Flame-proof AC squirrel-cage motor - has first winding for second flame-proof class and additional winding to comply with third class

摘要

The flame-proof a.c. squirrel-cage motor has a winding (1) with a specified number of conductors in the stator to comply with the (G2) flame-proof classification, and an additional winding (2) with a different number of conductors connected in to comply with the (G3) flame-proof classification. Both windings are insulated so that they fall into a higher insulation class than is necessary for flame-proof machines. By suitably choosing the ratio between the numbers of conductors in the two windings, similar values for the torque and for current during starting and short circuit can be obtained.