# Induction Motor: Reason why the current locus is on the positive imaginary axis The shown locus is of an induction motor. I was wondering if there is a reason why the imaginary current of a current locus of an induction machine is positive. Every equation contains a term like $$\-j U_s / X_s \$$ (for example if there is no load).

Normally, all current locus are printed with a negative imaginary axis. In a book I found examples with a positive imaginary current.

Is it just a different way of displaying it or does it impact how the Motor behaves?

Edit: The locus shows the stator currents to a maximum slip of around 0.3. Therefore the locus is no half or complete circle. Also: 5 different frequency-locuses are shown.

• Show the example as an embedded picture and please differentiate whether it is a motor or a generator. – Andy aka Jul 10 '19 at 14:17
• Picture added, machine is a motor (also added) – TobiK Jul 10 '19 at 16:09

## 1 Answer

Here you go; if the image is rotated placing the real values on the horizontal axis as is normally the case with (say) phasor diagrams you get the imaginery axis being negative: - • Actually, the most diagrams look almost exactly like the one I posted before with the only difference that the imaginary axis (still facing the right hand side) is negative... Right now I assume that it is just aother way of displaying the locus but I cannot find any proof for my assumption. – TobiK Jul 10 '19 at 18:42
• Look up phaser diagrams and see how they align with the rotated graph. Downwards in negative imaginary impedance. – Andy aka Jul 10 '19 at 22:01