CN2149704Y

CN2149704Y - Protector for transformer

Info

Publication number: CN2149704Y
Application number: CN 93200871
Authority: CN
Inventors: 张贵华
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-21
Filing date: 1993-01-21
Publication date: 1993-12-15
Anticipated expiration: 2003-01-21

Abstract

The utility model relates to a protector capable of completing the automatic switchover when the transformer deviates from the normal value. A three-phase power supply circuit is connected with the normally open contact of a relay J1 and a thermorelay RJ in series; a control circuit is connected with the relay J1 and the normally-closed contact of the thermorelay in series; a power supply circuit is connected with a thermal protective circuit, wherein, the normally-closed contact of an executive element J2 is connected in a control loop in series. The device has the over-temperature, overloading and open-phase automatic protection function; the utility model can ensure the normal work of the transformer and raise the service life.

Description

Protector for transformer

The utility model relates to a kind of protective circuit device that can finish automatic switchover when circuit departs from normal value, specifically a kind of protective device that is used for transformer.

Power transformer is a power-supply device commonly used since with the overwork of power device, phenomenons such as overload flow often take place, transformer is burnt, influenced normal electricity consumption, cause industrial and agricultural production impaired.The typical transformer protective device is three normally opened contacts and the thermal relay RJ that is connected in series relay J 1 on three-phase power line respectively, and the coil tandem of the normally-closed contact of thermal relay and relay J 1 is in control loop.When over-current phenomenon avoidance occurring, thermal relay RJ action, its normally-closed contact disconnects control loop, makes the J1 outage, and normally opened contact is opened, and disconnects the transformer-supplied circuit, thereby realizes overcurrent protection.Because the operate time of thermal relay is longer, therefore before disconnecting supply line as yet, because of causing transformer oil, overcurrent do not heat up.As occurring over-current state repeatedly, then make the temperature rise of transformer oil surpass critical value, fuel injection event takes place, transformer is broken down.

The purpose of this utility model just provides a kind of protection equipment for transformer, makes it in excess-current excess-temperature situation incision cut-off electric line, implements protection automatically, and has the function of automatic recovery.

The utility model is achieved in that on the basis of existing overcurrent protective device and installs a hot protection mechanism of transformer additional, promptly connects a thermal protection circuit in supply line, and the normally-closed contact of executive component relay J 2 wherein is serially connected with in the control loop.Like this, when transformer is overheated, the thermal protection circuit action, relay J 1 is charged, and normally-closed contact disconnects control loop, makes relay J 1 coil blackout in this loop, thereby disconnects the transformer-supplied circuit.When the transformer temperature reduced, thermal protection circuit recovered again automatically, made the J2 outage, the closing of contact, and the control loop energising, transformer is reworked.

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is an electrical schematic diagram of the present utility model.

As shown in the figure, be connected in series three normally opened contact J1-1, J1-2, the J1-3 of relay J 1 respectively on A, B, C three-phase power line, thermal relay RJ also is serially connected on the three-phase power line, connects power transformer B below.Control loop is drawn from the two-phase of supply line, is connected the coil of relay J 1 behind the normally-closed contact RJ1 of serial connection RJ and the normally-closed contact J2-1 of relay J 2.K switch in the control loop is the switch that starts to work, and can directly control the break-make of power transformer B with this.By also drawing thermal protection circuit on the two-phase of supply line, this thermal protection circuit is paid the side and is connect bridge rectifier D 0 for meet the former side of transformer B1 from supply line's lead-in wire.The output of rectifier connects divider resistance R1 through filter capacitor C1, connect the three-terminal voltage-stabilizing integrated package again, the three-terminal voltage-stabilizing integrated package selects 7086 for use, and its output connects triode BG through relay J 2, and thermistor R2, adjustable resistance R1 and resistance R 4 serial connections become the biasing circuit of BG.The slip contravention of the base stage of BG and adjustable resistance R3 joins.Thermistor R2 increases with temperature rising resistance, has changed the base potential of BG, makes BG change saturation conduction into from ending, and the J2 coil gets electric, and contact J2-1 disconnects, and cuts off control loop, and feeder circuit is ended thereupon.After temperature descended, the R2 resistance reduced, and after reaching a certain numerical value BG is ended, the J2 outage, and the J2-1 adhesive, control loop is connected, and makes the work of transformer automatic recovery of power supply.Adjust the distribution resistance of R3, make BG remain off state under initial condition.Capacitor C 2, C3 provide discharge loop, and voltage-stabiliser tube D1 provides a more stable operating voltage.

For improving the practicality of this device, also can increase the remote controller device, as the usefulness of space switching control.Remote controller can adopt ultrasonic wave or infrared transmitter, and it is inner that receiver is loaded on this device, can be switched on or switched off control loop after received signal.

The utlity model has and surpass allowable temperature protection and surpass peak load protection and the phase shortage function of protection automatically automatically automatically, can guarantee that electric equipment under normal circumstances works, can improve transformer useful life, reduce failure rate.

Claims

1, a kind of Protector for transformer; on three-phase power line, be connected in series three normally opened contact J1-1, J1-2, J1-3 and the thermal relay RJ of relay J 1 respectively; the normally-closed contact RJ1 of thermal relay and the coil tandem of J1 are in control loop; it is characterized in that thermal protection circuit and supply line join, the normally-closed contact J2-1 of executive component relay J 2 wherein is serially connected with in the control loop.

2, Protector for transformer according to claim 1; it is characterized in that thermal protection circuit is the former side who meets transformer B1 from supply line's lead-in wire; pay the side and connect bridge rectifier D 0; rectifier output end connects divider resistance R1 through filter capacitor C1; connect the three-terminal voltage-stabilizing integrated package again; output connects triode BG through relay J 2, and thermistor R2, adjustable resistance R3 and resistance R 4 serial connections become the biasing circuit of BG, and the slip contravention of the base stage of BG and adjustable resistance R3 joins.