Motor calculation for various applications.
1. Pump motor.
Pump motors are calculated using the following equation.
where :
stands for the fluid specific weight in /m3 (9810N/m3 for water and 8000 for petroleum).
Q stands for pump flow capacity in m3/h.
h is the discharge height in m
is the motor - pump system total efficiency factor (0.50 ~ 0.70).
2. Lifts , elevators and cranes.
Motors for these applications are calculated using the following equation
where :
G is the maximum load to be lifted in kp (1kp = 9.81N).
v is the elevation velocity in m/s.
is the motor - pulley system total efficiency factor (0.50 ~ 0.70).
When calculating person lifts G we must add 75kg (=kp) for each person.
If there is a contraweight we must divide the work load by 2.
For a 10 person lift with a contraweight , the load for the equation is
10 x 75kp = 750kp / 2 = 375kp
3. Fan - compressor motors.
Motors for these applications are calculated using the following equation
where :
Q is the air flow in m3/h.
Dp is pressure raise in bar =10^{5} Pa (N/m2).
is the motor - fan (or compressor) system total efficiency factor (0.50 ~ 0.70).