RANCANG BANGUN ELEKTRONIK MOTOR RELAY UNTUK PROTEKSI GANGGUAN OVER LOAD, PHASE LOSS, PHASE REVERSE, PHASE UNBALANCE, SHORT CIRCUIT, LOCKED ROTOR DAN GROUND FAULT

System of protection for trouble at induction motor has a critical role in the industry. In common, the protection of electric motor installation using only the fuse and MCB (Miniature Circuit Breaker). Protection by fuses and MCB only able to overcome short circuit and over current fault, in addition, there are still many other problems that can not be protected. The purpose of this final project is to plan and create an electronic motor relay for over load, phase loss, phase reverse, phase unbalance, short circuit, ground fault, and locked rotor. AVR microcontroller is used as the controller of all the systems in detecting the disorder. Where the range of flow settings and trip time is programmed using C language which is operated with the keypad and display to the LCD. As the current and voltage sensing using a current transformer and voltage transformer which was followed by an electronic circuit. For phase reverse sensing, takes the signal from deferensial amplifier forwarded to zerro crossing, triger and compared in X-Or. While the ground fault sensing using a zero current transformer. Accuracy testing of electronic relays motor performed in each trouble type. From these data showed that a microcontroller can be used as a precision analog voltage controller. That is because the AVR microcontroller has good features and supported processor speed is adequate for use in such applications. Key word : protection, fault, induction motor