MALFUNCTION DETECTION CIRCUIT OF EXCITER IN BRUSHLESS EXCITATION SYSTEM

PURPOSE:To continuously detect the malfunction of a brushless exciter in the all operating states of a synchronous machine by comparing a field current calculated value calculated from the output of the machine with the detected value of the actual exciter field current. CONSTITUTION:An exciter malfunction detector 42 calculates an exciter field current Ifca necessary to generate the present generator output from a reactive power. If a defect occurs in the winding of a rotary rectifier 26 or an armature 28 in the rotor 30 of an exciter 12, an automatic voltage regulator 36 operates to strengthen the field of the exciter 12. Accordingly, the actual exciting current Ife detected by a current transformer 38 is increased from that at normal time. The detector 42 detects the malfunction of the exciter 12 by the fact that the state of Ife>Ifca continues for the prescribed time or longer.