1 horsepower = 746 watts

charlie_potatoes

I'm hung like a horse
HTH

wishitwasallflat

I eat like a horse

florerider

My kettle is 4 hp, isn't that useful to know.

DesB3rd

Yep, it's a heavy horse drawing load on a gadient - hence the work can be measure based upon the load raised over a given distance in a given time.

It's an overestimate and by some margin, Watt was terrified by the prospect of litigation.

rayjay

Horse's come in different sizes. You have the Massive horse or the tiny micro stallion.

I mean , what I'm saying , you get the idea. How can the micro stallion have the same power output as the Massive horse?

Would a donkey that is bigger than a smaller horse have more power.

I have gone past a donkey before.

ai_1

rayjay wrote:

Horse's come in different sizes. You have the Massive horse or the tiny micro stallion.

I mean , what I'm saying , you get the idea. How can the micro stallion have the same power output as the Massive horse?

Would a donkey that is bigger than a smaller horse have more power.

I have gone past a donkey before.

1hp is not the power of each horse. As mentioned elsewhere on the thread, it's a unit of power measurement based very broadly on the useful power a typical horse could continuously generate and is equal to about 746W.

hatch87

The other thing to remember is watts is the same as mph, its measured over an hour. When you cycle for an hour your max speed is kind of irrelevant as its what distance you done in that hour. 20 miles covered and you done 20mph, or in an hour, 300w avg is 0.3kWh's.

I would assume hp is the same, so you need to produce 746w for an hour to be more powerful than a horse, easy peasy

ai_1

hatch87 wrote:

The other thing to remember is watts is the same as mph, its measured over an hour. When you cycle for an hour your max speed is kind of irrelevant as its what distance you done in that hour. 20 miles covered and you done 20mph, or in an hour, 300w avg is 0.3kWh's.

I would assume hp is the same, so you need to produce 746w for an hour to be more powerful than a horse, easy peasy

This is either incorrect or I'm misunderstanding you.

A watt is a watt. It's a measure of power which is the rate of doing work. You don't have to maintain it for any specific period of time for it to be real.
A watt-hour (Wh) is not the same as a watt (W). A watt-hour is a measure of energy or in other words a measure of power expended over time. So it takes the same amount of energy to generate 500W of power for 1 hour (500Wh) as it does to generate 50W for 10 hours (500Wh). The energy used will still be 500Wh if the power level fluctuates all over the place during any period of time so long as the average power in watts multiplied by the time in hours equals 500Wh.

I think it's very confusing to equate the relationship between power and energy to that between speed and distance but if you were to do so, power would equate to speed and energy would equate to distance. Still I think this is best ignored as it's just an over-complication.

hatch87

Easiest way to explain it is using a light bulb. When you switch on a 100w light bulb, it doesn't instantly use 100w's, that is the amount of energy/power it will consume over an hour.

Everything is based over a given distance, whether that is time or distance, 50mpg doesn't mean anything until you've used up a gallon of fuel

ai_1

hatch87 wrote:

Easiest way to explain it is using a light bulb. When you switch on a 100w light bulb, it doesn't instantly use 100w's, that is the amount of energy/power it will consume over an hour.

Everything is based over a given distance, whether that is time or distance, 50mpg doesn't mean anything until you've used up a gallon of fuel

No! - This is completely incorrect.

You are attempting to discuss power and energy interchangeably. This is incorrect and what you are saying is not accurate.

If a light bulb is running on 240V and draws 0.417A thats 100W. Time or distance have absolutely nothing to do with it.

If your bulb runs at 100W for 1hour then you've used 100Wh of energy. This is a different measurement, energy not power and has different units Wh not W.

hatch87

Turns out there is a few different versions of a watt, changing between jouels (1 watt is one meter per second) and and current flow or electromagnetism (measurement of amperes)

So the argument changes to what does 1 hp mean in terms of watts. If 1 hp is 33,000 foot-pounds of work every minute, its velocity per second requires a maths head I do not have

markhewitt1978

A watt is actually a shorthand for joules per second. Energy in all of it's forms is measured in joules, that could be in the form of electricity, heat, motion and energy can only be transformed not destroyed - GCSE physics..

If a lightbulb is 60W this simply means that it 'uses' 60 joules of energy every second - but it doesn't have to be even a second of usage, this is just what it would be if it had been used for a second. e.g. it could run for half a second and use 30 joules but still be 60W

So watts is a measurement of the power output at that precise momemt, with no time dependency at all.

kWh etc is really just a simplied way of measuring energy use, techincally it should be in joules, or kJ, MJ etc.

ai_1

hatch87 wrote:

Turns out there is a few different versions of a watt, changing between jouels (1 watt is one meter per second) and and current flow or electromagnetism (measurement of amperes)

So the argument changes to what does 1 hp mean in terms of watts. If 1 hp is 33,000 foot-pounds of work every minute, its velocity per second requires a maths head I do not have

A watt is a watt.
It's a standard unit of measurement and is unambiguous. There is only one version.

