Patent ID: 9722530
Date: 2017-08-01
CPC Classifications: F25B,F25D,H02P

Claim:
1. A drive circuit for an electric motor, comprising: a driving source unit, configured to generate a driving source signal; a driving unit, connected to the motor and configured to drive the motor according to the driving source signal; a sensing unit, configured to sense an actual rotational speed of the motor; a control unit, connected to the sensing unit to receive the actual rotational speed and configured to cause the motor to stop operating by causing the driving unit to stop driving the motor when the actual rotational speed falls below a predetermined rotational speed; and a timing unit, connected to the control unit and configured to start timing a predetermined time period when the control unit causes the motor to stop operating, an additional sensing unit configured to cause the control unit to keep cutting off a transmission of the driving source signal from the driving source unit to the driving unit; a protecting unit, connected to the additional sensing unit and the control unit, and wherein the protecting unit causes the control unit to stop the transmission of the driving source signal from the driving source unit to the driving unit when the actual rotational speed falls below the predetermined rotational speed, and causes the control unit to resume the transmission when the predetermined time period expires.