A detector for detecting of phases asymmetries in the case of a three-phase - rotary machine and device for the protection of the machine operating conditions, which is an gefa

摘要

A detector for detecting phase-asymmetry in connection with a three-phase rotary machine includes a sensor couplable to the machine for picking up a signal associated with the leakage field during rotation of the machine. Circuit means are also provided for amplifying characteristic components of the signal (i.e., components whose amplitudes greatly increase relative to other components when phase-asymmetry occurs) and for attenuating other components of the signal, particularly at frequencies around f and 3f where f is the line frequency. Converter means converts the output of the circuit means into a control voltage, and control means are responsive to increases in the control voltage above a predetermined level established in the absense of phase-asymmetry for producing an output signal indicative of phase-asymmetry.