Drive arrangement with variable speed induction motor - incorporates switching units and temperature sensor for stator windings temperature

摘要

The variable speed drive system uses an induction motor. Step-by-step changes in motor speed are provided by a simple switching system. Pole changing switching or frequency switch (or changing) of the supply vottage is used, and a temperature sensor is provided to sense the stator windings temperature. - The switch-over point (or points) during pole changing, or frequency changing of the supply voltage is determined by the output magnitude of the temperature sensor. At least one switch-over point is specif. selected so that balanced torque exists between the two torque-revs. characteristics.