| 摘要 |
1,108,216. Control of A.C. motors; protective arrangements. BORG-WARNER CORPORATION. 19 July, 1966 [30 Sept., 1965], No. 32441/66. Headings H2J and H2K. A three-phase motor 15, which drives a submersible pump in an oil well, is protected both against overload and underload, the underload control being initially disabled for a short period to allow the motor to start. When the current in one of the supply-lines 18-20 increases above a set value, any one of the meters 34-36 responds to energize timedelay relay TR1. After a period, relays R1, R2 are de-energized to disconnect the motor 15 from its source. The motor cannot be restarted until a push-button 10 is actuated. Except during the starting period when delay contacts CTR2b are closed, the meters 34-36 also respond to an undercurrent or phase unbalance condition to de-energize relay R2 and stop the motor. Once the motor has been stopped, other than after an overload, it can be re-started either manually by operating push-button 75, or automatically by timer 76, according to the position of selector switch 64. |
