| 摘要 |
<p>PURPOSE:To decrease a decoupling time of an electromagnetic coupling device, by inverting supply voltage to an excitation coil for a very short time immediately before decoupling and removing residual magnetism after decoupling. CONSTITUTION:At decoupling of an electromagnetic coupling device 10, command signals S2, S3 are led out from a control circuit 18 to actuate switching elements 12, 13. Here electromotive force, stored in a coil 15, is absorbed by a varister 16. If this electromotive force becomes lower than power of a DC power source, a reverse excitation current of the electromagnetic coupling device 10 flows from a side of the DC power source to a side of the earth through the switching element 13, coil 15 and switching element 12. That is, in a route for the reverse excitation current to flow, a resistance element is not connected except the coil 15, and power of the DC power source is fully applied to the coil 15, then electromotive force at coupling is absorbed by the varister 16. Accorddingly, the reverse directional excitation current rises earlier.</p> |
