st-bum wrote:
> What's the relationship between torque and HP? I never understood
> that.
>
> And I had a year of physics at an engineering shchool.
>
> I know power is work and torque is twisting force (F * r), but somehow
> I would think the two would be very similar.

http://www.geocities.com/CapeCanaver...679/motor.html

 

Learning Richard wrote:
> st-bum wrote:
> > What's the relationship between torque and HP? I never understood
> > that.
> >
> > And I had a year of physics at an engineering shchool.
> >
> > I know power is work and torque is twisting force (F * r), but somehow
> > I would think the two would be very similar.
>
> http://www.geocities.com/CapeCanaver...679/motor.html

wow that page is from 1997 too

 

"Andrew Stephenson" <ames@deltrak.demon.co.uk> wrote in message
news:1131853325snz@deltrak.demon.co.uk...
> Thanks for the insights on the USian setup. However, our local
> power company here in the eastern UK did install such power line
> decorations to save swans/geese/etc from accidents, when flying
> around favoured grazing/landing sites. Maybe they saved the odd
> plane too -- dunno.
>
Yes - here in the States the ***** are orange, and are mandated by FAA
regulations where lines cross open expanses that helicopters might want to
cross. Interestingly, birds won't go near high tension lines (although they
sometimes build nests on 69KV poles). The "induction" apparently bothers
them as much as it bothers us. Lower voltages don't seem to affect birds
much.

Interesting to use windmills for piecework production. They are poorly
suited for public grids because they are too intermittent. Some think any
windy spot is suitable, but the requirements are daunting. The site must
have reasonably predictable winds mostly around the rated speed (presently
about 12 m/s or around 25 mph). Since the power output changes with the cube
of the wind speed, dropping the wind speed from 12 m/s to 10 m/s means a 40%
drop in output - a real budget breaker when you are contracted to deliver so
many MW. Here in the States many wind farms too often operate at a loss
because of failure-to-deliver penalties, and proposed FERC rules relating to
power hygiene (such as phase regulation... wind farms have been bad
neighbors on the grids so far) could make that worse. But for producing
hydrogen they could theoretically be made to pay off.

Mike

 

"st-bum" <kennykabuki@yahoo.com> wrote
> What's the relationship between torque and HP? I never understood
> that.
>
> And I had a year of physics at an engineering shchool.

Re-read the chapters of the text on work, power, and torque.

> I know power is work

No. Power is work delivered per unit time.

> and torque is twisting force

> (F * r), but somehow
> I would think the two would be very similar.

Google for explanations that will probably be better than any given off the
top of one's head here or at any personal web site.
http://www.straightdope.com/mailbag/mhorsepower.html isn't bad.

--
Honda home studies: http://home.earthlink.net/~honda.lioness
--

 

On 2005-11-13, Michael Pardee <michaeltnull@cybertrails.com> wrote:

> neighbors on the grids so far) could make that worse. But for producing
> hydrogen they could theoretically be made to pay off.

bingo!

 

"notbob" <notbob@nothome.com> wrote in message
news:3Pidnd0OqJeE-ereRVn-uA@comcast.com...
> On 2005-11-13, Michael Pardee <michaeltnull@cybertrails.com> wrote:
>
>> neighbors on the grids so far) could make that worse. But for producing
>> hydrogen they could theoretically be made to pay off.
>
> bingo!

Hey, they gotta be good for something! :-) I have a brother who used to
work for American Wind Power in California, but I don't think they are in
business any more.

Seriously, uses that don't care much about the unpredictable nature of wind
power are a lot more attractive than going live on the public grids. Even
pumping water for gravity storage makes sense where the water and land are
suitable. Land that has the required characteristics for real-time wind
power is amazingly scarce and can become expensive if demand increases. Land
that has a usable amount of wind enough of the time for production
enterprises is far more common.

Whether hydrogen generation is going to have enough demand for wind or solar
powered cracking to be practical remains to be seen, but I don't rule it
out.

Mike

 

Thanks for that straightdope line. I knew power was work/time, just
misspoke.

That's the best explanation I've heard.

 

In article <1131860509.264966.282990@g49g2000cwa.googlegroups .com>
kennykabuki@yahoo.com "st-bum" writes:

> What's the relationship between torque and HP? I never
> understood that. [...]

At the risk of repeating what others and have said and what you
know already...

