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I found a Vybo electric motor and noticed that it has seven connectors for power cables. I also found a Variable Speed Drive, Altivar Process ATV900, System ATV960, 800/630 kW, 400 V and its datasheet lists many characteristics out of which I mention:

  • Motor power: 800 kW,

  • Continuous output current: 1420 A at 2.5 kHz,

  • Line current: 1335 A at 400 V,

  • Motor recommended cable cross section: 6 x (3 x 185 mm²) or 5 x (3 x 240 mm²).

Question: Should I understand that the Vybo motor in question needs 6 three phase cables, each of them with 3 conductors of 185 mm² in cross section, or 5 cables with three conductors of 240 mm², each; independently of the fact that the motor is powered from the VSD or directedly from the 400 V, 50 Hz industrial source?

enter image description here Fig. 1. ELECTRIC MOTOR 800KW H17RL-450-4, 1488RPM, 380V-400V-420V, Low Voltage.

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  • $\begingroup$ Do you think those 7 things are connectors? Or could they be cable glands with the actual connectors inside? And 7 to allow for control and sensing cables as well as power cables? $\endgroup$
    – Solar Mike
    Commented Aug 1, 2022 at 7:18
  • $\begingroup$ It does sound like each of the 3 internal coils are controlled fully separately with a high current connector, plus a protective earth. $\endgroup$ Commented Aug 1, 2022 at 8:18
  • $\begingroup$ @SolarMike , They are cable glands. However, according to this guide (see: sghcable.com/pdf/cable_usage/App-2E%20V2.pdf) a 3-ph AC cable can carry min 245 A/ phase. So, six 3-ph AC cables in parallel (with all 6 phases a ( and b, c) connected together at ends) carry 245 A x 6 = 1470 A/phase. Now, if we go back to the 800 kW motor and calculate its line currents in ideal conditions, we get: I = 800kW/(400V*sqrt(3))= 1154 Amp, so the 6 AC cables mentioned above are well suited to power this motor. This is an explanation found by my for the 7 glands of the motor but I might be wrong. $\endgroup$ Commented Aug 1, 2022 at 14:39

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