7. Conclusion

How well an induction motor performs in service depends largely on how well the constraints it will have to cope with have been analyzed and taken into account. Two factors, not completely independent of each other, are particularly important: torque and starting current:

• Firstly, the motor torque must be greater than the resistive torque at all times and, in particular, during start-up; this may require the use of special cage constructions (deep-notched cages or double cages) or the use of wound-rotor motors with inserted resistors;

• As for the starting current, which can vary from 6 to more than 10 times the rated current, it must not cause voltage drops that disturb neighboring installations or reduce the starting torque too much.

As these voltage...