| Summary: | 碩士 === 國立勤益科技大學 === 電子工程系 === 103 === With an increasing development of electric-driven facility applications, traditional mechanical or No Fuse Breaker (NFB) is unable to meet the safety protection in industry. This may result in a fire occasionally. The main problem is that currently the fastest breaker can react only in 01 sec. For example, the electric breaker produced by SHIHLIN ELECTRIC company needs 0.15 sec to operate. For the 3A fast fuse, its reaction time takes about 1 sec. As above, no commercial breakers can efficiently protect fragile equipments at the moment. Therefore, the development of fast and current-adjustable electric breaker is a crucial research topic. This research is to design a fast and current-adjustable electric breaker that can be directly applied to AC-driven facilities. It mainly contains four parts: (a) Current sensing circuit: Hall effect sensor is used to detect the current amount and be converted into a voltage signal. (b) Voltage amplifier and comparator circuit: The voltage signal received from Hall effect sensor is amplified and connected with the comparator to check if the load current is over the limit. (c)Timer circuit: Based on IC 555 timer, the trigger signal can be generated once the current is beyond the predefined value. Then, the output of timer circuit can provide a trigger signal for a certain period of time. (d) Opened-path control circuit: The optical-isolated transistor and TRIAC are used to open the AC power if the trigger signal is received. From the experimental results, it has verified that the proposed electric breaker can react within 10ms that is much faster than traditional ones. Accordingly, it has achieved the high standard for industrial applications.
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