Torque is, basically, a rotational (ie, twisting) force.

HP (horsepower) is a rate of doing work, so can also be expressed
in units such as watts (the modern preference, 1 HP == 746 watts)
and BTU (if one must).

An easy way to remember the equivalence between Force, Distance
(over which the Force is used) and Work (another way of saying
Energy) is to recall that
Work = Force * Distance

So Power, the Rate Of Doing Work, is
Work / Time

Therefore the Work done by Torque is, in effect, the Force acting
at a certain Leverage distance, tracing a circular path around a
point, over a certain Time.

One final relationship:
Torque = Force * Leverage
where Leverage is the distance between the line-of-action of the
Force and the pivot point, about which the Torque is calculated.

A 15 kilo Force pushing on a lever 2 metres long exerts a Torque
at the pivot point of 15*2 kilo-force-metres (not to be confused
with kilometres). Most engineers use Newtons, not kilos-force:
Newton = Kilo * 9.81 (approx)

So that Torque would actually be (about) 294.3 Newton-metres.

Back to the original question...

Work done in 1 revolution
= 2 * pi * Leverage * Force
= 2 * pi * Torque

So rate of doing work (ie, Power)
= 2 * pi * Torque / Time_for_1_rev
= 2 * pi * Torque * Revs_per_second
= watts

Use Newton-metres here and it is a doddle to compute Power. If
you absolutely must know the HP, divide Watts by 746.

(FWIW, AFAIK: 1 Pound-force-foot == 1.355818 Newton-metres. And
for pi you can get by with 3.14159, though it goes on to many <g>
more significant digits than that.)

Grief, I hope I got that lot right. <g> If anyone knows better,
do let me know soon.
--
Andrew Stephenson

 

"Mike Hunter" <mikehunt2@mailcity.com> wrote in message
news:iAidnbfkG7CdC-veUSdV9g@ptd.net...
> Camry may still be the number one selling car but it was never the number
> one vehicle sold in the US. The F150 is the number one seller and has
been
> for nearly thirty years, at just about twice as many sold as the Camry.
> Camry is aparently not as popular as it was last year either. Cold it be
> becse they are underpowered? The Camry was the ONLY vehicle in the top
five
> to lose sales in 2005, it dropped around 20,000 sales, falling from third
> place to fourth below the Dodge Ram. The others all gained sales,
including
> the Honda Accord, which is actully made in the US, not merely assembed of
> imported parts like the Camry
>
> VEHICLE Sales Y-T-D 2005 Last Yr. '04 Rank Chg.
>
> 1 Ford F-Series pickup 760,929 740,817 1 +2.7
> 2 Chevrolet Silverado pickup 616,139 575,886 2 +7.0
> 3 Dodge Ram pickup 409,252 362,122 6 +13.0
> 4 Toyota Camry 383,478 403,136 3 -4.9
> 5 Honda Accord 371,307 367,210 5 +1.1
>
>

Having exactly what to do with your repeated unsupported allegation that
Toyotas are underpowered?

Still, with every pickup, you get highway mileage in the teens! Yippee!
And, in spite of its voracious appetite for gas, Edmunds had this to say
about the F150:
http://www.edmunds.com/new/2005/ford...chlanding.html
"Feels sluggish even with larger V8."

Gee, thirsty AND slow. Who would have expected THAT from a Ford?

Get some facts and a clue and get back to us.

>
> "dh" <dh@stargate.com> wrote in message >
>
> > The Camry is one of the most popular cars on the market. Toyota
actually
> > makes money selling them. Most people think the 4 is at least
adequately
> > powered or they wouldn't buy them and Toyota wouldn't make money selling
> > them. Friends who drive them think they move out just fine (and none of
> > these owns one of the latest with VVTi and a better power-to-weight
ratio
> > than ever before).
> >

 

Considering the same vehicle weight and gearing, the vehicle with the higher
HP will go faster. Considering the same vehicle weight and HP the vehicle
that develops its torque at lower RPMs will be more powerful. Torque is
what enables a vehicle to get going from a stop more quickly and keeps it
going under load.

mike hunt


"st-bum" <kennykabuki@yahoo.com> wrote in message
news:1131908790.615823.230240@o13g2000cwo.googlegr oups.com...
> Thanks for that straightdope line. I knew power was work/time, just
> misspoke.
>
> That's the best explanation I've heard.
>

 

Thank you very much for your informative reply.

