SU1619366A1 - Device for protecting power diodes of welding rectifier - Google Patents

Description

one

(21) 4078084/07

(22) 11-005

(46) 07.01.91. Bugk number 1

(71) Tbilisi Electric Welding Equipment Plant named after E. O. Paton

(72) D. A. Krikheli and M. G. Devdariani

(53) 621.316.925 (088.8)

(56) USSR Copyright Certificate No. 534825, class, H 02 H 7/09, 1975.

USSR Author's Certificate No. 187874, cl. H 02 H 7/12, 1963.

(54) DEVICE FOR A PLANT OF A WELDING RECTIFIER VENT

(57) The invention relates to electrical engineering. The purpose of the invention is to increase the speed and reliability of the device for protection of welding rectifier valves. In good condition, the welding rectifier transistors 1,

if

2 are locked by voltage rectifier 7 and the contacts of relay 5 in the coil and coil 10 circuit are closed. During the breakdown of the valve, the voltage of the rectifier 7 decreases and the transistors 1, 2 are opened by currents entering their bases through the resistors 4, 6. Relay 5 is activated and opens the coil circuit of the actuator 10, which disconnects the rectifier from the network. The parameters of the device are chosen so that the relay 5 does not operate when the rectifier output closes at the moment of ignition of the welding arc due to the voltage drop across the connecting conductors. The performance is increased by using a transistor amplifier, while the reliability is increased by eliminating false tripping of the protection. 1 il.

J

ABOUT

S

00

o o)

The invention from Ositne to electrons is possible and can be 5, using a method to protect welding cells from breakdowns of valves.

The purpose of the invention is to increase the speed and reliability of the device for protection of welding rectifier valves.

The qepTejKe depicts a welding circuit of a rectifier with a device to protect the valves.

The device contains transistors 1 and 2, a two-phase rectifying unit Ze, the negative terminal of which is connected to the collector of transistor 1 and the emitter of transistor 25 and through resistor 4 to the base of transistor 1s evilly connected to a 5S relay.

ONE SIDE TO ADVANCE / CONSTITUTION

of the rectifying unit 3 and through the RESISTOR b - to the base of the transistor 29 and on the other hand to the emitter of transistor 1 and to the collector of transistor 2e. The three-phase rectifying block 7 is connected via a positive terminal through a resistor 8 to the base of the transistor 1, and the negative terminal is connected through a resistor 9 to the base of the transistor 2 "

The opening contact of Rale 5 is included in the coil circuit of the magnetic starter. Switch 11 serves to switch the power transformer of the welding rectifier, eating 12 into a star or a triangle. Transformer 13 is pre-assigned for galvanic isolation of the device from the mains.

The device works in the following way.

When the welding valve rectifier 2 is working properly, the transistors 1 and 2 are closed by the voltage applied to their bases through resistors 8 and 9 from rectifier 1. To prevent false triggering, the devices are wired at the time of ignition of the arc during short circuit. The current resistors 4E 8 and 69 9 are selected with the expectation j so that at the moment of short-circuiting the electrode with the product (arc firing time), the transistors 1 and 2 are locked. For this it is necessary that the device be powered at low voltages.

In addition, a significant role in the prevention of false alarms of the device, the play of the voltage drop will connect the old conductors from you

five

the progress of the welding rectifier to the welding electrode, Since the varnish acrr at the output of block 7 at the time of the prose of one of the power valves is much less than the voltage at the output of block 7 at the moment of short-circuiting the electrode with the product, the device works only in case of breakdown of the valve.

In the event of the failure of any power valve of a short circuit in the secondary circuit of a power transformer, the displacement at the bases of transistors 1 and 2 increases, they open, relay 5 operates and opens a contact in the circuit of magnetic actuator 10, which releases measles. The power supply of the rectifying unit 3 is carried out from the primary winding of the power transformer (included in the welding rectifier) s from which the answer is taken - corresponding to the selected operating voltage of the electromagnetic relay 5,

Claims (1)

Since the welding rectifier has two ranges of operating currents - small and large, during operation it is necessary to switch it, which is done by switch 11 entering the welding rectifier 12, which is equipped with a microswitch and a cam for this purpose. Invention Formula A device for protecting the valves of a welding rectifier made in the form of a three-phase transformer, the secondary windings of which are connected to the input terminals of a three-phase bridge rectifier containing a magnetic starter, the contacts of which are intended to be connected between the input terminals of the welding rectifier and the corresponding conclusions of the primary windings of the transformer, and an electromagnetic relay9 winding through its closing contact is connected to the output of the auxiliary power source, and the opening contact is electrically posledovatelno1 ferromagnetic relays included, with the winding of the magnetic actuator, characterized in that in order to improve performance and reliability ustroystvas introduced three-phase bridge rectifying Mi- Tel, four resistors and the two transistors of mutually opposite conductivity types, wherein the auxiliary power source is in the form sd51619366b a single-phase bridge rectifier with a high-voltage capacitor, respectively, through the third and a four-way capacitor, the input output resistors to the output pins of the three-phase bridge rectifier of the auxiliary voltage source, are designed to connect to the first transistor output pins of the secondary transducer Pa and the emitter of the second transistor of the windings of the welding transformer are connected to the first output of the switching rectifier, the output pins, the corresponding contact of the electromagnetic body, through the first The second and second output pins of which are connected to the electromagnetic supply are connected to the bases of the corresponding JQter of the first and the collector of the second transistor, connected, of the transistors.