PURPOSE: To obtain a method and a device which can easily diagnose the degree of deterioration of an electric circuit for accurately predicting the failure timing of the electric circuit and a method and a device for detecting an abnormal waveform which are suitable for them.
CONSTITUTION: A threshold voltage setting circuit 203 sets two threshold voltages Va and Vb between the maximum and minimum levels of the output of a right arm RA of an inverter in an uninterruptible power supply device. A comparator 206 compares the number of times when the output level of the right arm RA passes the threshold value voltage Va with a reference count. A comparator 207 compares the number of times when the output level of the right arm Ra passes the threshold voltage Va with the number of times when it passes the threshold voltage Vb. Comparator 214 and 215 compare the time width and the reference time width when the output level of the right arm RA passes between threshold values. The outputs of the comparators 206, 207, 214, and 215 are taken out as abnormal waveform detection outputs and are counted by a counter 217.
Tsukio Mukai
Masumi Obata
Umewaka Masaharu
Nippon Battery Co., Ltd.
| JPH0335170A | 1991-02-15 | |||
| JPS63100380A | 1988-05-02 | |||
| JPS62145173A | 1987-06-29 | |||
| JPS6381265U | 1988-05-28 | |||
| JPH0226342U | 1990-02-21 | |||
| JPH0226821U | 1990-02-21 |
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