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Question (from a layman) about torque
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| scott.marquardt@gmail.com 2006-11-13, 3:25 am |
| I recently used a surplus windshield wiper motor in a drum coffee
roaster application. The drum has an 11 inch diameter, and the motor
can reliably do about 5 pounds of coffee beans. It's coupled with a
pulley that's almost 1:1 just now.
The drum has agitation vanes inside which are optimized to keep the
beans tossing about, but the simple picture is that they're being
lifted on a 5" radius (on average).
The drum's size easily allows for a 10 - 12 pound batch, but the motor
I've been using can't handle that at all.
What this layman needs is a bit of guidance on how to understand what
kind of torque specifications I should look for in a gearmotor that
will do the trick.
I'd be glad of any tips!
TIA
- S
| |
| William Noble 2006-11-13, 3:25 am |
| 1. windshield washer motor may not like running continuously - you want a
continuous duty motor
2. if I understand it right, you want to lift 12 pounds by 10 inches - to be
conservative, assume all the weight is at the extreme end of your 5 inch
radius, so you have 12X5 inch pounds of torque (e.g. 60 inch pounds or 5
foot pounds) of torque needed when the weight is exactly horizontal. I'd
probably add another 100% to that and look for 10 foot pounds of torque.
<scott.marquardt@gmail.com> wrote in message
news:1163399257.080856.255660@m73g2000cwd.googlegroups.com...
>I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
>
--
Posted via a free Usenet account from http://www.teranews.com
| |
| Rheilly Phoull 2006-11-13, 3:25 am |
| scott.marquardt@gmail.com wrote:
> I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
Has it gotta be a wiper or 12vdc motor?
Why not press into service a washing machine motor or the likes ?
--
Cheers ............. Rheilly P
| |
| David Billington 2006-11-13, 9:25 am |
|
scott.marquardt@gmail.com wrote:
>I recently used a surplus windshield wiper motor in a drum coffee
>roaster application. The drum has an 11 inch diameter, and the motor
>can reliably do about 5 pounds of coffee beans. It's coupled with a
>pulley that's almost 1:1 just now.
>
>The drum has agitation vanes inside which are optimized to keep the
>beans tossing about, but the simple picture is that they're being
>lifted on a 5" radius (on average).
>
>The drum's size easily allows for a 10 - 12 pound batch, but the motor
>I've been using can't handle that at all.
>
>What this layman needs is a bit of guidance on how to understand what
>kind of torque specifications I should look for in a gearmotor that
>will do the trick.
>
>I'd be glad of any tips!
>
>TIA
>
>- S
>
You might find a copy of the Bosch electric motor (aftermarket program)
catalogue useful. I have a printed copy, it may be available for
download or you may have to request one from a Bosch rep. Basically
lists all sorts of motors which I think derive from automotive
applications but which have a wider use. It give sizes, duty, voltage
and power consumption figures, torque curves. It may be helpful as you
might find the same or equivalent motor and may be able to find a more
powerful alternative.
Regarding William Noble's comment about duty cycle, those listed which
appear to be windscreen types are listed S1 duty (continuous) which
makes sense as it rains a lot in some parts of the world.
It might be worthwhile looking at a motor from a truck as they have
larger wipers but are likely to be 24V, at least they are typically in
the UK. Also the wiper motors are often only intended to run in one
direction and don't run as well in reverse so that may be worth checking
in your app.
| |
| David Billington 2006-11-13, 9:25 am |
| The power of google, searching for "bosch electric motor aftermarket" got
http://aa.bosch.de/advastaboschaa/C...B&publication=1
as the first hit and you can search through their online literature
about the various motors.
Hope that helps.
David Billington wrote:
>
>
> scott.marquardt@gmail.com wrote:
>
> You might find a copy of the Bosch electric motor (aftermarket
> program) catalogue useful. I have a printed copy, it may be available
> for download or you may have to request one from a Bosch rep.
> Basically lists all sorts of motors which I think derive from
> automotive applications but which have a wider use. It give sizes,
> duty, voltage and power consumption figures, torque curves. It may be
> helpful as you might find the same or equivalent motor and may be able
> to find a more powerful alternative.
>
> Regarding William Noble's comment about duty cycle, those listed
> which appear to be windscreen types are listed S1 duty (continuous)
> which makes sense as it rains a lot in some parts of the world.
>
> It might be worthwhile looking at a motor from a truck as they have
> larger wipers but are likely to be 24V, at least they are typically in
> the UK. Also the wiper motors are often only intended to run in one
> direction and don't run as well in reverse so that may be worth
> checking in your app.
>
| |
|
| I think you guys missed the point, he has a wiper motor, and wants to know
how to select a commercial gearmotor replacement that will be suitable.
<scott.marquardt@gmail.com> wrote in message
news:1163399257.080856.255660@m73g2000cwd.googlegroups.com...
>I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
>
| |
| Roger_N 2006-11-13, 9:25 am |
| If you have 12 pounds of coffee beans at 6" radius (1/2 foot for easy math)
it would take 6 foot pounds of torque. I don't know what your ideal RPM is
but I'll attempt to calculate approximate HP at 30 RPM.
