A company called the other day with a question about their conveyor. My company did not build the conveyor but did supply the gearbox. The conveyor is 8 feet long, and 4 feet wide, it is level and transports castings to the grinding department of a foundry. The motor they are using is a 4 pole 5HP motor, assuming at 60Hz. I was told the castings get "dumped" onto this conveyor which is always turning, so there is a bit of a shock load. The foundry wants to be able to move 3000lbs of castings on this conveyor, however when they put the load on the conveyor the motor trips out. The gearbox that is on their conveyor is rated for 9000in-lbs with a 5HP motor and 29 rpm. The conveyor shaft is 11 inches in diameter and coupled directly to the output shaft of the gearbox. I used an equation that I found but had to convert the values to metric and then back to standard. The force is MU * Mass* Gravity, where MU is 0.5, the 3000lbs is converted to Newtons:13344.66 Newtons, gravity is 9.81 So F=0.5*13344.66*9.81 Force = 65455.6Newtons Torque = 65455.6N * 0.2794m : the 0.2794 is the 11 inch shaft converted to meters Torque = 18288.3Nm; 161865.2in-lbs Am I on the right path with this? If so the current gearbox is greatly undersized. Thanks for the help it is greatly appreciated.