1 watt = 1 joule per second = 1kgm2/s3

hatch87

hatch87 wrote:

Turns out there is a few different versions of a watt, changing between jouels (1 watt is one meter per second) and and current flow or electromagnetism (measurement of amperes)

So the argument changes to what does 1 hp mean in terms of watts. If 1 hp is 33,000 foot-pounds of work every minute, its velocity per second requires a maths head I do not have

Kind of proves I'm right, just poorly worded

1 horsepower (over the course of an hour) is equivalent to 2,545 BTU (British thermal units). If you took that 746 watts and ran it through an electric heater for an hour, it would produce 2,545 BTU (where a BTU is the amount of energy needed to raise the temperature of 1 pound of water 1 degree F).
One BTU is equal to 1,055 joules

bompington

So let me get this right, if I crash my car into a brick wall at 80mph it will be much worse if I've been cruising at a steady 80 for an hour than if I've only being doing that speed for a few seconds?

hatch87

bompington wrote:

So let me get this right, if I crash my car into a brick wall at 80mph it will be much worse if I've been cruising at a steady 80 for an hour than if I've only being doing that speed for a few seconds?

Well yea, just think of all that fuel you wasted.

But for a serious answer, the crash would be measured in G force and the speed could be measured in mach so its per second rather than hour

markhewitt1978

bompington wrote:

So let me get this right, if I crash my car into a brick wall at 80mph it will be much worse if I've been cruising at a steady 80 for an hour than if I've only being doing that speed for a few seconds?

Assuming the same starting conditions and a mineral oil fuelled car (not electric) then you will have used 1 hours more fuel in the first situation so the crash will be slightly less severe. Your chances of survival will not be significantly changed!

ai_1

hatch87 wrote:

hatch87 wrote:

Turns out there is a few different versions of a watt, changing between jouels (1 watt is one meter per second) and and current flow or electromagnetism (measurement of amperes)

So the argument changes to what does 1 hp mean in terms of watts. If 1 hp is 33,000 foot-pounds of work every minute, its velocity per second requires a maths head I do not have

Kind of proves I'm right, just poorly worded

1 horsepower (over the course of an hour) is equivalent to 2,545 BTU (British thermal units). If you took that 746 watts and ran it through an electric heater for an hour, it would produce 2,545 BTU (where a BTU is the amount of energy needed to raise the temperature of 1 pound of water 1 degree F).
One BTU is equal to 1,055 joules

hatch87,

No, it doesn't prove you're right. Your last few posts have been entirely misinformation and confusion.
I'm not sure what point you were originally trying to make but your understanding of the terms are variously confused, ambiguous and plain wrong. There's nothing wrong with making a mistake but continuing to push it and potentially confuse others is unhelpful.

hatch87

I did confirm I was wrong, I got my Watts mixed up, although I was right that it is measure over time. Its just 1 second rather than an hour

However, what my previous post did prove is that the 746 watts that a horse produced was calculated by working out how much energy it produced over the course of an hour. So for a cyclist to produce 1 hp it needs to be done under the same conditions. Essentially produce 2,545 BTU which is done by producing an average 746w for an hour

ai_1

hatch87 wrote:

bompington wrote:

.....But for a serious answer, the crash would be measured in G force and the speed could be measured in mach so its per second rather than hour

Now you're making me pedantic:
There's no such thing as "G force".
Acceleration is measured in m/s^2 and sometimes in multiples of "g" the acceleration due to gravity at sea level which is approximately 9.81m/s^2.
Mach number is not a unit of speed. It's a dimensionless ratio comparing speed through a body of fluid to the local speed of sound in that fluid. The whole point is to convey the impact of compressibility effects for the purposes of aerodynamic analysis. It has no use in this case where airspeed of the car ad the wall is irrelevant.

I hope you're trolling because you're ability to misundertand units of measure is becoming quite impressive. It's like you found a list of terms and you're just adding them to sentences at random.

ai_1

hatch87 wrote:

I did confirm I was wrong, I got my Watts mixed up, although I was right that it is measure over time. Its just 1 second rather than an hour

However, what my previous post did prove is that the 746 watts that a horse produced was calculated by working out how much energy it produced over the course of an hour. So for a cyclist to produce 1 hp it needs to be done under the same conditions. Essentially produce 2,545 BTU which is done by producing an average 746w for an hour

All nonsense.
You still don't know what you're talking about and have failed to read, or understand the corrections already provided.
Your copy and paste regarding BTUs etc is just a brief explanation of the conversion between HP and BTU. It's completely irrelevant to the conversation. You've pasted it in, misinterpreted it and drawn conclusions that it does not contain.