30 RPM is 1/2 rev per second, at 5 inch radius I'll estimate 1-1/2 feet per
second
6 pounds of torque at 1.5 fps = 9 ft/lbs/second.
IIRC 1 HP = 550 ft/lbs/second. So you need 0.0164 HP, or 1/61 HP for 30
rpm, scale for the actual rpm you intend to use. Since gearboxes, bearings,
etc are not 100% efficient, upsize a bit from this. I would look for
something perhaps 1/40 HP or larger. Since 746 Watts = 1 HP, you need a
little over 12 Watts of motor power @100% efficiency, a 1/40 HP motor =
18.65Watts (not actual electricity usage, output HP, some motors are rated
in HP, some in Watts).
Gearing - What you have / what you want.
If you find a 1750 RPM motor and want 30 RPM, 1750/30 = 58.33, you would
look for somewhere around a 60:1 gearbox.
To just answer your torque question, you need around 6 ft /lbs, or 72
in/lbs, or 1152 in/oz of torque at the drum.
Hope this helps
RogerN
<scott.marquardt@gmail.com> wrote in message
news:1163399257.080856.255660@m73g2000cwd.googlegroups.com...
>I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
>
| |
|
| scott.marquardt@gmail.com wrote:
> I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
>
Adding to what Roger said about gearing down to reduce
RPM: when you gear down to reduce speed, you multiply
the torque that the motor can deliver by the same ratio
as you geard down the rpm. So, for example, say you
gear down to reduce the speed to 1 tenth. That makes
your motor effectively 10 times stronger. A 100 RPM
motor capable of delivering 1 foot pound of torque geared
down to 10 RPM will deliver 10 foot pounds of torque through
the gears. There will be some loss due to friction,
so the actual delivered torque will be something a bit
under 10 foot pounds.
Ed
| |
| Paul M 2006-11-13, 5:25 pm |
| On Mon, 13 Nov 2006 19:22:44 GMT, ehsjr <ehsjr@bellatlantic.net>
proclaimed to the world:
>Adding to what Roger said about gearing down to reduce
>RPM: when you gear down to reduce speed, you multiply
>the torque that the motor can deliver by the same ratio
>as you geard down the rpm. So, for example, say you
>gear down to reduce the speed to 1 tenth. That makes
>your motor effectively 10 times stronger. A 100 RPM
>motor capable of delivering 1 foot pound of torque geared
>down to 10 RPM will deliver 10 foot pounds of torque through
>the gears. There will be some loss due to friction,
>so the actual delivered torque will be something a bit
>under 10 foot pounds.
>
>Ed
This reminded me of my past in the US Navy. I took care of the main
engine controls on the last conventional powered aircraft carrier
built. It has four main engines consisting of huge GE steam turbines.
The reduction gears tower above you. All that turbine torque reduced
down to less than 100 rpm to a 30 inch drive shafts. There is no
clutch or reverse. A separate turbine drives the whole thing in
reverse. Anyway, the weight of the drive shafts and span between
bearing blocks made it necessary to slowly turn the shafts while in
port to keep the shafts from sagging. We "jacked" the turbine,
reduction gears and main shaft with a fractional HP electric motor.
Because we could connect the jacking motor to a huge ring gear on one
of the turbine's larger rotors, there is little gearing loss.
One night while looking down into the dry dock, I had a vision of the
worlds largest barbecue pit, with a tied and spittled Godzilla slowly
turning over the fire. In this application the jacking gear would have
to be sped up or the big lizard would get burnt on one side. I don't
remember the exact turn rate anymore. I knew then. It's somewhere
around 2 RPD.
| |
| Salmon Egg 2006-11-13, 8:25 pm |
| On 11/12/06 10:27 PM, in article
1163399257.080856.255660@m73g2000cwd.googlegroups.com,
"scott.marquardt@gmail.com" <scott.marquardt@gmail.com> wrote:
> I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
>
Read a high school level physics book on simple machines.
Bill
-- Fermez le Bush
| |
| woodworker88 2006-11-13, 8:25 pm |
| This won't solve the problem, but one place to start would be to
measure the torque you have. Since torque is measured in foot-lbs, you
just need to measure the force exerted by a lever-arm one foot long.
Make up a bar with a distance of one foot from the motor shaft to a
large hole at the other end. Then connect a spring scale (such as a
fish scale) to the large hole and secure the scale and the motor to a
firm bench or something. Turn on the motor and read the force on the
scale. This is the stall torque of the motor. If I remember
correctly, a rough estimate for optimum power is between 65% and 80% of
the stall torque. The exact value for the optimum power is measurable
from the motor torque curves, but these may be hard to find for a
surplus motor.
Hope this helps you get a handle on what you have now.
ww88
scott.marquardt@gmail.com wrote:
> I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
>
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
>
> I'd be glad of any tips!