 

On Sun, 13 Nov 2005 03:42:05 GMT, ames@deltrak.demon.co.uk (Andrew
Stephenson) wrote:

>In article <he4cn15ikkbsvihp0rlbom29lkc3ausdlc@4ax.com>
> blPYTHONbergman@earthlink.invalid "Bruce L. Bergman" writes:
>
>> On Sat, 12 Nov 2005 02:33:08 GMT, ames@deltrak.demon.co.uk (Andrew
>> Stephenson) wrote:
>>
>> >One parallel is not exact but close: power lines commonly snag
>> >birds as they fly past. That's why you will see silvery *****
>> >strung on the lines, especially at valley mouths where flyways
>> >lead up into (and down from) hill country. Here in the UK the
>> >power company have cut local swan deaths by this precaution.
>>
>> Sorry, but no. That's not the primary reason why the visibility
>> ***** are placed, or they would be installed on all power lines.
>>
>> [discussion of the US situation]
>
>Thanks for the insights on the USian setup. However, our local
>power company here in the eastern UK did install such power line
>decorations to save swans/geese/etc from accidents, when flying
>around favoured grazing/landing sites. Maybe they saved the odd
>plane too -- dunno.

Sorry, they're for light aircraft in the UK too.

Documents and reports should be available at your local HSE office, go
n and ask nicely. They should be able to find you the mountains of
reports on it.

>
>Back to the windmills: perhaps I ought to enquire as to rates of
>bird strike locally, now that more and more of the whirly things
>are being installed. Mind, some are offshore, by a mile or two,
>and I am guessing we can spare the odd seagull (breeding to pest
>numbers).

 

st-bum wrote:
> What's the relationship between torque and HP? I never understood
> that.
>
> And I had a year of physics at an engineering shchool.
>
> I know power is work and torque is twisting force (F * r), but somehow
> I would think the two would be very similar.
>

Torque X rotational speed = Power. To get the units right in various
systems, a conversion factor is used.

A very good discussion is available on the web at:

http://www.straightdope.com/mailbag/mhorsepower.html

Power is the ability to do work. Work is needed to move a mass from one
place to another, to increase elevation, to increase velocity
(acceleration) and to overcome frictional losses like air resistance,
tire rolling resitance, etc.

Thus, for example, 200 ft. lbs. of torque at 4,000 RPM can accomplish
twice as much work as can 200 ft. lbs. of torque at 2,000 RPM. Put
another way, 400 ft. lbs. at 1,000 RPM can do the same work as does 200
ft. lbs at 2,000 RPM. For the units used in the US:

Power (HP) = [Engine Speed (RPM) x Engine Torque (ft.lbs.)] / 5252

It is really that simple.

John

 

> "Mike Hunter" <mikehunt2@mailcity.com> wrote in message

>>VEHICLE Sales Y-T-D 2005 Last Yr. '04 Rank Chg.
>>
>>1 Ford F-Series pickup 760,929 740,817 1 +2.7
>> 2 Chevrolet Silverado pickup 616,139 575,886 2 +7.0
>> 3 Dodge Ram pickup 409,252 362,122 6 +13.0
>> 4 Toyota Camry 383,478 403,136 3 -4.9
>> 5 Honda Accord 371,307 367,210 5 +1.1


2006 is certain to take away a lot of the thunder from Mr. Hunter's
argument. Large truck and SUV sales are dropping like a rock while
sedan and small crossover SUV sales are increasing.

Somewhere in the next couple of years Toyota is going to pass GM in
worldwide sales volume and will never look back. If the Delphi
bankructcy results in supply distruptions to GM, which is highly likely,
then 2006 will be the year of the changing of leadership for sure.

Years ago GM unseated Ford and has never looked back. GM did it with a
better product range and agressive salesmanship. Unfortunately Detroit
has had it's eye off the ball for too many years now.

John

 

Michael Pardee wrote:
> But for producing
> hydrogen they could theoretically be made to pay off.
>
> Mike
>
>

An excellent point you make sir! Wind power to add to energy storage,
be that storage hydrogen or some form of battery, makes lots of sense.
It is much harder to make wind generators put out the constant voltage,
constant phase output the grid wants to see.

John