In this paper a microcontroller based experimental unit for parallel connection of alternators for education purposes has been designed and implemented. This experimental set designed detects the incorrect phase order firstly, which is one of the conditions of parallel connection, and corrects it automatically. The other three conditions of parallel connection, the equality of voltages, frequencies and phase angles of two alternators are then obtained by the experimental set. All these measurements are processed numerically by 16F877 microprocessor and the parallel connection is achieved automatically. As a consequence, students can see the faults of parallel connection which occurred during the application in the laboratory studies. Since all the processes of parallel connection of two alternators are visualised, students can find solutions for the faults and prevent them. In addition, this experimental unit developed can be used as an alarm circuit for industrial purposes at the conditions of phase disconnections.