Magnetising circuit parameters in a 3ph induction motor

[justadaftspark]

Homework Statement

Homework Equations

The Attempt at a Solution

Stator Line voltage 220 164 112 88 42
Stator Line Current 6.8 5.4 3.9 3.8 3.7
Stator power 470 360 278 244 232

By plotting a suitable graph from these results, determine the total of windage and friction losses, the no load magnetising current Io (assume no load current Io is magnetising losses) and the equivalent circuit magnetising circuit parameters Ro and Xo.

I have plotted the graph and estimated that the losses for friction and windage is 220w. I am unsure as to how to calculate the magnetising current and therefore the values of Ro and Xo.


I(ph) =I(line)/ROOT3 = 3.93A
Vph =V(line)/ROOT3 = 127.02v
Pph = P(line)/ROOT3 = 127.02w
cos THETA = P/V*I = 75.5deg, Lag
Ro = V/IcosTHETA =129.09Ohm
Xo = V/IsinTHETA = 33.38Ohm

Or do I replace the power value with Total losses-friction and winding losses which equals 250w

Any help in the right direction would be ace.

 

[rob1985]

Hi justadaftspark, how did you work out the friction and windage losses. the lessons don't show me the equation.