mech 153 - Assignment 4

question 1

A 1200 rpm motor drives, by means of a spur gear and pinion, a machine rated at 7.5 kW and operating under moderate shock, 8 hours a day.  The reduction in rpm is 3:1.  Select a suitable pair of 20° pressure angle spur gears to tranmit the power required.

question 2

A machine that works under smooth operating conditions is used twice a day for about 10 minutes.  Currently, It is manually operated and rated at to running at 800 rpm.  Two motors are in stock at the plant that might be able to be used to automate this machine.  One motor is rated at 7 hp and 1200 rpm.  The other is rated at 5 hp and 750 rpm.  Spur gears are to be used with a 20° pressure angle.  Report on the selection of both motor and gears to make this system work.