The goal of the present paper is to design and build electronic protection unit for detection of failures in alternator of diesel generator because of the many technical problems and failures or abnormal operating conditions that accompany the work of the generators when it used as a substitute for electrical energy, especially in long working hours.
Some of these problems and failures: increasing the temperature of the stator coils, loss of excitation, over/under frequency, over/under voltage and phase failure.
When any problem occur the proposal protection unit will be displayed the type of error or problem on liquid crystal display (LCD) as well as gives us an audio alarm and also shuts down the generator in critical situations.
The design was adopted mainly on microcontroller PIC16F877A, this design is characterized by low cost, uncomplicated, very high response and flexible to change software in case you need to add another failures without changing hardware if compared with the current protection unit in the original generators.