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- Homework Statement
- 4. A four-pole, star-connected, squirrel-cage induction motor operates from

a variable voltage 50 Hz three-phase supply. The following results were

obtained as the supply voltage was gradually reduced with the motor

running on no-load.

Stator line voltage 220 164 112 88 42

Stator line current (amperes) 6.8 5.4 3.9 3.8 3.7

Stator power (watts) 470 360 278 244 232

(a) By plotting a suitable graph from these results, determine the total of

windage and friction losses, the no load magnetising current I0

(assume no load current I0 is magnetising losses) and the equivalent

circuit magnetising circuit parameters R0 and X0.

- Relevant Equations
- P = √3 x VL x IL x CosФ

So I've attached my graph and found that the windage/friction losses occur roughly around 230Watts. I just don't know how i further explain the magnetising current I0. I know I0 = input current on no load. So do i assumed from

**P = √3 x VL x IL x CosФ**that CosФ=230/√3*220*6.8= 0.0849 or 85.1degrees (220 and 6.8 is what i assume voltage and current are on load). I0=IL*CosФ = 6.8/0.08 = 0.577Amps**.**Just wish to see if I am going right so far otherwise my R0 and X0 will be wrong.