Wuzzat?

On a machine I can put out a half hp for one minute and much less power for many minutes.
One hp is supposed to be what a horse can put out all day.

What can they put out for one minute? Has anyone seen a graph for this?

I've seen them pull a wagonload of people up a mild hill for two minutes or so, so the hp expended could be calculated but this experiment is not easily set up where I live.

nealtw

http://www.web-cars.com/math/horsepower.html

Wuzzat?

Yeah, that's the all-day avg. pwr.

My all-day avg. pwr input is maybe 2000 Calories over 16 hours, 120 Cals/hr, 140w, 0.2 hp, so if my body is 20% efficient I can put out 30w all day long.
And I have put out 1 hp for 30 seconds.

How much force can a horse exert in the short term, for how long over what distance, before they start breathing very hard?
5 hp, maybe, using a block and tackle to match the horse's force with the load to be moved?
Anybody have examples of this?

nealtw

You would have to use the same horse that Watt used and then you don't know that that horse couldn't have worked harder all day. It was just an obsevation. You would have to consider age, weight, condition, shoes and the surface he will walk on and what he had for breakfast.
If a half horse motor uses 8 amps, are all motors that use 8 amps 1/2 horse?
If a motor use 12 amps on start up is it a 3/4 horse?
So call your self Watt assistant and make some reasonable guesses.

Austin

Interesting I didn't know that about horsepower. I always assumed it would take that many horses to pull that car that fast.

Kidding, but I had no clue how it was decided.

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nealtw

It os funny how stories change, I found that site but in school I learned that Watt was looking at horses working in coal mines. I don't think Wuzzat will find his chart, I guess he could look at the racing ponies and the difference between a long and short race. Someone must have looked at it to come up with the distance between Pony Express station. But then you have to look at the weight or size of the horse.

Wuzzat?

With proper gearing/belts, yes, at least in principle.

The avg. US house takes a kw on avg. continuously so a horse on a treadmill could do this for a while. Add an enormous flywheel and he/she might be able to handle peak loads.

nealtw

http://www.horsepull.com/sport%20of%20horsepulling.htm

Austin

So you're saying I need a horse?

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Wuzzat?

Well, figure the cost of oats, maintenance, etc., and then tell the PoCo goodbye. Or not. . ..