| 摘要 |
PURPOSE:To attain ease of maintenance and to make the cost inexpensive by providing a relay unit having an oscillator to an intermediate point of a series switch of a gate turn-off thyristor so as to decrease the length of an optical fiber and make the oscillator in common use. CONSTITUTION:The relay unit 44 is provided to a point having an intermediate potential of a gate turn-off thyristor GTO, and an optical signal transmitted from an ON-signal light emitting element 23 and an OFF-signal light emitting element 28 of a control panel 20 of ground potential via optical fibers 45, 46 is converted into electric signals by photodetectors 47, 48. The ON-signal is transmitted to units 11-24 by a light emitting element 51 and an optical fiber 52 via an oscillator 31 and inputted to a gate circuit 53. The OFF-signal is transmitted to the units 11-14 as it is via a light emitting element 54 and an optical fiber 55. Thus, the length of the optical fiber is reduced, the cost-down is attained by using the oscillator in common to each unit, the maintenance is made easy and the reliability is improved. |
