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| RamRod Sword of Baal 2008-03-10, 3:25 am |
| Hey Mr. Daestrom, I seem to recall that you were on submarines, if my memory
serves me correctly.
Not sure if you were ever on diesel subs, as I have a questions about them.
Watching a submarine movie the other day (Das Boot) and I was thinking about
the driving mechanism.
Now I am aware that there are both diesel and electric motors on the sub,
but does the diesel engines drive the props directly or do they drive
generators that then drive the electric motors to drive the props when the
diesel engines are running??
I know that the diesels that do drive generators to charge the subs
batteries.
Just a curiosity question.
Thanks
| |
| Anthony Matonak 2008-03-10, 3:25 am |
| RamRod Sword of Baal wrote:
....
> Now I am aware that there are both diesel and electric motors on the
> sub, but does the diesel engines drive the props directly or do they
> drive generators that then drive the electric motors to drive the props
> when the diesel engines are running??
A quick search on google resulted in this webpage....
http://en.wikipedia.org/wiki/Submarine
To summarize, both ways were used. Early designs had the diesel and
electric both driving the prop. They used a clutch to disengage the
diesel when submerged. Newer designs use generators similar to a
railroad locomotive or serial hybrid car.
Anthony
| |
| RamRod Sword of Baal 2008-03-10, 1:25 pm |
|
"Anthony Matonak" <anthonym40@nothing.like.socal.rr.com> wrote in message
news:47d4c754$0$7021$4c368faf@roadrunner.com...
> RamRod Sword of Baal wrote:
> ...
>
> A quick search on google resulted in this webpage....
> http://en.wikipedia.org/wiki/Submarine
>
> To summarize, both ways were used. Early designs had the diesel and
> electric both driving the prop. They used a clutch to disengage the
> diesel when submerged. Newer designs use generators similar to a
> railroad locomotive or serial hybrid car.
>
> Anthony
Many thanks.
| |
| daestrom 2008-03-10, 8:25 pm |
|
"RamRod Sword of Baal" <Ramrod sword of Baal@truthonly.com> wrote in message
news:mc3Bj.24067$421.18529@news-server.bigpond.net.au...
> Hey Mr. Daestrom, I seem to recall that you were on submarines, if my
> memory serves me correctly.
>
>
>
> Not sure if you were ever on diesel subs, as I have a questions about
> them.
>
>
>
> Watching a submarine movie the other day (Das Boot) and I was thinking
> about the driving mechanism.
>
>
>
> Now I am aware that there are both diesel and electric motors on the sub,
> but does the diesel engines drive the props directly or do they drive
> generators that then drive the electric motors to drive the props when the
> diesel engines are running??
>
The 'fleet boats' of WWII and later were strictly 'electric drive'. The
shafts were turned by electric motors controlled from 'manuevering'. The
diesel engines drove generators only.
Just forward of the manuevering room was a large switchgear mechanism
controlled by links and rods inside manuevering room. Along with generator
controls, the watchstander could tie any number of diesel generators to the
'battery-bus' or the 'motor-bus' to charge the batteries or run the drive
motors. Boats had two main storage batteries that could be tied together in
various ways to drive the motors in series or parallel combinations for
either high speed underwater (well, not really very fast as the old boats
were not very streamlined), or long duration (expect to be under more than
12 hours).
daestrom
| |
| RamRod Sword of Baal 2008-03-11, 5:25 pm |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:47d5cadb$0$24120$4c368faf@roadrunner.com...
>
> "RamRod Sword of Baal" <Ramrod sword of Baal@truthonly.com> wrote in
> message news:mc3Bj.24067$421.18529@news-server.bigpond.net.au...
>
> The 'fleet boats' of WWII and later were strictly 'electric drive'. The
> shafts were turned by electric motors controlled from 'manuevering'. The
> diesel engines drove generators only.
>
> Just forward of the manuevering room was a large switchgear mechanism
> controlled by links and rods inside manuevering room. Along with
> generator controls, the watchstander could tie any number of diesel
> generators to the 'battery-bus' or the 'motor-bus' to charge the batteries
> or run the drive motors. Boats had two main storage batteries that could
> be tied together in various ways to drive the motors in series or parallel
> combinations for either high speed underwater (well, not really very fast
> as the old boats were not very streamlined), or long duration (expect to
> be under more than 12 hours).
>
> daestrom
Thank you
Out of curiosity, what sort of DC voltage were they?
