Originally Posted by sganesh

.....The drive pulley RPM is 102 when the conveyor is empty and 90 RPM when the hopper is loaded.

Is the variation of the RPM is normal? Because it affects the feed rate.

Regards,

S.Ganesh

What you are really saying is that the feed rate is affecting the rpm. This is quite normal in the drive mentioned. ■

I would say that the motor has excessive leakage and is slipping.

Take off the motor case drain hose and run the motor and put it in a bucket. If the flow out of the case is heavy then replace or have the motor overhauled. 1 to 2% leakage is common. So if you know the flow rate to the motor you know how much leakage you should have. ■

Gary is quite right about case drain build up: but also consider that in order to provide constant motor speed under varying torque requirements you must have a variable pressure pump. Such pumps are expensive because they are often variable stroke units as well.

Refer to your pump characteristic curves for some insight. If the motor is behaving in accordance with the pump curve delivery then the motor is OK and the pump possibly is as well. ■

It's normal in induction motor, and is abnormal in synchronous motor ■

Originally Posted by dinglu

It's normal in induction motor, and is abnormal in synchronous motor

==========================================================

Dinglu- these are hydraulic motors not electric motors

leonZ ■