help with pulleys

[shooter]

I’m stuck, I can’t formulate a search string to get me where I want to be 
I got this far (image).  The left bottom pully is the driven 2 “ rated 1750RPM 5HP
I got the RPM’s down to 70 but I’m clueless on what the HP did, if anything.
 
Thanks
dave

[PRR]

The HorsePower ideally stays exactly the same.

In practice every 10:1 of gearing will suck-off 5% to 50% of power as friction. High-ratio gearing is lossy and/or real costly. Yes, past 10:1 you may prefer 2-stage, as you have done to get 20:1. (Also to avoid 12-foot wheel and 45-foot belt.)

Car gears may be well-made and can be found cheaper than new. Two first-gear transmissions and a rear-axle run close to 70:1. There was even a production lawn-tractor which ran a belt to a box to a cut-down 1950 Plymouth axle.

[shooter]

Thanks, was guessing it stayed the same but one of the hemisphere's wasn't havin it! 
so 5HP minus losses it is!
working toward substituting an electric motor driven water pump with a 4 stroke.  I don't have the electric pump yet, planning stage!

[PRR]

> substituting an electric motor driven water pump with a 4 stroke.

Engine?

A 5 horse utility engine is liable to be rated at 3600RPM. At 1800RPM it may be under 3 horses. Engines driving slow grunt-loads may need a lot of step-down. In fact historically this was part of the rush to Diesel-Electric drive on railroads. "Gearing down" with motor connections is less lossy than most gear systems.

[shooter]

the engine is 8hp, currently on my snow thrower but it's a problem child, has been for 5yrs now.  the water pump is driven by either a 1/4HP or 1/2HP electric, need to visit Lowes for conformation.  It's an irrigation type, not a 30' well pumper so load should be minimum.
I do have a 2:1 gear head that I used for a elevator to haul 4X8 sheets up 2 stories when I did the barn roof.


Step-down is what keep hanging me on what HP did in my example.  I know there is a force multiplier when stepping down, just not
what force.
i'm still paying off the laundry room remodel so it's be a couple months before I can put pieces together for testing to see what snags the real world has

[kagliostro]

I know there is a force multiplier when stepping down, just not what force.

Look here



if you use an rpm reductor (pulley or gear the difference stay on different friction) what you will obtain will be to move your load in a slower way, but then you will be able to move a higher load

ideally (if you leave friction from compute) if you use a 10:1 rpm reductor, you'll obtain to moltiply for 10 times the load, but at a 10 times lower speed (power stay always the same)


Franco

[shooter]

thanks Franco, torque was the part I was getting hung up on.


if I freeze the water and slide it over ice the horse will be happy 

[kagliostro]

if I freeze the water and slide it over ice the horse will be happy