Title:
OVERVOLTAGE PROTECTING DEVICE OF OPTICALLY FIRING THYRISTOR
Document Type and Number:
Japanese Patent JPS5911772
Kind Code:
A
Abstract:
PURPOSE:To prevent the damage of a voltage suppression element by connecting the voltage suppression element and a detector which detects the forward voltage in parallel with an optical firing thyristor, thereby protecting the firing thyristor against an overvoltage or monitoring the number of elements, to which the forward voltage is applied. CONSTITUTION:Voltage suppression elements 54-57 are connected in parallel with optical firing thyristors 50-53, and light emitting elements 66-69 which generate time signals, to which the forward voltage is applied, are further connected. The output of an operational amplifier 86 for adding the voltage signals becomes a value proportional to the number of the firing thyristors, to which the voltage is forwardly applied. When the forward voltage is applied to the optically firing thyristors less than 50, the output of an AND circuit becomes ''1'', a signal is applied to a firing signal generator 22, a transistor 25 is operated, light emitting elements 27-30 emits lights, and firing signals are fed to the thyristors 50-53. Accordingly, all thyristors 50-53 are fired, thereby eliminating the voltages at the elements 54-57.
Inventors:
MATSUMURA SUSUMU
YANO MASAO
SASHIDA NOBUO
YAMAMOTO YOSHIHIKO
YANO MASAO
SASHIDA NOBUO
YAMAMOTO YOSHIHIKO
Application Number:
JP12083582A
Publication Date:
January 21, 1984
Filing Date:
July 12, 1982
Export Citation:
Assignee:
KANSAI ELECTRIC POWER CO
MITSUBISHI ELECTRIC CORP
MITSUBISHI ELECTRIC CORP
International Classes:
H02H7/12; H02H7/122; H02M1/00; H02M1/092; H03K17/082; H03K17/72; H03K17/79; (IPC1-7): H02M1/18
Domestic Patent References:
| JPS4953385A | 1974-05-23 | |||
| JPS5553176A | 1980-04-18 |
Attorney, Agent or Firm:
Masuo Oiwa