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Current Locus 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.

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  • \$\begingroup\$ Show the example as an embedded picture and please differentiate whether it is a motor or a generator. \$\endgroup\$
    – Andy aka
    Jul 10, 2019 at 14:17
  • \$\begingroup\$ Picture added, machine is a motor (also added) \$\endgroup\$
    – TobiK
    Jul 10, 2019 at 16:09

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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: -

enter image description here

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  • \$\begingroup\$ 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. \$\endgroup\$
    – TobiK
    Jul 10, 2019 at 18:42
  • \$\begingroup\$ Look up phaser diagrams and see how they align with the rotated graph. Downwards in negative imaginary impedance. \$\endgroup\$
    – Andy aka
    Jul 10, 2019 at 22:01

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