CN2135854Y

CN2135854Y - Solid state phase-lose protective relay

Info

Publication number: CN2135854Y
Application number: CN 92232066
Authority: CN
Inventors: 商新民; 周国英
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-07
Filing date: 1992-09-07
Publication date: 1993-06-09
Anticipated expiration: 2002-09-07

Abstract

The utility model relates to a solid state phase-lose protective relay whose sampling signals are firstly rectified and filtered by three paths and then sent to a photoelectric isolation and gate which is composed of three phase interruption indicating element and three photoelectric couplers as driving signals, and the output of the and gate triggers a bidirectional thyristor to work. The circuit of the utility model avoids adoption of triode as an element, which makes the circuit simple and reliable, and the solid state phase-lose protective relay has a self-protective function when a load generates short-circuit.

Description

Solid state phase-lose protective relay

The utility model relates to the open phase protection that various A.C. contactors a kind of and the control three phase electric machine are used.

In the existing solid-state phase failure relay, internal circuit adopts triode inevitably, to realize voltage; the amplification of electric current and conversion, so the kind circuit is many because of intermediate link, circuit is complicated; reliability is reduced, and do not have phase failure indication, be unfavorable for searching intuitively open phase fault.In addition, when in a single day the similar loads such as A.C. contactor that driven are short-circuited, may burn the output stage element in the solid phase-cut off relay.

The purpose of this utility model provides a kind of internal circuit need not adopt triode, and circuit structure is simple and reliable, has phase failure indication concurrently, but when load short circuits the solid-state phase failure relay of self-shield.

The purpose of this utility model realizes by following measure: the sample circuit in the solid-state phase failure relay internal circuit is connected into the Y type; three groups of rectifier bridges that are connected in the sample circuit take out corresponding three-phase current signal; as sampling current; detect whether phase shortage of three phase supply circuit respectively; sampling current divides three tunnel light-emitting diodes of still supplying with three photoelectrical coupler transmitting terminal inside respectively with three tunnel forms after RC filtering as drive current, and the light-emitting diode of respectively connecting in three loops of sample circuit is done phase failure indication.Three photoelectrical coupler internal interface receiving ends are the bidirectional triode thyristor element, after its series connection, constitute three input photoelectricity and isolate triggering and door, be used for controlling the break-make of a bidirectional triode thyristor of back level, the working power of the external A.C. contactor of this SCR control, whether decision gives electricity.

When the power supply of supplying with three phase alternating current motor not during phase shortage; three light-emitting diodes as indication are bright entirely; show that three phase mains is normal; back level bidirectional triode thyristor in the solid-state phase failure relay is in conducting state at this moment; the coil power of A.C. contactor is switched on, and three phase alternating current motor can turn round under the normal control of A.C. contactor.When the arbitrary phase phase failure of three phase mains; then extinguish with this corresponding light-emitting diode; show this phase phase failure; at this moment; just automatic cut-off of back level bidirectional triode thyristor in the solid-state phase failure relay, the power supply of sever supply ac contactor coil makes the A.C. contactor tripping; motor just shuts down, and reaches the purpose of protection three phase electric machine.

When preventing load short circuits, damage the back level bidirectional triode thyristor in the solid-state phase failure relay, the overflow protecting element of in output loop, having connected.

Advantage of the present utility model is: adopt the three-phase sampling method, the connecting to neutral line also can not finished open phase protection, does not adopt triode in the circuit, and circuit is simple and reliable, and volume is little, has phase failure indication concurrently, but self-shield during load short circuits.

The utility model is the new design of solid-state phase failure relay internal circuit.

Accompanying drawing 1 is solid-state phase failure relay overall package profile schematic diagram.

Accompanying drawing 2 is solid-state phase failure relay internal circuit configuration block diagram.

Accompanying drawing 3 is solid-state phase failure relay internal electric schematic diagram.

Accompanying drawing 2 shows solid-state phase failure relay internal circuit to be made up of following components, and it comprises: sample circuit, filter circuit, phase failure indicator elment, conversion and circuits for triggering, drive circuit, load short circuits self-shield element.All element is installed on the printed circuit board, and is packaged in the insulation crust 3.