I suppose it varied depending on how they were driven, but I guess the
batteries had to have a maximum voltage.
Thanks
| |
| daestrom 2008-03-12, 8:25 pm |
|
"RamRod Sword of Baal" <Ramrod sword of Baal@truthonly.com> wrote in message
news:HgBBj.24571$421.10616@news-server.bigpond.net.au...
>
> "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
> news:47d5cadb$0$24120$4c368faf@roadrunner.com...
>
> Thank you
>
>
> Out of curiosity, what sort of DC voltage were they?
>
> I suppose it varied depending on how they were driven, but I guess the
> batteries had to have a maximum voltage.
>
A single battery was about 125 individual cells arranged in series. With a
nominal 2.15 VDC per cell, that put the terminal voltage at about 268 VDC
when on 'float' or open circuit. The maximum voltage used for charging
depended on the temperature of the battery for 'normal' charges.
During 'equalizer' charges the limiting voltage was the equipment and
generators. Not supposed to go above 350, but I never saw it get close to
that.
daestrom
| |
| RW Salnick 2008-03-12, 8:25 pm |
| daestrom brought forth on stone tablets:
>
> "RamRod Sword of Baal" <Ramrod sword of Baal@truthonly.com> wrote in
> message news:HgBBj.24571$421.10616@news-server.bigpond.net.au...
>
>
> A single battery was about 125 individual cells arranged in series.
> With a nominal 2.15 VDC per cell, that put the terminal voltage at about
> 268 VDC when on 'float' or open circuit. The maximum voltage used for
> charging depended on the temperature of the battery for 'normal' charges.
>
> During 'equalizer' charges the limiting voltage was the equipment and
> generators. Not supposed to go above 350, but I never saw it get close
> to that.
>
> daestrom
>
There was an interesting thread on rec.boats.cruising about this a year
or so ago. One of the participants worked in a submarine battery
reconditioning shop. The current these cells could deliver was
impressive...
He talked about taking these batteries, which were in for
reconditioning, and removing the lead 'guts' from the cells (electrolyte
reclaimed in another step). Then before working on the lead plates it
was necessary to drain off the residual charge. They clamped a piece of
rebar across the terminals.
It got red hot...
bob
s/v Eolian
Seattle
| |
| RamRod Sword of Baal 2008-03-13, 1:26 pm |
|
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:47d86419$0$12560$4c368faf@roadrunner.com...
>
> "RamRod Sword of Baal" <Ramrod sword of Baal@truthonly.com> wrote in
> message news:HgBBj.24571$421.10616@news-server.bigpond.net.au...
>
> A single battery was about 125 individual cells arranged in series. With
> a nominal 2.15 VDC per cell, that put the terminal voltage at about 268
> VDC when on 'float' or open circuit. The maximum voltage used for
> charging depended on the temperature of the battery for 'normal' charges.
>
> During 'equalizer' charges the limiting voltage was the equipment and
> generators. Not supposed to go above 350, but I never saw it get close to
> that.
>
> daestrom
---------------------------
OK thanks for the info
Quite a lethal voltage, especially as it is DC.
| |
| daestrom 2008-03-13, 8:25 pm |
|
"RW Salnick" <salnick@no.spam.org> wrote in message
news:fr9out$3le$1@gnus01.u.washington.edu...
> daestrom brought forth on stone tablets:
>
> There was an interesting thread on rec.boats.cruising about this a year or
> so ago. One of the participants worked in a submarine battery
> reconditioning shop. The current these cells could deliver was
> impressive...
>
Yeah, the older nuc boat batteries were something like 1750A at the 3 hour
rate. The one hour rate is something like 4000A. The large Trident
submarines were about double that.
> He talked about taking these batteries, which were in for reconditioning,
> and removing the lead 'guts' from the cells (electrolyte reclaimed in
> another step). Then before working on the lead plates it was necessary to
> drain off the residual charge. They clamped a piece of rebar across the
> terminals.
>
> It got red hot...
>
While in the shipyard, one night a shipyard worker went into the battery
well to tighten some connections. Now normally, we sailors have a strict
rule that *nothing* made of metal longer than 6 inches is allowed in the
battery well. This is to avoid shorting cells of the battery together
(which is a *bad* thing). To tighten connectors, we have special torque
wrenches that are a metal 'head' but the handle and rest of it is made from
bakelite.
Another thing you need to know about submarine batteries is that they don't
just run the connections down one row and across and back up the other side.