>
> TIA
>
> - S
| |
| Michael A. Terrell 2006-11-14, 9:25 am |
| Paul M wrote:
>
> On Mon, 13 Nov 2006 19:22:44 GMT, ehsjr <ehsjr@bellatlantic.net>
> proclaimed to the world:
>
>
> This reminded me of my past in the US Navy. I took care of the main
> engine controls on the last conventional powered aircraft carrier
> built. It has four main engines consisting of huge GE steam turbines.
> The reduction gears tower above you. All that turbine torque reduced
> down to less than 100 rpm to a 30 inch drive shafts. There is no
> clutch or reverse. A separate turbine drives the whole thing in
> reverse. Anyway, the weight of the drive shafts and span between
> bearing blocks made it necessary to slowly turn the shafts while in
> port to keep the shafts from sagging. We "jacked" the turbine,
> reduction gears and main shaft with a fractional HP electric motor.
> Because we could connect the jacking motor to a huge ring gear on one
> of the turbine's larger rotors, there is little gearing loss.
>
> One night while looking down into the dry dock, I had a vision of the
> worlds largest barbecue pit, with a tied and spittled Godzilla slowly
> turning over the fire. In this application the jacking gear would have
> to be sped up or the big lizard would get burnt on one side. I don't
> remember the exact turn rate anymore. I knew then. It's somewhere
> around 2 RPD.
How about roasting a bunch of lawyers instead of Godzilla? ;-)
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
| |
| Jerry Avins 2006-11-14, 9:25 am |
| Paul M wrote:
> On Mon, 13 Nov 2006 19:22:44 GMT, ehsjr <ehsjr@bellatlantic.net>
> proclaimed to the world:
>
>
> This reminded me of my past in the US Navy. I took care of the main
> engine controls on the last conventional powered aircraft carrier
> built. It has four main engines consisting of huge GE steam turbines.
> The reduction gears tower above you. All that turbine torque reduced
> down to less than 100 rpm to a 30 inch drive shafts. There is no
> clutch or reverse. A separate turbine drives the whole thing in
> reverse. Anyway, the weight of the drive shafts and span between
> bearing blocks made it necessary to slowly turn the shafts while in
> port to keep the shafts from sagging. We "jacked" the turbine,
> reduction gears and main shaft with a fractional HP electric motor.
> Because we could connect the jacking motor to a huge ring gear on one
> of the turbine's larger rotors, there is little gearing loss.
>
> One night while looking down into the dry dock, I had a vision of the
> worlds largest barbecue pit, with a tied and spittled Godzilla slowly
> turning over the fire. In this application the jacking gear would have
> to be sped up or the big lizard would get burnt on one side. I don't
> remember the exact turn rate anymore. I knew then. It's somewhere
> around 2 RPD.
I'm not sure that the stated reason for "jacking" is correct. Many power
plants use gas turbines to run peaking generators for short-term loads
When those are idle, they are kept moving slowly by "turning gear"
(different industry, different name). The purpose is not to prevent the
steel shafts of alternator and turbine from taking a set, but to keep
oil from being squeezed out of the lower parts of the bearings by steady
unidirectional pressure. Some modern installations use pumps to force
oil flow even when the shafts are stationary. This has the advantage
that recovery from power failure is simpler and safer.
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| Paul M 2006-11-14, 1:25 pm |
| On Tue, 14 Nov 2006 10:21:49 -0500, Jerry Avins <jya@ieee.org>
proclaimed to the world:
>I'm not sure that the stated reason for "jacking" is correct. Many power
>plants use gas turbines to run peaking generators for short-term loads
>When those are idle, they are kept moving slowly by "turning gear"
>(different industry, different name). The purpose is not to prevent the
>steel shafts of alternator and turbine from taking a set, but to keep
>oil from being squeezed out of the lower parts of the bearings by steady
>unidirectional pressure. Some modern installations use pumps to force
>oil flow even when the shafts are stationary. This has the advantage
>that recovery from power failure is simpler and safer.
>
>Jerry
From my experience, I suspect that rotor warping is as much a reason
for turning those gas turbines. I've do some work with gas turbines in
both the power generation and marine industries. BTW "turning gear" is
also used in the marine field, more so in the merchant marines than
Military. I know the Brits have some odd names for things too.
My stated reason for jacking the turbine and power transmission system
in a marine propulsion system is only one of several. There may be
more but here are the ones I know of.
1. Drive shaft sag
2. Lubrication
3. Warping of the turbine due to temperature variation.
Lubrication was never a big issue that I knew of other than making
sure that the pumps were on and you had pressure at the bearings
before you started jacking. There were several conditions we keep the
engine in which had to do with the amount of time it took to turn
screws under power. The most "shut down" state was with no oil to the
bearing, no jacking. With a completely cold main engine turbine it
took around a day to warm it up to the point where the throttle valve
was cracked open. I remember a few times where we pushed the edge of
safely when we had to get underway unexpectedly. Shaft sag posed the
possibility of the longest delay. We kept logs of when and how long we
jacked and had a setup to measure the shaft sag. There are times when
it is unavoidable and the shafts had to stay in the same position.