Accompanying drawing 3 shows solid-state phase failure relay internal electric schematic diagram, and its principle is: sample circuit is sample resistance 1R ₁, 1R ₂, 1R ₃And rectifier bridge Q ₁, Q ₂, Q ₃Be connected into Y type circuit and draw center line N.A, B, C link to each other with the following contact of three phase mains fuse respectively.When three phase mains not during phase shortage, rectifier bridge Q ₁, Q ₂, Q ₃Dc output end all-wave pulsating direct current signal output will be arranged, this signal is via capacitor C ₁, C ₂, C ₃And resistance 2R ₁, 2R ₂, 2R ₃Behind corresponding respectively No. three filter circuits of forming, become needed three road direct current signals, this signal is respectively as three photoelectrical coupler GD ₁, GD ₂, GD ₃The drive current of middle transmitting terminal light-emitting diode.And drive phase failure indication light-emitting diode D simultaneously ₁, D ₂, D ₃GD ₁, GD ₂, GD ₃In the inside receiver all adopt the bidirectional triode thyristor pattern, will receive on the control utmost point G of bidirectional triode thyristor T in the drive circuit after their series connection, constitute photoelectricity isolate three with a door triggering form.GD ₁, GD ₂, GD ₃Conversion and circuits for triggering have been formed jointly.Because three phase mains this moment phase shortage not, three road sampling loops all have sampling current to flow through, then D ₁, D ₂, D ₃All conductings and luminous, the indication three phase mains is normal.While GD ₁, GD ₂, GD ₃Transmitting terminal internal body diodes also conducting is luminous, and three bidirectional triode thyristors that this light signal promptly is coupled to the internal interface receiving end make its whole conductings.Triggering signal just is added on the trigger electrode G of T by 3R, makes the T conducting, has connected the power supply 1 of the external A.C. contactor that is serially connected in 2 ends, possesses normal entry condition.In case three phase mains is arbitrary the phase failure takes place mutually, this phase just can not get sampling current, D ₁, D ₂, D ₃In promptly extinguish with this corresponding light-emitting diode, provide the phase failure and indicate.While GD ₁, GD ₂, GD ₃A bidirectional triode thyristor of middle receiving terminal just ends, and makes the trigger electrode G of T can not get triggering signal, and T just ends, and has cut off the power supply of the external A.C. contactor that is connected on 2 ends, and it is not started.After open phase fault is got rid of, can restart.Thereby protected three phase electric machine.

When external A.C. contactor even load is short-circuited, be connected on the protection component R in the load circuit _LCan be because of the automatic disconnection of transient flow super-high-current, make that T is unlikely to be burnt.

R in the drive circuit _GBe anti-interference resistance, resistance R _C, capacitor C ₄Form the peak voltage protective circuit.

Claims

1, a kind of solid-state phase failure relay; form by sample circuit, filter circuit, conversion and circuits for triggering, drive circuit; it is characterized in that: this solid-state phase failure relay also comprises phase failure indicator elment and load short circuits self-shield element, and sample circuit and filter circuit are three the tunnel.

2, as the said solid-state phase failure relay of claim 1, it is characterized in that: sample circuit is by forming with A, B, C three phase mains corresponding three tunnel, and inside is connected into the Y type, and draws center line N, and sample circuit is by resistance 1R ₁, 1R ₂, 1R ₃And rectifier bridge Q ₁, Q ₂, Q ₃Form 1R ₁With Q ₁Series connection, 1R ₂With Q ₂Series connection, 1R ₃With Q ₃Series connection.

3, as the said solid-state phase failure relay of claim 1, it is characterized in that: filter circuit is three the tunnel, respectively with rectifier bridge Q ₁, Q ₂, Q ₃Dc terminal link to each other, filter circuit is by capacitor C ₁, C ₂, C ₃And resistance 2R ₁, 2R ₂, 2R ₃Form C ₁, 2R ₁With Q ₁Link to each other C ₂, 2R ₂With Q ₂Link to each other C ₃, 2R ₃With Q ₃Link to each other.

4, as claim 1,2 or 3 said solid-state phase failure relays, it is characterized in that: phase failure indicating circuit is by light-emitting diode D ₁, D ₂, D ₃Form D ₁With 2R ₁Series connection, D ₂With 2R ₂Series connection, D ₃With 2R ₃Series connection.

5, as claim 1,2 or 3 said solid-state phase failure relays, it is characterized in that: the transition trigger circuit is that the inner receiver of employing is three photoelectrical coupler GD of bidirectional triode thyristor element ₁, GD ₂, GD ₃And resistance 3R forms GD ₁Transmitting terminal and D ₁, 2R ₁Series connection, GD ₂Transmitting terminal and D ₂, 2R ₂Series connection, GD ₃Transmitting terminal and D ₃, 2R ₃Series connection, GD ₁, GD ₂, GD ₃Output series connection after connect with 3R again and constitutes three input photoelectricity and isolate and a form, link to each other with the trigger electrode G of bidirectional triode thyristor T in the drive circuit with gate output terminal.

6, as claim 1,2 or 3 said solid-state phase failure relays, it is characterized in that: load short circuits self-shield element, by overflow protecting element R _LForm R _LBe connected in the output loop of T.