| 摘要 |
PCT No. PCT/AU84/00198 Sec. 371 Date Jun. 5, 1985 Sec. 102(e) Date Jun. 5, 1985 PCT Filed Oct. 11, 1984 PCT Pub. No. WO85/01773 PCT Pub. Date Apr. 25, 1985.A monitoring circuit for a door operating D.C. electric motor, the circuit comprises a first means for detecting a back EMF of the motor and producing a load signal indicative of the magnitude of the back EMF, a second means for detecting the time rate of change of the load signal and issuing an obstruction signal if the magnitude of the time rate of change of the load signal exceeds a predetermined value. |
