Pulley size, RPM, HP calculator??

[mike90045]

Thanks Tom. Yes, please keep the suggestions coming and I'll update it in a couple days and likely put it on my website with the other calculators.  ..... 

Looked at your member info, did not find the website ?   Calculator is slick, thanks.

[sailawayrb]

Glad you like it Mike.  By popular request I have been creating/hosting several flavors of calculators on my hydronic floor heating website:

http://www.borstengineeringconstruction.com/Calculators.html

I'll eventually put this one there plus a couple other ones that some affiliates have requested.

Bob B.

[tinkerer]

Bob, thanks for going through the work to create your calculator.
Ben

[mobile_bob]

Bob

did you include service factors in your calculations?

from memory the engineering from browning among others have factors for single cylinder engines, generators, hours use per day
and maybe others...

iirc the service factor is on the order of 1.4 for single cylinder diesel engine's and as much for generators in welder duty for instance.

then there is plain belt vs notched belt factors,

i tried to get your calculator to work, but my puter won't run it for some reason, maybe its just me.

fwiw
bob g

[Frank S]

Bob g I had the same problems Bob B and I msg back and forth until I was flustrated as a last ditch I let it download to the bottom of my browser then RT clicked save as but I added ".html" without the quotes to hte end of the actual file name then hit save the file remained in my download bar when I clicked on it it opened right up perfectly .

[sailawayrb]

Hi Bob G.

No, I elected not to embed service factors directly into the code.  However, service factoring can be accomplished if desired by factoring the HP input.  The calculator is really only accurate for flat and vee belts.  It would provide conservative results for grooved and notched belts.  I wanted to make the calculator adaptable to the user, which is why I didn't embed the friction coefficient or groove angle directly into the code either.  Frank suggested that I consider having the calculator provide belt type recommendations (i.e., A, B, C, etc.) based on the calculated belt speed and tension values.  If I can locate some good representative data, I would be happy to do that.  Mainly, I just wanted to try to assist Ben with his problem solving.  With some of the problems folks have reported about downloading and getting it to work, I reckon I should be more motivated to just get it on my website.

Bob B.

[tinkerer]

Bob, I downloaded your calculator and put in my numbers. I'm not really sure what alot of those numbers are or mean. If you wouldn't mind, I'll give you my proposed pulley sizes and RPM, HP ect and see what you think. Will it work or not?? 

HP-12
input RPM-2800rpm
Desired output RPM-approx 1850
input pulley diam-5.31 "this is what the machinest that will be machining my pulleys says" I'd like to check his work and make sure...The driven pulley will be 8"
pulley shaft center to center distance-24 inches This is a rough guess. It could be a little shorter.
angle of pulley groove- I'm not sure what to use for this. I'm using an 8 rib serpentine belt

Tell me what you think.
Thanks!
Ben

[sailawayrb]

Ben, looks like your numbers work.  Calculator says the output pulley should be 8.04 to get your 1850 RPM.  Belt speed will be 3892 FPM and tension ratio is 2.8 and therefore under the recommended 3.0 for flat belts.  Required inital belt tension should be about 131 lbs (so as to not slip if you used just a flat belt...you can likely go less with the ribbed belt) which would result in a dynamic bearing load of about 212 lbs.  Output shaft torque will be about 34.1 ft-lbs.

Bob B.

[tinkerer]

Good to hear that it should work!  Thanks Bob for your input and time!

[Frank S]

Bob g I had the same problems Bob B and I msg back and forth until I was flustrated as a last ditch I let it download to the bottom of my browser then RT clicked save as but I added ".html" without the quotes to hte end of the actual file name then hit save the file remained in my download bar when I clicked on it it opened right up perfectly .

If someone has problems getting it to work on their computers and the above doesn't do the trick Just Rt click the link before downloading select save link as when the menu opens on the name add ,html hit save then it will d/n load and open right up.
I didn't think I would use it all that much but this morning my guys have already used it several times
Really great tool thanks Bob b

[Henry W]

Bob B,

I like your calculators.

I think I will be using it soon. Thanks for posting them.

Henry

[sailawayrb]

Well, I am humbled and honored that you like this calculator so much.  For those who had trouble (or who may have trouble in the future) downloading the version that I posted on this thread, I placed this calculator on my website today:

http://www.borstengineeringconstruction.com/Calculators.html

I still consider this calculator a "beta" version and I will likely test/update it as time/energy permits.  Again, feedback and improvement suggestions are certainly welcome.

Bob B.

[mobile_bob]

Bob

if you would like please also post a link in the "white paper" section of our forum

perhaps just a short index of those calculators you have developed, with a link to your site
so that folks can skip over there as needed.

thanks so much for your effort and sharing the results

bob g

[sailawayrb]

Thanks Bob G...done 

Bob B.

[coronan]

I used the calculator.  I want to run a 5hp pump with a 2 hp motor.   I'm not sure the belt will handle it, or if i need 2 belts.   If i use a Idler pulley to increase contact angle, can I get away with one belt?

I'm looking at a 3.5" ish drive wheel and a 11" ish pump pulley.   What is the load on the belt?

In the calculator: does HP refer to the motor or the load?