CN2035541U - Phase-losing protector for three phase power - Google Patents

Abstract

Disclosed is a phase-losing protector for three phase power. The reliable function of phase-losing protection can be realized by taking a three-contact relay controlled by thyristor as a major element. An external power source is not required. The protector has the advantages of simple structure and tiny power consumption.

Description

Phase-losing protector for three phase power

A kind of three-phase electricity open phase protector belongs to the electronic equipment field.

Three-phase alternating current is the main electric power source of various industrial equipments; but in case the phase shortage accident occurs; regular meeting causes serious consequences such as burn-down of electric motor; for this reason; open phase protector has been used in some place at present, but because of the most complex structure of this class protector, the high and need external power supply of cost; so range of application is wideless, cause at present many motors all under no phase shortage guard mode, to move.

The three-phase electricity open phase protector that the utility model proposes is simple in structure, and dispense with outer connecting power is so overcome the weak point of present existing open phase protector.

Accompanying drawing 1 is the circuit theory diagrams of this open phase protector, and accompanying drawing 2 is appearance assumption diagrams, and its structure and operation principle are described in detail in detail below.

As shown in Figure 1, open phase protector comprises normally opened contact press button QN, normally-closed contact press button TN, three contact switch relay J, voltage current transformer L, bidirectional triode thyristor BR, Zener diode D₁、D ₂ Three contact switch 1 of relay, 2,3,4 and 5,6 are connected on respectively on the three-phase wire, and its coil one end links to each other with C phase line upper contact 5 by QN, TN, and the other end links to each other with A phase line upper contact 1; F point place has a line to link to each other with bidirectional triode thyristor BR between switch QN, TN, and the BR other end links to each other with contact 6, and the while is as the C ' phase output line of protector; B phase line upper contact 4 is by the elementary B ' phase output line that becomes protector of L; The D that oppositely is being connected in series₁、D ₂Be connected across the secondary of L, an end of L level extremely links to each other with BR control, and the other end links to each other with the F point.

Starter is pressed QN, electric current through TN, coil to the A phase line, relay contact closure, B phase line current elementary through L simultaneously, secondary voltage makes BR trigger (D ₁, D ₂Play protection, stabilization), C phase line current through BR, TN and coil to the A phase line, unclamp QN after, adhesive is kept in all contacts.In case no matter phase shortage lacks A, B, the arbitrary phase of C, clearly controllable silicon BR loses turn-on condition, in the relay coil no current is flow through relay behind the QN and discharges thereby unclamp, and has so just realized the purpose of open-phase protection.As long as press TN when normal need in service stop.

Accompanying drawing 2 is protector structure figure, and on the circuit board 2 of foregoing circuit in shell 1, three ends of shell 1 one sides are input; connect A, B, C triple line respectively; three ends of opposite side are three-phase output end A ', B ', C ',, push-button switch QN, the button of TN all is exposed at outside the shell 1.

Claims (1)

1, a kind of three-phase electricity open phase protector, its internal circuit comprise normally opened contact push-button switch QN, normally-closed contact push-button switch TN, three contact switch relay J, voltage current transformer L, bidirectional triode thyristor BR and voltage stabilizing didoe D ₁, D ₂, it is characterized in that:

(1) three contact switchs of relay J 1,2,3,4 and 5,6 are connected on respectively on three-phase wire A, B, the C, and relay coil one end links to each other with contact 5 by QN, TN, and the other end links to each other with contact 1;

(2) F point place is wired between switch QN, TN links to each other with BR, and the BR other end links to each other with contact 6, simultaneously as protector C ' phase output line;

(3) contact 4 is by the elementary protector B ' phase output line that becomes of L;

(4) D that oppositely is being connected in series ₁, D ₂Be connected across the secondary of L, the secondary end of L extremely links to each other with BR control, and the other end links to each other with the F point;

(5) contact 2 connects protector A ' phase output line.

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