersibles < <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org> wrote:
>Thanks Ken,I was nearly going to ask you to comment in my post.Is there
>an alternative to capacitors or to the electrolitic capacitors usually
>used?I was looking at this
>option.http://www.dialelectrolux.ru/files/file/electronicon/e61-data-ch
>arts-engl-deut.pdf
>Alan
> From: Ken Martindale via Personal_Submersibles
>< <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
> To: 'Personal Submersibles General Discussion'
>< <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
> Sent: Sunday, June 7, 2015 12:19 PM
> Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca
>
>#yiv9053454032 #yiv9053454032 -- _filtered #yiv9053454032
>{font-family:Helvetica;panose-1:2 11 6 4 2 2 2 2 2 4;} _filtered #yiv9053454032 {panose-1:2 4 5 3 5 4 6 3 2 4;} _filtered #yiv9053454032 {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;} _filtered #yiv9053454032 {font-family:Georgia;panose-1:2 4 5 2 5 4 5 2 3 3;}#yiv9053454032 #yiv9053454032 p.yiv9053454032MsoNormal, #yiv9053454032 li.yiv9053454032MsoNormal, #yiv9053454032 div.yiv9053454032MsoNormal {margin:0in;margin-bottom:.0001pt;font-size:12.0pt;}#yiv9053454032 a:link, #yiv9053454032 span.yiv9053454032MsoHyperlink {color:blue;text-decoration:underline;}#yiv9053454032 a:visited, #yiv9053454032 span.yiv9053454032MsoHyperlinkFollowed {color:purple;text-decoration:underline;}#yiv9053454032 span.yiv9053454032link-enhancr-element {}#yiv9053454032 span.yiv9053454032link-enhancr-view-on-domain {}#yiv9053454032 span.yiv9053454032EmailStyle19 {color:#1F497D;}#yiv9053454032 .yiv9053454032MsoChpDefault {font-size:10.0pt;} _filtered #yiv9053454032 {margin:1.0in 1.0in 1.0in 1.0in;!
}#yiv9053454032 div.yiv9053454032WordSection1 {}#yiv9053454032 Adding extra capacitors helps reduce the magnitude of the inductive voltage spikes. Ken Martindale.
>
>From: Personal_Submersibles
>[mailto: <mailto:personal_submersibles-bounces at psubs.org> personal_submersibles-bounces at psubs.org] On Behalf Of Alan
>James via Personal_Submersibles
>Sent: Saturday, June 06, 2015 6:48 PM
>To: Personal Submersibles General Discussion
>Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca Thanks for
>the report Alec, great stuff.re the motor controllers; I've been
>reading a bit about inductance in long wire runs from battery tomotor
>controllers, that harms the capacitors on the controllers.This could be
>a problem that is unique to our submarines & not an issue with things
>like golf carts& wheel chairs.My reading has been mainly about BLDC
>motor controllers but asume PWM controllers for brushedmotors would be
>similar. Because of the rapid switching on & off of the power to the
>motor, there is acurrent surge hitting the capacitors & the longer the
>wire run, the more the power in the surge.A water analogy would be
>turning a valve off suddenly as washing machines do, sometimes witha
>"thunk" sound & a rattle of the pipes.Hugh mentioned he had problems
>with his Curtis BLDC motor controllers.Attached is the problem &
>solution, which is to put capacitors in parrallel along the battery
>wire; however there must be a better way.Regards Alantoo long battery
>wires will kill ESC over time: precautions, solutions & workarounds -
>RC Groups
>| |
>| | | | | | | |
>| too long battery wires will kill ESC over time: precauti...Careful!
>| too long battery wires will kill ESC over time: precautions,
>| solutions & workarounds Electric Plane Talk | | View on
>| <http://www.rcgroups.com> www.rcgroups.com | Preview by Yahoo | |
>| |
>| | | | | | | | |
>
> From: hank pronk via Personal_Submersibles
>< <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
>To: Personal Submersibles General Discussion
>< <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
>Sent: Sunday, June 7, 2015 12:20 AM
>Subject: Re: [PSUBS-MAILIST] Dive report: Snoopy at Seneca Alec, I
>don't know what type of speed controller you are using, but I like and use Curtis golf cart controllers. They are rated for huge amperage and seem bullet proof. I have an extra 36V controller I can send you to try out. They use a 10 OHM potentiometer for the throttle. They also have a battery protection mode, a sort of get home conservation mode.
>I labeled the motor in Gamma for a jumper cable, so that I can get home without the controller. As you said it is electronic and it will fail.
>If you want the controller send your address of list.
>Hank
>--------------------------------------------
>On Fri, 6/5/15, Alec Smyth via Personal_Submersibles < <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org> wrote:
>
>Subject: [PSUBS-MAILIST] Dive report: Snoopy at Seneca
>To: "Personal Submersibles General Discussion"
>< <mailto:personal_submersibles at psubs.org> personal_submersibles at psubs.org>
>Received: Friday, June 5, 2015, 6:16 PM
>
>Hello friends,
>I just got back from a dive trip to Seneca with Dan Lance and thought
>I'd share how it went. This was supposed to be a two sub trip with
>Scott Waters, but unfortunately a business emergency intervened and it
>ended up being just Snoopy.
