CN2132324Y

CN2132324Y - Phase-failure protector for electric machine

Info

Publication number: CN2132324Y
Application number: CN 92232029
Authority: CN
Inventors: 杨中模
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-05
Filing date: 1992-09-05
Publication date: 1993-05-05
Anticipated expiration: 2002-09-05

Abstract

The utility model relates to a phase-failure protector for an electric machine, which is a phase-failure protective device for the electric machine, wherein, the device is arranged in a running circuit of the electric machine and is matched with a control loop of the electric machine. The phase-failure protector for an electric machine is composed of a resistor, a capacitor, diodes, controlled silicon, a resetting button, a transformer and a miniature relay, wherein, the output contacts of the miniature relay are connected to the control loop of the electric machine. When the accident of phase failures or phase-absence of the electric network arises, the controlled silicon is triggered to be conducted, so that the miniature relay can act to cause a contactor to lose electricity, and thus the running loop of the electric machine is cut off. The utility model has the advantages of simple circuit, high reliability, convenient installation and operation. The utility model can prevent the electric machine being burnt because of the phase failure or the phase-absence. Therefore, the utility model is particularly suitable for being used as a phase failure protective device of AC electric machines.

Description

Phase-failure protector for electric machine

The utility model relates to a kind of alternating current machine that is installed in and moves in the circuit and the motor open phase protection that cooperates with motor control loop.

In order to guarantee the safe operation of motor; all safety precautions have extensively been taked; as in motor operation circuit, fuse being installed the operation motor is carried out short-circuit protection, in motor operation circuit, thermal relay is installed the operation motor is carried out overcurrent, overload protection etc.But, not see as yet in the prior art and can carry out the device of open phase protection the operation motor, this just makes to safety precautions of operation motor perfect inadequately, in case when the three phase mains phase failure or phase shortage occurring, motor is burnt because of the phase failure or phase shortage.

The purpose of this utility model is a kind of open phase protection that is exclusively used in three phase alternating current motor of design, causes burning because of phase shortage or the phase failure to prevent to move motor.

To achieve these goals; the utility model during according to the phase failure three-phase alternating current star connect the principle of neutral point current sum offset from zero; design an open-phase protection circuit, this open-phase protection circuit is connected in the motor operation circuit and with motor operation control loop and cooperates.When the phase failure or phase shortage appear in three-phase alternating-current supply, trigger the controllable silicon conducting and also control the midget relay adhesive, and and then make the A.C. contactor dead electricity, cut off motor power by motor operation control loop, realize open phase protection.Be described in further detail below in conjunction with the technical characterictic of specific embodiment the utility model motor phase failure protector.

Accompanying drawing 1 is the open-phase protection circuit figure of the utility model motor phase failure protector;

Accompanying drawing 2 and accompanying drawing 3 are the two kind connection schematic diagrames of phase failure protector in motor operation circuit.

With reference to the accompanying drawings 1,2,3; the utility model motor phase failure protector is to be made of housing and the open-phase protection circuit that is installed in the housing; open-phase protection circuit is mainly by resistance R 1-R4; diode D1-D8; capacitor C 1, C2, controllable silicon BT, reset button N; transformer T, light-emitting diode H and midget relay J form.Resistance R 1-R3 is connected in the motor three-phase alternating-current supply respectively and forms the star three-phase balancing load, and its balance point a is through diode D4, resistance R 4 and transformer T primary coil ground connection.Diode D1-D3 is connected to respectively in the motor three-phase alternating-current supply, and itself and contact b be through reset button N, controllable silicon BT and transformer T primary coil ground connection.The controllable silicon BT control utmost point is connected to D4 and R4 tie point, and is in parallel with R4 after capacitor C 1 is connected with C2.Diode D5-D8 forms bridge rectifier and is serially connected with in the transformer T secondary coil with midget relay J, and J output contact J0J1 is connected in the motor operation control loop, and in parallel with J after resistance R 4 is connected with Light-Emitting Diode H, H is installed on the case panel.

When phase failure protector inserted three-phase alternating-current supply, if there is not the situation of the phase shortage or the phase failure, then its neutral point a current potential was zero, and the electric current by D4, R4 and T primary coil is zero, R4 two ends absence of voltage, the controllable silicon conducting that is not triggered.When A, B, any phase phase shortage of C or the phase failure, a point current potential offset from zero, have electric current to pass through D4, R4 and T primary coil this moment, and the last generation of R4 voltage drop makes the controllable silicon triggering and conducting.Be added to the primary coil of T through the dc pulse moving voltage of D1-D3 rectification by controllable silicon, through becoming direct voltage after the coupling of transformer T and the D5-D8 rectification, drive J and make its output phase failure relay signal, light-emitting diode H is bright to open the indication circuit phase shortage or the phase failure.

It shown in the accompanying drawing 2 one of phase failure protector connection in motor operation circuit.Phase failure protector DX is connected on fire end under the contact of A.C. contactor Q, and the output contact J0J1 of phase failure protector is connected in the motor operation control loop, and generally phase failure protector is failure to actuate, and motor normally moves.When the three phase mains phase shortage or the phase failure, phase failure protector DX action, its output contact J0J1 becomes Chang Kai and makes A.C. contactor Q dead electricity, and motor operation major loop disconnects, and realizes open phase protection.At this moment, the output contact J0J1 of phase failure protector DX becomes normally closed again, for prepare next time.

It shown in the accompanying drawing 3 phase failure protector another connection in motor operation circuit.Phase failure protector DX is connected on fire end on the contact of A.C. contactor Q, and the output contact J0J1 of phase failure protector DX still is connected in the motor operation control loop.In this case, after the motor dead electricity was protected, the reset button N that must press phase failure protector just can make phase failure protector output contact J0J1 become normally closedly by often opening, and motor could start once more.

The utility model circuit is simple, reliable, easy to install, can avoid motor to be burnt because of the phase failure or phase shortage effectively, so be particularly suitable for being used as the open phase protection of alternating current machine, also can be used for electrical network and circuit phase shortage are monitored.

Claims

1, a kind of alternating current machine that is installed in moves in the circuit and the motor open phase protection that cooperates with circuit for controlling motor, it is characterized in that it is to be made of housing and the open-phase protection circuit that is installed in the housing; Described open-phase protection circuit is by resistance R 1-R4; diode D1-D8; capacitor C 1; C2; controllable silicon BT; reset button N; transformer T; light-emitting diode H and midget relay J form; R1-R3 is connected in the alternating current machine three phase mains respectively and forms the star three-phase balancing load; its balance point a is through D4; R4 and T primary coil ground connection; D1-D3 is connected to respectively in the alternating current machine three phase mains; itself and contact b are through N; BT and T primary coil ground connection; the BT control utmost point is connected to D4 and R4 tie point; it is in parallel after C1 connects with C2 with R4; D5-D8 is serially connected with in the T secondary wire coil with J after forming bridge rectifier; J output contact J0J1 is connected in the motor operation control loop, and is in parallel with J after R5 connects with H.