They do not sag all at once of course. I saw a graph of shaft sag once
and remember that sag is a curve with sag decreasing with time. After
several weeks the shafts are as bent as they are going to get. It
takes several weeks of straightening to get underway. This is
unacceptable for a combat ship, so they jack the shaft as a rule, only
letting it set when necessary, such as when in overhaul.
It might be a good idea for me to add that the jacking gear was
sometimes used intermittently.Some ships had two speeds. We might
want to keep the shaft stationary most of the time, so we would jack
the shafts 180 degrees ever few days. The longest shaft is over 200
ft. I was told that this shaft has 2 1/2 twists in it when under full
load. I find this difficult to believe, but the guy who told me was
pretty credible, as he was one of the naval engineers working on
refurbishing the bearing blocks for the shaft. It gives you a better
idea of the flexibility of these shafts.
Keep on questioning things Jerry. It gives me the opportunity to
babble more. :-)
| |
| Steve Ackman 2006-11-14, 5:25 pm |
| ["Followup-To:" header set to rec.crafts.metalworking.]
In <1163399257.080856.255660@m73g2000cwd.googlegroups.com>, on 12 Nov
2006 22:27:37 -0800, scott.marquardt@gmail.com wrote:
> I recently used a surplus windshield wiper motor in a drum coffee
> roaster application. The drum has an 11 inch diameter, and the motor
> can reliably do about 5 pounds of coffee beans. It's coupled with a
> pulley that's almost 1:1 just now.
>
> The drum has agitation vanes inside which are optimized to keep the
> beans tossing about, but the simple picture is that they're being
> lifted on a 5" radius (on average).
> The drum's size easily allows for a 10 - 12 pound batch, but the motor
> I've been using can't handle that at all.
>
> What this layman needs is a bit of guidance on how to understand what
> kind of torque specifications I should look for in a gearmotor that
> will do the trick.
Once you load the drum up, you'll have more coffee
in toward the center of the drum so your average
moment will decrease. Also in the light load, all
your beans are carried up beyond horizontal on the
vanes before they spill back to the bottom while the
larger load has much more of a rolling effect. You
still have the same amount of beans riding the vanes
up to horizontal, but you also have a mass that's
just rolling around the bottom... it's only rising
from something like 180° to 230°. Obviously, this is all
highly dependent on rpm, and how close that comes to
the sticking speed for that radius. Even if I knew
all the variables, I wouldn't know the math of it.
In this sort of application, I don't think that
doubling the load necessarily requires doubling the
torque though.
My Millenium uses a 3/4 hp motor to rotate 15kg of
beans in 15" drum at 57 rpm, and it's not even a
strain. I have to guess that it does require more
than 1/2 hp though, or they would have cheaped out
on the lighter motor. (The blower motor is 1/2 hp,
for instance)
Purely back of the napkin then, and ignoring other
variables I know about and others I can't imagine,
your drum is .733 the radius of mine x .333 the load of
mine, so should require roughly 1/4 the torque.
I'm going to guess that 1/6 hp ought to be more than
enough @ 60 rpm or 1/12 hp @ 30 rpm...
| |
| Jerry Avins 2006-11-14, 5:25 pm |
| Paul M wrote
interesting information and
> Keep on questioning things Jerry. It gives me the opportunity to
> babble more. :-)
I stand corrected.
I have a collimator that fastens into the bore of my rifle and provides
a target for the scope. I can remove the scope from the barrel and the
barrel from the receiver, then align the scope to the collimator's
projected image at reassembly and it is dead on *provided the barrel is
right-side up and level when the adjustment is made.* The weight of the
barrel and collimator flexes the barrel enough to throw the sight line
off otherwise. My barrel is about two feet long and 3/4" in diameter,
with a 15/64" (.22 cal.) bore, yet it flexes enough to throw the sights
way off is not used gingerly.
I drove a '50 jaguar XK-120 that had such a hard-grabbing clutch that
nobody I knew, not even the dealer's mechanic, could slip the clutch a
bit without chattering vigorously. (That's why it sold cheap.) The drive
shaft was about 1.25" at the clutch spline, tapering uniformly down to
3/4" at the differential. My way to start the caw was sliding my foot
sideways off the pedal so the clutch didn't have time to chatter, and
rely on the drive shaft's windup to absorb the shock. The shaft probably
wound up two turns before the car moved an inch, then unwound, returning
the stored energy to forward momentum. Properly playing the accelerator
avoided oscillation. That car started like a goosed antelope!
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| Paul M 2006-11-14, 5:25 pm |
| On Tue, 14 Nov 2006 14:52:32 -0500, Jerry Avins <jya@ieee.org>
proclaimed to the world:
>Properly playing the accelerator
>avoided oscillation. That car started like a goosed antelope!
I hope the car had head rests. I would imagine that having your head
against the rest made the start a bit better. Forget the coffee.
BTW a fine clutch and gearbox is a real joy. Coupled to a beefy engine
it really is a treat. I really should have become a rally racer.
| |
|
| In article <qr9kl2dc9n86j7b5ps7d4hhd9brmedn0a2@4ax.com>,
Paul M <PaulMatWiredogdotcom> wrote:
> On Tue, 14 Nov 2006 14:52:32 -0500, Jerry Avins <jya@ieee.org>
> proclaimed to the world:
>
>
> I hope the car had head rests. I would imagine that having your head
> against the rest made the start a bit better. Forget the coffee.
