device for synchronous motors with massive poles to protect polklorna against forbrenningar

摘要

A synchronous motor incorporates a rotor structure having solid poles. In order to improve the starting characteristic of the motor and protect the pole claws against burning, conductive bars are arranged at each side of the pole below the pole shoe and are electrically connected with the pole to form a quadrature-winding which provides a conductive path for currents induced at the pole surfaces by the time-variable quadrature-field and causes such currents to close around the quadrature-field thereby eliminating current from pole-to-pole by way of the claws. The quadrature-winding also forms a circuit parallel to the solid pole surfaces which thereby improves the asynchronous torque characteristics at low slip rates and reduces the oscillating torque.