how to figure conveyor rpm's 1

[crosstown]

hi guys. im new to conveyor repair and new to this forum. i need a little help. i've got a speed reducer with an input/output rpm ratio of 37.5/1 my output pulley is 8 inch dia increasing to a 12 inch dia on my head spool. the driver is a 3775 rpm ac motor. what are my rpm's on the 12 inch & what's a good rule of thumb to figure this problem out next time? Thankee much

 

[Ross0684]

From your details:
Input speed 3775 rpm
ratio 37.5:1
Output speed of reducer 3775/37.5=100.6667 rpm.

I assume that you have an 8" pulley on speed reducer driving a 12" pulley on conveyor drive pulley(spool)
Speed of Conveyor drive pulley(spool)=(100.6667 X 8)/12=67.11 rpm

Check the forum list as this was not the best forum to raise this issue(see materials handling equipment engineering!!)

Ross