| 摘要 |
1354490 Control of A.C. motors ELECTRIC ACTUATOR CO Ltd 20 July 1971 [24 July 1970] 35979/70 Heading H2J [Also in Division F2] An A.C. induction motor driving the push-pull rod of an actuator operating a valve (see Division F2) is stopped or reversed by a control circuit which directly detects an increase in the electrical load of the motor consequent upon the arrest of the rod at the end of its working stroke. The circuit shown employs the coil CT1 to sense the stator current of the motor and the relay RE1 to control the power supply of the motor. A typical operation of the circuit is described, including actuation of a manual switch S1 when the motor is started after being stopped, whereby operation of the circuit is prevented during the period of the initial starting surge of current to the motor. |
