Υπολογισμός ισχύος κινητήρων

Motor calculation for various applications.
 
1. Pump motor.
Pump motors are calculated using the following equation.

	/ 3600
P =		W
γ =		N/m3
Q =		m3/h
h =		m
n =

where :
γ stands for the fluid specific weight in  Ν/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
η 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

	x 9.81
P =		W
G =		kp
v =		m/s
n =

where :
G is the maximum load to be lifted in  kp (1kp = 9.81N).
v is  the elevation velocity in  m/s.
η 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

	x 27.7777
P =		W
Q =		m3/h
Dp =		bar
n =

where :
Q is the air flow in  m3/h.
Dp is pressure raise in  bar =10⁵  Pa (N/m2).
η is the motor - fan (or compressor)  system total efficiency factor  (0.50 ~ 0.70).