This could result in a large 'loop' with large current flow (see above for
what 'large' is). That would create a pretty strong magnetic field that
could lead to magnitizing part of the hull and that would attract / detonate
magnetic mines. So the connections only go down a row of cells for four or
five cells and then jump over to another row. Go down that row a bit, then
jump back. So you have all sorts of jumpers criss-crossing rows and
'columns' in the compartment.
Well this 'yard worker' didn't know much about any of this, so he went into
the battery well with a nice 20 inch long torque wrench. (btw, to get around
in the battery well, you literally crawl on bakelite boards laid on top of
the battery). Needless to say he shorted between a couple of rows of cells
with his nice, shiny torque wrench. No fuses, no breakers, just hotter and
hotter and hotter. He climbs out and calls away for "Fire in the battery
well". Another electrician and I talk to him and (being young and foolish),
we decide to climb down in there and try to get the wrench free. We had to
both *kick* with all our might to break the thing free. It had 'welded'
onto the busbars and was much too hot to touch with our hands. We finally
got it out and ventilated the space. All that poor yardbird could think of
was he was going to have to pay for a new wrench (the socket, ratchet and
torsion bar on his was pretty well fused together).
Yes, they have a lot of stored energy.
daestrom
>
> bob
> s/v Eolian
> Seattle
| |
| Anthony Matonak 2008-03-14, 3:25 am |
| daestrom wrote:
....<snip bits about submarine batteries>...
> Yes, they have a lot of stored energy.
.... Enough to push a submarine. 
Anthony
--
Q: Why? How many volts in the third rail?
A: It's not the volts, it's the amps!
Q: OK, then. How many AMPS in the third rail?
A: Enough to push a train.
| |
| Solar Flare 2008-03-16, 1:26 pm |
| Interesting about the magnetic loop formed. Did anybody not decide there was
going to be one net loop, no matter how many time you twist the conductors
or loop them?
We have got into this crap many times over the years and I could see many
separate loops formed, having there own field, (providing large size usage)
but in the end only one large loop will ever be formed and only one can be
formed (net).
We had reports of overheating support strut irons on large conductors and it
took me about 1 second to ask if all phases went through the same loop of
mounting iron. Nice design by a very experienced E.E. with 30 years
experience in power distribution...LOL. Yup..he is well liked too...LOL
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:47d9c08b$0$24082$4c368faf@roadrunner.com...
>
> Another thing you need to know about submarine batteries is that they
> don't just run the connections down one row and across and back up the
> other side. This could result in a large 'loop' with large current flow
> (see above for what 'large' is). That would create a pretty strong
> magnetic field that could lead to magnitizing part of the hull and that
> would attract / detonate magnetic mines. So the connections only go down
> a row of cells for four or five cells and then jump over to another row.
> Go down that row a bit, then jump back. So you have all sorts of jumpers
> criss-crossing rows and 'columns' in the compartment.
>
> daestrom
>
| |
| daestrom 2008-03-16, 5:25 pm |
|
"Solar Flare" <solarflare@hotmale.invalid> wrote in message
news:TZidnWiuedgU0UDanZ2dnUVZ_siknZ2d@golden.net...
> Interesting about the magnetic loop formed. Did anybody not decide there
> was going to be one net loop, no matter how many time you twist the
> conductors or loop them?
>
> We have got into this crap many times over the years and I could see many
> separate loops formed, having there own field, (providing large size
> usage) but in the end only one large loop will ever be formed and only one
> can be formed (net).
>
But if you have several 'twists' in the loop, then each subloop is oriented
180 from the neighbor. So instead of one big loop forming one magnetic
field in one direction, you have it broken into small segments with the
field oriented up/down in each neighboring loop. Result is that from a
'distance', the twisted loop 'looks' like a much smaller magnetic field.
daestrom
| |
| Solar Flare 2008-03-17, 3:25 am |
| Not sure the descriptions are very communicative here...LOL
Unless you have one tangled mess you can never get more than one net loop
with a series circuit.
Also, you can never get less than one turn/loop either.
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:47dd9da5$0$16666$4c368faf@roadrunner.com...
>
> "Solar Flare" <solarflare@hotmale.invalid> wrote in message
> news:TZidnWiuedgU0UDanZ2dnUVZ_siknZ2d@golden.net...
