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My brain hurts -- belt drive problem - Wild Turkey - 03-06-2017

1725 rpm motor drives 2" pulley which belt drives a 6" pulley which shaft drives a 1-1/2" pulley which belt drives a 6" pulley.

What is the final speed of the shaft driven by the 6" pulley?
Confused
Confused
Confused

Iv'e come up with from 46 to 143 rpm.
Rolleyes


RE: My brain hurts -- belt drive problem - HomerLee - 03-06-2017

I'd say 143.75


RE: My brain hurts -- belt drive problem - Wild Turkey - 03-06-2017

(03-06-2017, 05:33 PM)HomerLee Wrote: I'd say 143.75

Seems slower than that.
Confused

Maybe I can dig out old tachometer and get a reading.

EDIT to add: Tach (OOOLDD direct drive ) wouldn't read but quick manual count leads me to think 143 is accurate.

Need to find way to cut speed down some more.


RE: My brain hurts -- belt drive problem - Stwood_ - 03-06-2017

Scroll down a tad and use the calculator.


http://www.culvermotor.com/Engineering-Formulas/Pulley-and-RPM-Calculator.html


RE: My brain hurts -- belt drive problem - blackhat - 03-06-2017

Switching to 8" pulleys instead of 6's would get you to 81 rpm on your wheel.  An 8" on the jackshaft and a 9" on the wheel shaft would get you to 72 rpm on the wheel.


RE: My brain hurts -- belt drive problem - TDKPE - 03-06-2017

(03-06-2017, 05:33 PM)HomerLee Wrote: I'd say 143.75

(03-06-2017, 05:55 PM)Wild Turkey Wrote: Seems slower than that.
Confused

Maybe I can dig out old tachometer and get a reading.

EDIT to add:  Tach (OOOLDD direct drive ) wouldn't read but quick manual count leads me to think 143 is accurate.

Need to find way to cut speed down some more.

143.75 is correct (multiply the two ratios together, then multiply by the driver speed for the driven speed), and it's a shade over 2 rotations per second.  That's pretty slow looking.


RE: My brain hurts -- belt drive problem - Downwindtracker2 - 03-06-2017

I know the feeling. I'm changing the motor and sheaves on my 14" bandsaw. It took three tries to get my SFM. Those gears haven't seen grease for a long time .This getting old thing.


RE: My brain hurts -- belt drive problem - daddo - 03-07-2017

Larger pulleys are less wearing on belts due to flexing and require less tension depending on angle of contact. Increasing the smaller pulleys size helps with this. Probably not that important, just thought I'd mention it.