>
> BTW a fine clutch and gearbox is a real joy. Coupled to a beefy engine
> it really is a treat. I really should have become a rally racer.
My son has a one year old Mazda 6. I have a 15 yr old Jeep. I can beat
him off the line for the first 50 feet or so. He then smokes me. Torque
is what makes the Jeep jump out ahead.
Al
| |
| Paul M 2006-11-15, 9:25 am |
| On Wed, 15 Nov 2006 14:16:25 GMT, Al <no.spam@wanted.com> proclaimed
to the world:
>In article <qr9kl2dc9n86j7b5ps7d4hhd9brmedn0a2@4ax.com>,
> Paul M <PaulMatWiredogdotcom> wrote:
>
>
>My son has a one year old Mazda 6. I have a 15 yr old Jeep. I can beat
>him off the line for the first 50 feet or so. He then smokes me. Torque
>is what makes the Jeep jump out ahead.
>
>Al
In younger years I had a Suzuki 380 motorcycle. It was a hot 2 stroke
back in the 70's. I used to street drag race with it against all the
Hondas around then. The Honda 360 and 550 were really popular four
stroke bikes back then and had more torque than most. The two strokes
were laughed at then but they had a lot of top end. For me to beat a
550 Honda, I had to due a burnout start, hell to get off the line, I
had to do this. On the start the Honda would get maybe twenty feet
ahead while I was leaning over the handle bars, leaving a cloud of
smoke with the tire. Once I got moving a bit, I would lean back and
transfer weight to the tire. The bike would squat, the front wheel
would come up and the tire would stick. It was like being shot from a
cannon. At around 150 ft off the line, I would shoot by the Honda like
it was standing still.
Now I have a old Honda CX500 touring bike with lots of torque. Torque
is better than speed for day after day pleasure in driving.
| |
| Jerry Avins 2006-11-15, 1:25 pm |
| Al wrote:
> In article <qr9kl2dc9n86j7b5ps7d4hhd9brmedn0a2@4ax.com>,
> Paul M <PaulMatWiredogdotcom> wrote:
>
>
> My son has a one year old Mazda 6. I have a 15 yr old Jeep. I can beat
> him off the line for the first 50 feet or so. He then smokes me. Torque
> is what makes the Jeep jump out ahead.
The Jag belonged to a friend. It had the same weight, engine
displacement, and cylinder count (6) and as my father's '50 Dodge sedan.
Not much similarity beyond that.
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| scott.marquardt@gmail.com 2006-11-16, 3:25 am |
|
Steve Ackman wrote:
> Purely back of the napkin then, and ignoring other
> variables I know about and others I can't imagine,
> your drum is .733 the radius of mine x .333 the load of
> mine, so should require roughly 1/4 the torque.
Thanks to Steve and everyone else for the sound counsel.
As a Navy vet myself, I don't mind the sea stories either. ;-)
- Scott
| |
| daestrom 2006-11-19, 1:25 pm |
|
"Paul M" <PaulMatWiredogdotcom> wrote in message
news:7gvjl2pmuos47n5kpm41afe83886gdvr0m@4ax.com...
> On Tue, 14 Nov 2006 10:21:49 -0500, Jerry Avins <jya@ieee.org>
> proclaimed to the world:
>
>
> From my experience, I suspect that rotor warping is as much a reason
> for turning those gas turbines. I've do some work with gas turbines in
> both the power generation and marine industries. BTW "turning gear" is
> also used in the marine field, more so in the merchant marines than
> Military. I know the Brits have some odd names for things too.
>
>
> My stated reason for jacking the turbine and power transmission system
> in a marine propulsion system is only one of several. There may be
> more but here are the ones I know of.
>
> 1. Drive shaft sag
> 2. Lubrication
> 3. Warping of the turbine due to temperature variation.
>
> Lubrication was never a big issue that I knew of other than making
> sure that the pumps were on and you had pressure at the bearings
> before you started jacking. There were several conditions we keep the
> engine in which had to do with the amount of time it took to turn
> screws under power. The most "shut down" state was with no oil to the
> bearing, no jacking. With a completely cold main engine turbine it
> took around a day to warm it up to the point where the throttle valve
> was cracked open. I remember a few times where we pushed the edge of
> safely when we had to get underway unexpectedly. Shaft sag posed the
> possibility of the longest delay. We kept logs of when and how long we
> jacked and had a setup to measure the shaft sag. There are times when
> it is unavoidable and the shafts had to stay in the same position.
> They do not sag all at once of course. I saw a graph of shaft sag once
> and remember that sag is a curve with sag decreasing with time. After
> several weeks the shafts are as bent as they are going to get. It
> takes several weeks of straightening to get underway. This is
> unacceptable for a combat ship, so they jack the shaft as a rule, only
> letting it set when necessary, such as when in overhaul.
