| 摘要 |
PURPOSE:To prevent a damping resistance from thermal destruction, by such means that with a current in DC motor of each group detected and its unbalance factor obtained, at the time of this unbalance reaching a prescribed value, the breaker be operated. CONSTITUTION:At the time of brake operation, contactors B1 to B4 are short circuited with contactors P1 to P4 released. Consequently, for instance, with respect to DC motor of a first group, a closed circuit will be constructed such as contactor B1- damping resistor R1-chopper CH1-contactor B2-field coil F1-current detector DCCT1 -armature M1-smoothing reactor MSL-high speed breaker HB1- contactor B1, and also with respect to DC motor in a second group, the same closed circuit be constructed as in the above. If the chopper CH1 makes a commutation failure, for a signal of DCCT1,DCCT2 inputted to a break command circuit 21, when exceeding a tolerable unbalance pattern, high speed breakers HB1, HB2 will be made open. |
