Torque or winding squirrel cage motor - has rotor with parallel groups of high conductivity rods with varying resistance PTCs

摘要

The motor generates a speed from zero up to the synchronous value. The armature has two or more parallel groups of highly conducting rods (10, 11) with different resistance positive temperature coefficients. The coefficients are so related to each other, that in continuous operation at speeds from zero to synchronous speed the total conductivity is about constant. Preferably the rods are made of materials with melting point above 1000 deg.C and specific conductivity ranging from 10 to 20 gm/sq. mm. Thus one group may be of iron with specific conductivity of 105m/sq. mm, and another one of a copper-nickle alloy with specific conductivity of approximately 20 gm/sq. mm.