>
> It might be a good idea for me to add that the jacking gear was
> sometimes used intermittently.Some ships had two speeds. We might
> want to keep the shaft stationary most of the time, so we would jack
> the shafts 180 degrees ever few days. The longest shaft is over 200
> ft. I was told that this shaft has 2 1/2 twists in it when under full
> load. I find this difficult to believe, but the guy who told me was
> pretty credible, as he was one of the naval engineers working on
> refurbishing the bearing blocks for the shaft. It gives you a better
> idea of the flexibility of these shafts.
>
> Keep on questioning things Jerry. It gives me the opportunity to
> babble more. :-)
>
On boats (submarines), we too had to run the turning gear. But the drive
shaft was much shorter and sag wasn't much of an issue. Steam turbine rotor
bending was more the concern, due to uneven heating (cold condenser below,
and sealing steam applied to the shaft's labyrinth seals). If completely
'cold', like from an IMA or overhaul, we had to run the oil for a day or so
just to warm it up to the minimum for jacking (90 F IIRC, for 2190 turbine
oil). Then put the turbine/gear on the the 'jack' for four hours before
bringing steam into the engine room and applying steam to the shaft seals,
or warming the engine.
Lubrication on relatively small turbines (just a couple of ton rotors) is a
matter of just having low-pressure oil supply and letting a dry shaft 'ride
up' one side of the journal. It quickly pulls a film of oil under the
shaft.
Large commercial turbines (on the order of 50 ton) also have 'lift pumps'.
Along the with the low-pressure lubricating oil, a 'lift pump' supplies high
pressure oil (>100 PSI) to a special port in the lower half of the bearing
sleeve. It is enough pressure to force an oil film under the shaft, even
when it isn't turning. So prior to first starting the turning gear, the
lift pumps are used to 'break free' the shaft from the bearing sleeves.
Quite often, once the shaft is turning (with the turning gear), the lift
pumps can be secured as the oil film around the shaft is then enough to
allow continued turning with the small motor.
daestrom
>
>
| |
| Paul M 2006-11-19, 1:25 pm |
| On Sun, 19 Nov 2006 18:24:50 GMT, "daestrom"
<daestrom@NO_SPAM_HEREtwcny.rr.com> proclaimed to the world:
[color=darkred]
>
>"Paul M" <PaulMatWiredogdotcom> wrote in message
>news:7gvjl2pmuos47n5kpm41afe83886gdvr0m@4ax.com...
>
>On boats (submarines), we too had to run the turning gear. But the drive
>shaft was much shorter and sag wasn't much of an issue. Steam turbine rotor
>bending was more the concern, due to uneven heating (cold condenser below,
>and sealing steam applied to the shaft's labyrinth seals). If completely
>'cold', like from an IMA or overhaul, we had to run the oil for a day or so
>just to warm it up to the minimum for jacking (90 F IIRC, for 2190 turbine
>oil). Then put the turbine/gear on the the 'jack' for four hours before
>bringing steam into the engine room and applying steam to the shaft seals,
>or warming the engine.
>
>Lubrication on relatively small turbines (just a couple of ton rotors) is a
>matter of just having low-pressure oil supply and letting a dry shaft 'ride
>up' one side of the journal. It quickly pulls a film of oil under the
>shaft.
>
>Large commercial turbines (on the order of 50 ton) also have 'lift pumps'.
>Along the with the low-pressure lubricating oil, a 'lift pump' supplies high
>pressure oil (>100 PSI) to a special port in the lower half of the bearing
>sleeve. It is enough pressure to force an oil film under the shaft, even
>when it isn't turning. So prior to first starting the turning gear, the
>lift pumps are used to 'break free' the shaft from the bearing sleeves.
>Quite often, once the shaft is turning (with the turning gear), the lift
>pumps can be secured as the oil film around the shaft is then enough to
>allow continued turning with the small motor.
>
>daestrom
>
I appreciate you posting this. My main duties involved the
instrumentation and controls of both the boilers and main engines, but
my rate was boiler tech. The shop I worked in had both boiler tech and
machinist mates. The main engines had very little controls. I am sure
this is the same with your sub. I did a lot of work on subs after I
got out of the Navy and worked as a private contractor. The steam
cycle remains the same as did the turbines which used the power
produced by whatever source, be it conventional or nuke. Anyway, I was
hesitant to post any info on main bearing lubrication with sketchy
memory. Jerry spends late nights checking all my facts.:-) (Just
kidding Jerry. I appreciate every question you pose.) Anyway I vaguely
remember the lift pumps and decided not to mention them fearing I
might not be accurate. Thanks for filling in the details. Do you
remember what the lift pump pressures were?
I remember one time where the labyrinth packing was damaged by someone
incorrectly jacking. I also remember uncoupling the main shaft so we
could jack the turbine while the shaft was down.
You don't happen to remember how big the shafts were on the sub, do
you? I remember on tridents and the sea wolf, the shafts appeared to
be much smaller. It seems a little silly today but this might still be
classified. Which class of sub did you serve on?
| |
| daestrom 2006-11-21, 5:25 pm |
|
"Paul M" <PaulMatWiredogdotcom> wrote in message
news:9l81m292tebitl4hbqpni85fo1m0jglgu7@4ax.com...
