| 摘要 |
<p>Known switching devices have a commutator connected in parallel to a switching section and a condenser for both driving the switch and turning-off the power semiconductor of the commutator. The disadvantage of these devices consists in that they are not able to supply the required turning-off energy in all cases. According to the invention, firing pulses for switching and bridging valves in the switching branch are triggered at the same time as a switching command for the quick make-and-break, so that the current is switched when the contact starts to open into the switching branch and only later, when the switching section of the quick make-and-break is already open and there is no more any risk of short-circuiting the turning-off condenser, a turning-off thyristor is fired and the switching thyristor is turned-off by discharging the turning-off condenser, cutting the switching current. In order to monitor the switching section, the corresponding valves in the switching branch are fired, establishing a current flow between the busbar and the switching section, and the current, whose intensity represents a criterion for the state of the section, is measured at the exit of the section. Various circuit arrangements are disclosed to carry out the process.</p> |
