What is Relay Lack of Phase?

They are relays lacking in phases and act in the control systems in the protection of motors against the harmful effects of phase and / or neutral fault and asymmetry between phases. The sensitivity of the degree of asymmetry between is adjustable through a knob adjustment on its front knob.

They have electrical switches (11, 12 and 14) controlled by their electronic circuits that open or close due to their protection.

When the system is energized under all normal conditions it closes the contacts 11 and 14 by opening from 11 to 12. The contact of number 14 remains open if there is asymmetry between the phases of the system if there is a disconnection or drop of either phase or of the neutral.