> On Sun, 19 Nov 2006 18:24:50 GMT, "daestrom"
> <daestrom@NO_SPAM_HEREtwcny.rr.com> proclaimed to the world:
>
>
> I appreciate you posting this. My main duties involved the
> instrumentation and controls of both the boilers and main engines, but
> my rate was boiler tech. The shop I worked in had both boiler tech and
> machinist mates. The main engines had very little controls. I am sure
> this is the same with your sub. I did a lot of work on subs after I
> got out of the Navy and worked as a private contractor. The steam
> cycle remains the same as did the turbines which used the power
> produced by whatever source, be it conventional or nuke. Anyway, I was
> hesitant to post any info on main bearing lubrication with sketchy
> memory. Jerry spends late nights checking all my facts.:-) (Just
> kidding Jerry. I appreciate every question you pose.) Anyway I vaguely
> remember the lift pumps and decided not to mention them fearing I
> might not be accurate. Thanks for filling in the details. Do you
> remember what the lift pump pressures were?
>
Commercial turbine lift pumps run about 100 psi (relief set for 120). But
they're positive displacement (little versions of a typical 'gear' pump), so
the exact pressure depends on the weight of the shaft and the
temperature/viscosity of the oil.
> I remember one time where the labyrinth packing was damaged by someone
> incorrectly jacking. I also remember uncoupling the main shaft so we
> could jack the turbine while the shaft was down.
>
We had it 'both ways'. The main reduction gear output could be disconnected
from the shaft so the turbines/gear could be jacked without turning the
shaft (a big-a__ clutch). Then each turbine shaft had a 'hard' coupling
that could be disconnected between each turbine and the gear (port-starboard
main turbines fed one reduction gear). That was in case a turbine was
damaged, you could spin the shaft from the opposite turbine at reduced
bells.
> You don't happen to remember how big the shafts were on the sub, do
> you? I remember on tridents and the sea wolf, the shafts appeared to
> be much smaller. It seems a little silly today but this might still be
> classified. Which class of sub did you serve on?
Don't know if it was ever classified, I'm sure the hp rating was. As I
recall, they were only about 18" to 20" across, much smaller than your
carrier version (and shorter too). The trickiest part of them was the
seals, we didn't use 'packing gland' type, but the 'mechanical seal' type in
order to adapt to changing depth/sea-pressure.
Tridents? SeaWolf? HA!!! Luxury liners!! Try 'boring holes in the ocean'
in 'Permit' class. Yes, those are the ones with *miles* of seawater piping
and were originally named 'Thresher' class. ("fast and black, and never
come back")
daestrom
former EMC(SS)
| |
| Jerry Avins 2006-11-21, 5:25 pm |
| daestrom wrote:
...
> Tridents? SeaWolf? HA!!! Luxury liners!! Try 'boring holes in the
> ocean' in 'Permit' class. Yes, those are the ones with *miles* of
> seawater piping and were originally named 'Thresher' class. ("fast and
> black, and never come back")
I remember Thresher being lost, and I remember how surprised some
experts were when she was ultimately found nearly intact. I recall a
seminar at which it was claimed that she was probably scattered in small
pieces over a wide area. "... never came back." Were there other losses?
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| Paul M 2006-11-21, 8:25 pm |
| On Tue, 21 Nov 2006 21:11:30 GMT, "daestrom"
<daestrom@NO_SPAM_HEREtwcny.rr.com> proclaimed to the world:
>Tridents? SeaWolf? HA!!! Luxury liners!! Try 'boring holes in the ocean'
>in 'Permit' class. Yes, those are the ones with *miles* of seawater piping
>and were originally named 'Thresher' class. ("fast and black, and never
>come back")
>
>daestrom
>former EMC(SS)
I never even got to see any of those subs except along the docks at
the sub piers sitting near the old diesels. I guess they were built to
last without much repair. ;-)
And those luxury liners were not so luxurious when ripped apart in dry
dock, particularly since I was there to work on storage tank level
indicator/controls. They would never tell me what "CHT" stood for. It
must be classified. (LOL) I figured it must be "Chocolate Heaven Tank"
from the looks of what was left in the tank when we got to it. To tell
the truth, I also worked on a lot of other stuff too.
| |
| Jerry Avins 2006-11-21, 8:25 pm |
| Paul M wrote:
> On Tue, 21 Nov 2006 21:11:30 GMT, "daestrom"
> <daestrom@NO_SPAM_HEREtwcny.rr.com> proclaimed to the world:
>
>
> I never even got to see any of those subs except along the docks at
> the sub piers sitting near the old diesels. I guess they were built to
> last without much repair. ;-)
>
> And those luxury liners were not so luxurious when ripped apart in dry
> dock, particularly since I was there to work on storage tank level
> indicator/controls. They would never tell me what "CHT" stood for. It
> must be classified. (LOL) I figured it must be "Chocolate Heaven Tank"
> from the looks of what was left in the tank when we got to it. To tell
> the truth, I also worked on a lot of other stuff too.
