RU2090324C1 - Welder electric circuit - Google Patents

Abstract

FIELD: mechanical engineering; semiautomatic resistance welders; electrical equipment. SUBSTANCE: circuit has automatic circuit breaker, step selector, welding transformer, time controller, contactor and pneumatic valve contactor and also fuse and switch-on pedal. Time controller is built around logic microcircuits. Contactors are built around thyristors. EFFECT: enlarged operating capabilities. 6 cl, 4 dwg

Description

 The invention relates to the field of electrical equipment for welding units and can be used in the construction of semi-automatic welding units used for resistance welding of parts, mainly from low-carbon steel.

 Known electrical circuits (see, for example, the technical description for welding units MT-1610 and M-2510, p. 10-11), contains, as a rule, components such as a circuit breaker, stage switch, welding transformer, time controller, contactor innitron, pneumatic valve contactor, fuse and switch-on pedal, moreover, the circuit breaker is connected to the welding transformer via a step switch, and by means of a time controller with contactors and a switch-on pedal. The fuse is connected to the circuit breaker.

 The disadvantages of the known scheme should be recognized as low reliability, low accuracy of setting the time of the welding technological cycle, low reliability and electrical safety of welding associated with the need to supply cooling water for ignitrons, the presence of a mercury cathode in ignitrons, as well as the presence of a relay system in the time controller and contactors.

 The technical problem to which the present invention is directed is the development of an improved electrical circuit of a semi-automatic welding unit.

 The technical effect of the implementation of the present invention is the development of a highly reliable and safe circuit that allows with high accuracy to improve the time intervals of the technological cycle.

 The above technical effect is achieved by the fact that instead of an ignitron contactor, a contactor for at least two countercurrently connected thyristors is used, the pneumatic valve contactor is also made on thyristors, the time controller is based on logic circuits and an amplifier.

 Mostly, the contactor is made on the basis of two countercurrently connected thyristors, a time controller based on seven logic circuits connected to a transistor amplifier, a pneumatic valve contactor based on a low-power thyristor.

 The applicant notes that although the use of the above options is indeed preferable today, however, there are many options for another design of these nodes. Mainly at the output of each microcircuit, thyristor and transistor, a control terminal is connected, which can be connected to a separate output, in particular an LED or to a connector block.

 The applicant notes that the above technical effect is achieved only when using the totality of the essential features introduced by the applicant in an independent claim. The features introduced by the applicant in the dependent claims develop and clarify the features in the independent claims.

The invention differs from the closest analogue in that:
a) the contactor is made on the basis of at least two countercurrently connected thyristors;
b / pneumatic valve contactor is based on a thyristor;
in / time controller is based on the assembly of the amplifier logic circuits.

The invention is illustrated in graphic material, where in FIG. 1 is a structural diagram of a welding unit, FIG. 2 is a structural diagram of a time controller, FIG. 3 is a circuit diagram of a contactor, and FIG. 4 is a circuit diagram of a pneumatic valve contactor. The applicant used the following notation: figure 1 shows:
1 circuit breaker
2 thyristor contactor,
3 gear selector,
4 welding transformer,
5 power supply,
6 time relays
7 pneumatic valve contactor,
8 winding of a pneumatic valve,
9 starting pedal,
10 electrodes;
figure 2 shows:
10 starting device
11 electronic compression time relay,
12 electronic welding time switch,
13 electronic forging time relay,
14 master oscillator
15 trigger
16 amplifier control circuit,
17 power amplifier thyristor contactor,
18 power amplifier contactor pneumatic valve;
FIG. 3 are shown:
19 diodes
20 resistors,
21 thyristors
22 pulse transformer;
FIG. 4 are shown:
23 diodes;
24 resistor;
25 thyristor
26 pulse transformer.

 The time controller is made on logic circuits of the 15 155, 555, 218 series and transistors of the KT 315, KT 807 series, the contactor is made on T 320, T 630 type thyristors. The pneumatic valve contactor is made on KU 208 thyristor. Control outputs can be connected to the LED ( am) type AL 307.