>
> But if you have several 'twists' in the loop, then each subloop is
> oriented 180 from the neighbor. So instead of one big loop forming one
> magnetic field in one direction, you have it broken into small segments
> with the field oriented up/down in each neighboring loop. Result is that
> from a 'distance', the twisted loop 'looks' like a much smaller magnetic
> field.
>
> daestrom
>
| |
| daestrom 2008-03-17, 5:25 pm |
|
"Solar Flare" <solarflare@hotmale.invalid> wrote in message
news:vJCdnb8QP8A8QkDanZ2dnUVZ_rignZ2d@golden.net...
> Not sure the descriptions are very communicative here...LOL
>
Undoubtedly that is part of the problem.... :-)
> Unless you have one tangled mess you can never get more than one net loop
> with a series circuit.
>
> Also, you can never get less than one turn/loop either.
>
Take one large series loop. Now 'twist' the loop so it forms a figure
eight. Topologically speaking, you're right it is still just one loop.
Twist each subsection of the figure eight so that from above it looks like
four smaller circles. Again, from a graphing standpoint I agree it is still
just one 'loop'.
But the magnetic field from a current in a loop of wire has a *direction*
associated with it. Often, the right-hand rule is used to consistently note
the 'direction'. From a magneto-motive-force point of view, each smaller
section is an enclosed area of space with a current-carrying conductor
surrounding it. So when we apply the right-hand rule to find the direction
of the MMF associated with each section, we find that the direction of the
MMF is not always the same. Sometimes it points 'up', sometimes it points
'down'. Just like a racecar traveling around a figure-eight racetrack
sometimes has to turn left, and sometimes turns right, in some of these
subsections the current is traveling clockwise and sometimes anti-clockwise.
Still one 'loop', still one series circuit. And while the ampere-turns is
also the same for each of these subsections, each 'subsection' has a smaller
cross-sectional area so one would expect the MMF is concentrated into this
smaller area and a higher magnetic field strength would occur within one of
these 'subsections' as opposed to the original large single 'loop'.
But because half of the 'subsections' are oriented 180 out from the others,
when you start to move away from this arrangement, the magnetic field drops
off much faster than it would for a similar, non-twisted loop. As your
distance from any 'subsection' becomes much larger than the distance between
the two subsections, the combined effects of the two MMFs cancel each other
out. Much like if you measure the electric field between two charged
plates, it can be very high. But if you move away from them, as you get far
enough away so that the distance between the plates is 'small' in relation
to your distance from either plate, the field strength disappears because
the field strength from each plate 'cancels out' the others. Falls off
faster than simple inverse square law.
And that is the key reason for doing it, the magnetic field strength at some
distance is now weaker and less likely to trigger a magnetic trigger inside
an explosive mine.
Yes, if you look at the top of a submarine battery, it looks like a
snake/worm crawled over it. Go down a row three or four cells, jump to
another row (and that row jumps into your row). Cells are numbered from 1
at one end (say positive terminal), to 126 at the other bus connection
(negative terminal). So a battery well layout looks something like this.
(this is from memory, so it's probably wrong in some aspect but you should
get the idea. and it might not look very good in other fonts, sorry)....
94 95 126 XXX XXX 1 32 33
93 96 125 63 64 2 31 34
92 97 124 62 65 3 30 35
91 98 123 61 66 4 29 36
99 122 90 67 60 37 5 28
100 121 89 68 59 38 6 27
101 120 88 69 58 39 7 26
102 119 87 70 57 40 8 25
86 103 118 56 71 9 24 41
85 104 117 55 72 10 23 42
84 105 116 54 73 11 22 43
83 106 115 53 74 12 21 44
107 114 82 75 52 45 13 20
108 113 81 76 51 46 14 19
109 112 80 77 50 47 15 18
110 111 79 78 49 48 16 17
The 'XXX' are empty spots where there is no cell. This is the
entrance/scuttle that leads up out of the battery well. That's the only
place you can stand up. Cabling takes the positive and negative outputs
from cells 1 and 126. As you can see, yes there is a lot of cross-overs and
jumpers. A downside too is that some adjacent cells can have appreciable
voltage between them (for example, between cell 115 and 82 there are 33
cells, for a voltage of about 69 volts, don't short that together!!!).
daestrom
P.S. Although, as I look at this, ISTR that cells 1 and 126 should end up
on the same side near the entrance, so I may have this a bit wrong. It has
been a while.
| |
| Solar Flare 2008-03-17, 9:25 pm |
| Thanx for al that mess...LOL It may have been necessary but should took some
typing and decoding.
