MEASURING BODY FOR CURRENT PROTECTION OF ELECTRIC MOTOR Russian patent published in 2017 - IPC H02H3/08 H01H51/28 

FIELD: electricity.

SUBSTANCE: body comprises a fixing unit made in the form of a rectangular parallelepiped, at the bottom of which, near the first side face, an adjustment unit, the first and second terminal blocks are fixed. Near the other side face opposite the first one, the third and fourth terminal blocks are fixed. At the bottom of the fixing unit, in its center, four rectangular housings are fixed, in each of which a hermetically sealed reed relay is located: the first, second, third and fourth, respectively. The first hermetically sealed reed relay is equipped with four control windings, and the second third and fourth hermetically sealed reed relay - with one control winding. The first and second control windings of the first hermetically sealed reed relay are connected to the first terminal block with their ends. The third and fourth control windings of the first hermetically sealed reed relay are connected to the third terminal block with the first ends, and to the first control winding ends of the third and fourth hermetically sealed reed relay with the second ends, respectively. The first end of the control winding of the second hermetically sealed reed relay is connected to the third terminal block. The control windings of the second, third and fourth hermetically sealed reed relays are connected to the fourth terminal block with the second ends. The first, second, third and fourth hermetically sealed reed relays are connected to the inputs of the adjustment unit with their contacts. The outputs of the control unit are connected to the second terminal block. Holes are made in the first side face and at the bottom of the fixing unit, near the terminal blocks, through which the winding ends of the phases A and B of the electric motor are connected to the first terminal block on the side of the zero leads, the wires connecting the control unit with the control current source and the motor switch cut-off coil are connected to the second terminal block, the winding ends of the phases A, B, C of the electric motor on the supply side are connected to the third terminal block, a cable feeding the electric motor is connected to the fourth terminal block. At the corners of the fixing unit, holes are made for its attachment to the electric motor terminal box.

EFFECT: implementation of differential protection and protection against phase failure of a low-power electric motor.

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