 The claimed electrical circuit operates as follows: FIG. 1 after turning on the circuit breaker / 1 /, the mains voltage of 380 V is supplied to the thyristor contactor 2, power supply 5. The circuit design of the electronic time relay 6 allows you to set all the electronic time relays (Fig.2 p. 11, 12, 13) to the zero position. The welding machine is ready for use. The operator handles the control knobs on the electronic time switch 6 to set the specified welding mode according to the flow chart (the values of the compression time, welding, forging, and the step switch 3 maximum welding current).

 After pressing the start pedal 9, an electronic time relay 6 is started, which provides control of the thyristor contactor 2 and the pneumatic valve contactor 7, according to the specified welding mode.

 After the end of the welding cycle, the system returns to its original state. The regulation range of the electronic time relay is selected according to the nameplate data for the used machines.

 Consider the operation of the electronic time relay 6 in FIG. 2: after pressing the start pedal (Fig. 1, p. 9), the start device 10 is activated, which starts the electronic compression time switch 11 and trigger 15. The signal from the trigger 15 enters the control circuit of the amplifiers 17 and then to the power amplifier 18, thereby turning on pneumatic valve. The compression time will be determined by the setting for the electronic compression time switch 11. After the electronic compression time switch 11 has been activated, the electronic welding time switch 12 is started and after its operation, the signal goes to the control circuit of the amplifier 17, then to the power amplifier 18, thereby turning on the thyristor contactor, which feeds power supply to the welding transformer (Fig. 1 p. 4). The welding time will be determined by the setting for the electronic welding time switch 12. After the electronic welding time switch 12 has been completed, the thyristor contactor is turned off and the forging timer 13 is started, after which the pneumatic valve is turned off and a command is sent to return the system to its initial state. The thyristor contactor (Fig. 3) and the pneumatic valve contactor (Fig. 4) are controlled by a pulse voltage with a frequency f and values determined by the type of selected thyristors.

 The use of this electrical circuit allows you to exclude all relay contacts, both low-current and power; an ignitron requiring water cooling; relay starter for ignitron; preliminary training before installation, preparation for work (at least 30 minutes).

 Improve the quality and reduce welding time by turning on the thyristor at a lower voltage than the ignitron and the stability of turning on the thyristor. High stability of the electronic time switch and increasing the reliability of its operation, as well as increasing the productivity of the machine by reducing welding time with good quality, the establishment of control points allows you to diagnose the health of the entire system, up to identify a failed element without the use of special equipment, which facilitates maintenance unit. Provides electrical safety operation, as the control circuits are galvanically isolated from power circuits; quick readiness of the unit to work immediately after turning on the automatic shutdown.

 The use of simple and cheap elements of the electrical circuit simplifies the maintenance of the welding unit.

Claims (6)

 1. The electrical circuit of the welding unit, comprising a circuit breaker, a voltage stage selector, a welding transformer, a time regulator, a voltage stage selector contactor, a pneumatic valve contactor and a pedal, the circuit breaker being connected to a welding transformer through a voltage stage selector contactor and a voltage stage selector, and controller inputs time are connected to the circuit breaker and pedal, and the outputs to the contactor of the voltage stage selector and pneumatic valve contactor, characterized in that the time controller contains amplifiers and is made on logic circuits, the voltage step switch contactor contains at least two counter-parallel connected thyristors, the pneumatic valve contactor contains one thyristor.  2. The circuit according to claim 1, characterized in that the contactor of the voltage step switch comprises two thyristors in parallel-connected.  3. The circuit according to claim 1, characterized in that the pneumatic valve contactor contains a low-power thyristor.  4. The circuit according to claim 1, characterized in that the time controller contains seven logic microcircuits, power amplifiers of the thyristor contactor and pneumatic valve contactor, the inputs of the amplifiers connected to the outputs of one of the microcircuits.  5. The circuit according to any one of paragraphs.2 to 4, characterized in that at the output of the microcircuits and thyristors the connection of the test leads is made.  6. The circuit according to claim 5, characterized in that the control terminals are connected to a common connector.

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