Try re-reading markhewitt's explanation a few posts back.

markhewitt1978

I said that watts are number of joules used per second. But the unit of time is irrelevant. A lightbulb running at 60W is running at 60W if it's for 1 second, 1 hour, or a nano-second.

hatch87

No such thing as G force? I can't argue with that, but generally in motor racing an accident is measured in G so find it hard to believe no such thing exists.

However, my 746w's over an hour is equivalent to 1 hp still stands

Edit

markhewitt1978 wrote:

I said that watts are number of joules used per second. But the unit of time is irrelevant. A lightbulb running at 60W is running at 60W if it's for 1 second, 1 hour, or a nano-second.

but 60w's is equivalent to traveling 60 meters per second with 1n of opposite force.

Daz555

I'd still like to know the peak power of a horse.

As I mentioned earlier a racehorse can run 200m in under 10 seconds. For such a large animal to get moving so quickly must take some serious power.

A wiki article suggest a horse is capable of a peak power of almost 15hp. So that is over 11,000W if we take the 1hp=746W rule.

ai_1

hatch87 wrote:

No such thing as G force? I can't argue with that, but generally in motor racing an accident is measured in G so find it hard to believe no such thing exists.

Acceleration can be measured in "g" (small g) which is acceleration under gravity at sea level as per my previous post. It's not a force and it's not a capital G. These details are essential if you want to have this conversation.
Motor racing commentary is not an ideal source of information for physics/engineering terminology.

hatch87 wrote:

However, my 746w's over an hour is equivalent to 1 hp still stands

It stands wrong: the "hour" has no place in that sentence. The duration doesn't matter.

By the way it's W not w (it matters)

Daz555

hatch87 wrote:

However, what my previous post did prove is that the 746 watts that a horse produced was calculated by working out how much energy it produced over the course of an hour. So for a cyclist to produce 1 hp it needs to be done under the same conditions. Essentially produce 2,545 BTU which is done by producing an average 746w for an hour

We need to move past this hour stuff.

Also James Watt did not calculate the work done by a horse over an hour to come up with the HP rating. He actually examined out the work done by a pony per minute over a 4hr period and then added 50%.

"Watt determined that a pony could lift an average 220 lbf (0.98 kN) 100 ft (30 m) per minute over a four-hour working shift. Watt then judged a horse was 50% more powerful than a pony and thus arrived at the 33,000 ft·lbf/min figure."

hatch87

But how is it wrong? if we start fresh forget everything either one of us said.

1 horse power (over the course of an hour) is equivalent to 2,545 BTU (British thermal units).
746W (over the course of an hour) is equivalent to 2,545 BTU (British thermal units).

That is the test/equation that was done to establish that 1 hp is the same as 746W. The 746W isn't a horse's peak power at full tilt, its what it produces over the course of an hour

http://auto.howstuffworks.com/horsepower.htm

1 horsepower is equivalent to 746 watts. So if you took a 1-horsepower horse and put it on a treadmill, it could operate a generator producing a continuous 746 watts.

I'll have to leave it there as I'm going home now

ai_1

Daz555 wrote:

I'd still like to know the peak power of a horse.

As I mentioned earlier a racehorse can run 200m in under 10 seconds. For such a large animal to get moving so quickly must take some serious power.

A wiki article suggest a horse is capable of a peak power of almost 15hp. So that is over 11,000W if we take the 1hp=746W rule.

Sounds like a feasible ballpark figure to me.
Think of it in terms of 1pp (person power). What would you reckon 1pp might be in watts? Maybe in the region of 100W?
What can a really good sprinting cyclist manage? 2000W?

So if the same multiple applies to horses then a good race horse might hit 20hp or 746x20= 14.9kW.

But that's just a speculation - it's probably the right order of magnitude but I wouldn't read more into it than that.

rayjay

Ai_1 wrote:

rayjay wrote:

Horse's come in different sizes. You have the Massive horse or the tiny micro stallion.

I mean , what I'm saying , you get the idea. How can the micro stallion have the same power output as the Massive horse?

Would a donkey that is bigger than a smaller horse have more power.

I have gone past a donkey before.

1hp is not the power of each horse. As mentioned elsewhere on the thread, it's a unit of power measurement based very broadly on the useful power a typical horse could continuously generate and is equal to about 746W.

What's the wattage of a micro stallion then?

How many donkeys watts would it take to blow a Marshall 4 x 12 cab ...i.e. would you have to turn it up to 11/ and how do you turn a donkey up to 11? what about 12 or is that right out?

Would it make sense to stick some horses on a wind turbine ,,,,,say in Demark for instance?

What woodland creature produces the most power output ,,,i'd guess at a large squirrel.

charlie_potatoes

Charlie Potatoes wrote:

I'm hung like a horse
HTH

I can confirm this to be true.

Regards
Mrs. Potatoes