Applications of statistical techniques to the quality improvement of a 15A circuit breaker

As an initial step to implement total quality management (TQM) in a small manufacturing enterprise (SME) of electrical products, we applied statistical techniques to quantify and evaluate the date collected in order to improve the quality characteristics of a selected product circuit breaker. A circuit breaker will ‘jump’ or the current will be cut short if a current stronger than 15A passes through the equipment. The time required for the circuit breaker to stop the flow of the current is called the trip-time. Our major concern is to find out how sensitive a 15A circuit breaker is, and how reliable is the device. We were able to confirm several dominant factors that influence the trip-time of the circuit breaker after conducting several experiments. We used regression analysis to find out the model that best fits the relationship between the current supply and the trip-time of the 15A circuit breaker. Meanwhile reliability testings of the circuit breaker were performed. Balanced factorial design techniques were applied in finding out the optimal combination of factors with the highest success rate of trips. The results demonstrated that the optimal combination of factors we found could bring about quality improvement of the product.