"Collection and Holding Tank" If the odor didn't provide a hint, there
mist have been some powerful chemicals, too.
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| Paul M 2006-11-21, 8:25 pm |
| On Tue, 21 Nov 2006 19:03:39 -0500, Jerry Avins <jya@ieee.org>
proclaimed to the world:
>"Collection and Holding Tank" If the odor didn't provide a hint, there
>mist have been some powerful chemicals, too.
>
>Jerry
I know what it stands for Jerry. It was a joke.
And actually it stands for Collection, Holding and Transfer tank.
| |
| Ursa Major 2006-11-21, 8:25 pm |
|
"Paul M" <PaulMatWiredogdotcom> wrote in message
news:lh57m2lmuhbg4pofd5v45nos7q7ibndheo@4ax.com...
> On Tue, 21 Nov 2006 19:03:39 -0500, Jerry Avins <jya@ieee.org>
> proclaimed to the world:
>
>
> I know what it stands for Jerry. It was a joke.
*snicker*
> And actually it stands for Collection, Holding and Transfer tank.
| |
| Paul M 2006-11-21, 8:25 pm |
| On Tue, 21 Nov 2006 19:30:37 -0500, Paul M <PaulMatWiredogdotcom>
proclaimed to the world:
>On Tue, 21 Nov 2006 19:03:39 -0500, Jerry Avins <jya@ieee.org>
>proclaimed to the world:
>
>
>I know what it stands for Jerry. It was a joke.
>
>And actually it stands for Collection, Holding and Transfer tank.
And I forgot to add this. Smell was not a problem because the tanks
were always cleaned and disinfected before I ever got into them. This
was not true at most of the WWTPs I worked at later. I watched this
Indian guy take off his shoes, socks and pants and wade knee deep on a
strut in the top of a aeration tank once at a small private plant. He
asked me to wash him down with a garden hose afterwards.
| |
| Jerry Avins 2006-11-22, 3:25 am |
| Paul M wrote:
> On Tue, 21 Nov 2006 19:03:39 -0500, Jerry Avins <jya@ieee.org>
> proclaimed to the world:
>
>
> I know what it stands for Jerry. It was a joke.
>
> And actually it stands for Collection, Holding and Transfer tank.
It's the straight-faced ones that always take me in. I should know
better. When I do it, people often get put off, not amused.
Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
| |
| Paul M 2006-11-22, 3:25 am |
| On Tue, 21 Nov 2006 22:32:57 -0500, Jerry Avins <jya@ieee.org>
proclaimed to the world:
>Paul M wrote:
>
>It's the straight-faced ones that always take me in. I should know
>better. When I do it, people often get put off, not amused.
>
>Jerry
I'm not put off at all. I find you refreshingly simple in your logic
and insistence of accuracy. That IS a compliment, BTW. You can be the
straight man in my act! :-)
| |
| daestrom 2006-11-23, 9:25 am |
|
"Paul M" <PaulMatWiredogdotcom> wrote in message
news:fm07m29i8pb2gt9s1piqua1b5290hg6edc@4ax.com...
> On Tue, 21 Nov 2006 21:11:30 GMT, "daestrom"
> <daestrom@NO_SPAM_HEREtwcny.rr.com> proclaimed to the world:
>
>
> I never even got to see any of those subs except along the docks at
> the sub piers sitting near the old diesels. I guess they were built to
> last without much repair. ;-)
>
> And those luxury liners were not so luxurious when ripped apart in dry
> dock, particularly since I was there to work on storage tank level
> indicator/controls. They would never tell me what "CHT" stood for. It
> must be classified. (LOL) I figured it must be "Chocolate Heaven Tank"
> from the looks of what was left in the tank when we got to it. To tell
> the truth, I also worked on a lot of other stuff too.
On the older boats, we didn't mess around with such 'euphenisms'. They were
called 'sanitary tanks', but were far from 'sanitary'. (why *is* it that
sewers for human waste are called 'sanitary', seems a complete perversion of
the term :-)
daestrom
| |
| Trevor Jones 2006-11-23, 5:25 pm |
| daestrom wrote:
> (why *is*
> it that sewers for human waste are called 'sanitary', seems a complete
> perversion of the term :-)
>
> daestrom
>
Because it was more sanitary than chucking it onto the street from a
second story window?
Cheers
Trevor Jones
| |
| Bruce Durdle 2006-11-29, 3:25 am |
| The Ministry of Truth strikes again ...
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:rYi9h.29086$xw1.25903@twister.nyroc.rr.com...
>
> "Paul M" <PaulMatWiredogdotcom> wrote in message
> news:fm07m29i8pb2gt9s1piqua1b5290hg6edc@4ax.com...
>
> On the older boats, we didn't mess around with such 'euphenisms'. They
> were called 'sanitary tanks', but were far from 'sanitary'. (why *is* it
> that sewers for human waste are called 'sanitary', seems a complete
> perversion of the term :-)
>
> daestrom
>
|
|
|
|
|