a) Calculate the operating speed of the fan at steady-state.
b) Compute the motor phase current when the motor is started
A 25 kW, 3-Phase 6-Pole 50 Hz squirrel cage induction motor has the following equivalent-circuit parameters in Ω per phase:
• R1 = 0.12
• R2 = 0.15
• X1 = 0.79
• X2 = 0.76
• Xm = 26.2
The motor is connected to a fan which presents a load proportional to the cube of the rotational speed, given as:
Pfan = 23 (RPM/1000)^3 kW
The motor is initially at rest and is started by connecting the terminals to a 3-Phase, 50 Hz 400V line-line source.