Dual speed rotary vane pump

摘要

A dual speed mechanical rotary vacuum pump wherein a mechanical rotary vacuum pump is directly connected to a two speed electrical motor which drives the pump and the speed of the motor is controlled by an electrical control circuit which selectively causes the motor to rotate at either a first speed for a predetermined period of time or at a second slower speed. The speed of the motor is automatically switched to the slower speed after the predetermined period of time.