METHOD OF PROTECTING SYNCHRONOUS AC MOTOR AGAINST WINDING SHORT CIRCUITS Russian patent published in 2019 - IPC H02H7/08 

FIELD: electric power engineering.

SUBSTANCE: use: in the field of electric power industry to protect a synchronous AC motor against winding short circuits in the stator and rotor windings. Method is based on measuring the difference in the parameters of the frontal-scattering magnetic field at several points in the end zone. From the absolute value of the difference of the measured parameters allocate harmonic components with frequencies of 2f_cn and 2f_cn/p, and if the component with a frequency of 2f_cn exceeds the first threshold, signals are formed about the presence of coil circuit in the stator winding, and if the component with a frequency of 2f_cn/p exceeds the second threshold, signal is formed about the presence of a coil circuit in the rotor winding, where n is an arbitrary value that can take the values 1, 2, 3…; p is the number of poles, and f_c – frequency of the main harmonic network.

EFFECT: technical result is to prevent damage from vibration and, as a result, to reduce the time and cost of the post-breakdown repair of a synchronous electric machine when the turns in the rotor winding close.

1 cl, 3 dwg