Fault detection apparatus for rotor winding of rotary machine

A fault detection apparatus for a rotor winding of a rotary machine comprising;

• a magnetic flux sensor mounted in proximity to a surface of a rotor having said rotor winding wound thereon, said rotor being mounted in a stator of said rotary machine while leaning an air gap therebetween, said magnetic flux sensor sensing a leakage flux of said rotor winding in each slot of said rotor,
• a peak value hold circuit for detecting peak values of a pulsing waveform of the signal supplied from said magnetic flux sensor, holding said peak values for a predetermined time period and then resetting the held value,
• a register for storing past peak values,
• a peak value processor for comparing the peak value held in said peak value hold circuit with the corresponding one of the peak values stored in said register, and
• a monitor for indicating a fault in said rotor winding,
• said processor determining the presence or absence of the fault in said rotor winding based on a result of the comparison of the corresponding peak values and applying a signal indicative of the fault to said monitor when the fault is determined.