FIELD: protection of a three-phase power equipment against asymmetry of currents, current ground leakage and affection of man by electric current.
SUBSTANCE: the method of protection consists in estimation of instantaneous values of asymmetry of phase currents in the load, comparison of these values with the tolerance and disconnection of the load from the source of the three-phase power mains in case the value of asymmetry of currents in the load is out of the tolerance. The device has a magnetic starter and a load, in addition it has a relay for estimation of the degree of asymmetry of phase currents in the load, whose inputs are in-phase connected to the outputs of the magnetic starter, and the outputs - to the load inputs, and the relay break contacts are series-connected to the magnetic starter winding.
EFFECT: enhanced reliability and equipment duplication.
1 cl, 3 dwg
