Title:
RUSH CURRENT LIMITING METHOD
Document Type and Number:
Japanese Patent JP3760552
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To suppress the rush current at power recovery to a small value so as to protect a circuit element, by calculating the time from power stoppage till the voltage recovery between the terminals of a smoothing capacitor dropped by a specified voltage drop value each time of power stoppage, and turning on the rush current limiting resistance before the computed time elapses.
SOLUTION: CPU 8 monitors the existence of the voltage of an AC power source at all times at the same time with the start through a photoisolator 6, and when it receives the information of power break, it operates the time to turn on a rush current limiting resistor 3. In this case, this operates the time, taking the voltage drop value of the specified smoothing capacitor 4 and the delay of the detection of the power stoppage of an AC power source into consideration. Next, the CPU 8 turns off a contact 91 by operating a driving circuit at the point of time when this time has passed, and turns on the rush current limiting resistor 3. Hereby, this can prevent the breakdown of the circuit element by preventing the rush current from becoming excessive without being delayed even in case of the power stoppage for an extremely short time.
Inventors:
Kazuo Sato
Application Number:
JP7749197A
Publication Date:
March 29, 2006
Filing Date:
March 28, 1997
Export Citation:
Assignee:
Yaskawa Electric Co., Ltd.
International Classes:
H02H3/24; H02H9/02; H02H3/247; H02J1/00; H02J9/06; H02M7/06; (IPC1-7): H02H9/02; H02H3/24; H02H3/247; H02J1/00; H02J9/06; H02M7/06
Domestic Patent References:
| JP7107664A | ||||
| JP59201636A |
Attorney, Agent or Firm:
Nobuyuki Kaneda
Katsuhiro Ito
Ishibashi Masayuki
Katsuhiro Ito
Ishibashi Masayuki