Not sure I understand the tangle reasoning but I understand the concept and
it was as I thought.
Electrician's nightmare. Where are those midgets when you need them?
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:47dedc30$0$16651$4c368faf@roadrunner.com...
>
> "Solar Flare" <solarflare@hotmale.invalid> wrote in message
> news:vJCdnb8QP8A8QkDanZ2dnUVZ_rignZ2d@golden.net...
>
> Undoubtedly that is part of the problem.... :-)
>
>
>
> Take one large series loop. Now 'twist' the loop so it forms a figure
> eight. Topologically speaking, you're right it is still just one loop.
> Twist each subsection of the figure eight so that from above it looks like
> four smaller circles. Again, from a graphing standpoint I agree it is
> still just one 'loop'.
>
> But the magnetic field from a current in a loop of wire has a *direction*
> associated with it. Often, the right-hand rule is used to consistently
> note the 'direction'. From a magneto-motive-force point of view, each
> smaller section is an enclosed area of space with a current-carrying
> conductor surrounding it. So when we apply the right-hand rule to find
> the direction of the MMF associated with each section, we find that the
> direction of the MMF is not always the same. Sometimes it points 'up',
> sometimes it points 'down'. Just like a racecar traveling around a
> figure-eight racetrack sometimes has to turn left, and sometimes turns
> right, in some of these subsections the current is traveling clockwise and
> sometimes anti-clockwise.
>
> Still one 'loop', still one series circuit. And while the ampere-turns is
> also the same for each of these subsections, each 'subsection' has a
> smaller cross-sectional area so one would expect the MMF is concentrated
> into this smaller area and a higher magnetic field strength would occur
> within one of these 'subsections' as opposed to the original large single
> 'loop'.
>
> But because half of the 'subsections' are oriented 180 out from the
> others, when you start to move away from this arrangement, the magnetic
> field drops off much faster than it would for a similar, non-twisted loop.
> As your distance from any 'subsection' becomes much larger than the
> distance between the two subsections, the combined effects of the two MMFs
> cancel each other out. Much like if you measure the electric field
> between two charged plates, it can be very high. But if you move away
> from them, as you get far enough away so that the distance between the
> plates is 'small' in relation to your distance from either plate, the
> field strength disappears because the field strength from each plate
> 'cancels out' the others. Falls off faster than simple inverse square
> law.
>
> And that is the key reason for doing it, the magnetic field strength at
> some distance is now weaker and less likely to trigger a magnetic trigger
> inside an explosive mine.
>
> Yes, if you look at the top of a submarine battery, it looks like a
> snake/worm crawled over it. Go down a row three or four cells, jump to
> another row (and that row jumps into your row). Cells are numbered from 1
> at one end (say positive terminal), to 126 at the other bus connection
> (negative terminal). So a battery well layout looks something like this.
> (this is from memory, so it's probably wrong in some aspect but you should
> get the idea. and it might not look very good in other fonts, sorry)....
>
> 94 95 126 XXX XXX 1 32 33
> 93 96 125 63 64 2 31 34
> 92 97 124 62 65 3 30 35
> 91 98 123 61 66 4 29 36
> 99 122 90 67 60 37 5 28
> 100 121 89 68 59 38 6 27
> 101 120 88 69 58 39 7 26
> 102 119 87 70 57 40 8 25
> 86 103 118 56 71 9 24 41
> 85 104 117 55 72 10 23 42
> 84 105 116 54 73 11 22 43
> 83 106 115 53 74 12 21 44
> 107 114 82 75 52 45 13 20
> 108 113 81 76 51 46 14 19
> 109 112 80 77 50 47 15 18
> 110 111 79 78 49 48 16 17
>
>
> The 'XXX' are empty spots where there is no cell. This is the
> entrance/scuttle that leads up out of the battery well. That's the only
> place you can stand up. Cabling takes the positive and negative outputs
> from cells 1 and 126. As you can see, yes there is a lot of cross-overs
> and jumpers. A downside too is that some adjacent cells can have
> appreciable voltage between them (for example, between cell 115 and 82
> there are 33 cells, for a voltage of about 69 volts, don't short that
> together!!!).
>
> daestrom
> P.S. Although, as I look at this, ISTR that cells 1 and 126 should end up
> on the same side near the entrance, so I may have this a bit wrong. It
> has been a while.
>
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