>On the way up the weather was terrible, with driving rain so heavy I
>could barely see the lines on the road. It had been raining heavily for
>several days previously. Three times there were emergency announcements
>about floods, large hail, and damaging winds, and the closer I got the
>harder it rained. The problem with all that rain is that in your
>typical lake, the runoff ruins visibility for weeks. That is what
>happened last year when Trustworthy and Snoopy rendezvoused at
>Summersville Lake, and it looked very much like this would be a repeat.
>I'm happy to say Seneca must be rain-proof, because the deluge only
>reduced the visibility in the top fifty feet or so, and even those were
>clearer than most lakes.
>Here's a few things we learned:
>1) Of props and shroudsThe stern
>thruster speed control was dead on arrival, although I had tested it
>successfully before leaving. I opened up the enclosure, pressed down
>all the spade connectors, and found it now worked - so attributed the
>issue to road bumps.
>However, it died within a minute on the first dive. I had a spare speed
>controller, so switched it out.
>The replacement died within five minutes on the second dive. This time
>at least the cause was obvious, the prop was jammed by weeds. The
>current Minnkota props have a little twist at the end of the blades,
>and Snoopy's shroud is made with almost no clearance. The little twist
>to the blade tip causes any object coming between prop and shroud to
>jam tight, and had already smoked one controller during the convention
>in the Keys. I'm going to put the prop on the lathe and take off the
>tips to eliminate the pinching effect and to reduce the amperage draw a
>little so the motor goes lighter on the speed controller. By the way,
>the speed controller was protected by a fuse rated a little below the
>controller spec current draw, so perhaps those specs are optimistic.
>Anyway, as a result of the double failure all of our dives were done on
>just the side thrusters because I was out of spare speed controllers.
>Lesson for next sub: Design the electrical system with a controller
>bypass, so I can operate thrusters with simple on/off switches if a
>speed controller fails. They're electronic, they will fail.
>2) Of air bubbles in compensation oil
>Snoopy is now routinely diving deep (250 ft) and this has showed up a
>puzzling issue with the thrusters. They were feeble during dives, one
>died altogether on one dive, and they kept coming up leaking oil. At
>first we thought the seals were failing, perhaps due to some chemical
>incompatibility. We found suitable seals at an Amish farm supply store
>that sold things like tractor spares (viva trolling motor simplicity!)
>When I disconnected the bladder hose I got quite well sprayed with oil.
>The motor turned out to be pressurized.
>Previously, I thought if one had a small quantity of air left in the
>system it would not be an issue so long as the compression volume of
>that air could be handled by the flexibility of the hose (aka
>compensation bladder.) Wrong. I now think what happens is that if the
>dive exceeds the pressure rating of the shaft seal and there is a
>bubble of any size, you will get water added to the oil and the bubble
>stores the pressure. Upon surfacing, the bubble squeezes oil and water
>back out until the pressure in the motor falls to the "cracking
>pressure" of the seal. Thus, you get an oil leak even though the seals
>are fine. Lesson: Zero tolerance with oil bubbles, even a small bubble
>is unacceptable if you are diving deep. I'm going to put set screws on
>the motor caps so I can get rid of the bubbles more easily.
>3) An easy way to add
>buoyancySnoopy's buoyancy is adjusted by placing trawl floats in PVC
>tubes. On one occasion, the oncoming passenger's weight required the
>addition of just one float (i.e. the new guy weighed seven pounds more
>than the one getting off). The support diver wasn't suited up and the
>water was 42 degrees, so I just pushed a float under the lip of the
>forward MBT. It worked like a charm, and the float even stayed in place
>throughout the tow back to the ramp. Lesson: You can easily add a few
>floats for buoyancy on a standard K sub, no special tubes required.
>Most of our dives were along a very steep incline, not quite a wall but
>more like a series of ledges and very steep slopes. Between the steep
>terrain and the good visibility, the K250 dome for once offered a
>really good view. We typically made our way down the slopes using very
>slightly negative buoyancy, trailing the back corner of a skid on the
>slope. Looking aft, you could see a zigzagging trail of silt hanging
>motionless in the water and tracing our path. The sub compresses with
>depth, so slightly positive buoyancy at the surface turned into
>slightly negative at depth, but we're speaking of just a couple of
>pounds and not anything that caused difficulty. In fact at one point we
>stopped dead in the water four or five feet above a flat bottom for
>about five minutes, just waiting for a pre-arranged touch-point call on
>comms. The sub didn't rise or sink an inch, she just hung there
>completely immobile for five minutes. At about 140 feet the visibility
>would improve significantly, and the water changed from green to blue.
>It looked like ocean instead of lake water.
>I'll post a video, but that'll take a few days to put together. The
>only "incidents" we had were a cold bath we took when we closed the
>hatch over a corner of the crew's shirt, and when we got hooked on a
>log at 220 feet - fortunately reversing got us right off it.
>
>Best,
>Alec
>
>
>
>
>
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