DE1209225B - Device for remote control of an alternating current welding device via the welding cable - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

B23k

German KL: 21h-30/15

Number: 1209 225

File number: S 75708 VIII d / 21 h

Filing date: September 12, 1961

Opened on: January 20, 1966

The invention relates to a device for remote control of an alternating current welding apparatus, ζ. Β. a controllable welding transformer over the welding cable, provided with a electrically controlled auxiliary device for adjusting this apparatus, two different loading organs, of which either one or the other to maintain a control current for Control of the welding apparatus in one or the other direction between the welding electrode and the workpiece can be switched, and a ferromagnetic !! System with windings in the welding circuit and in series with a rectification system in the control circuit of the auxiliary device are switched.

A device of this type is from the French Patent specification 1,168,650 known. The Slromtransiomiatorsystem consists of a single one Current transformer, the core of which is saturated during the welding process and therefore no voltage can generate in the control circuit of the auxiliary device, but, if one or the other, from a larger or smaller impedance ordering load orgaii between the welding electrode and the workpiece is switched, a lower or a higher voltage on the grids of two electron tubes presses, in whose anode power circuits relays are switched, through which the auxiliary device is put into effect in one or the other direction. In this known device the control current is an alternating current of the same character as the welding current and is through determines the amplitude of the control current acting on the electron tubes, regardless of whether there is a regulation or not and in a softer direction this regulation takes place. Such a device is for external disturbances and for changes sensitive to the characteristics of each of its elements and has poor selectivity. Further Electron tubes are easily injured and subject to wear and tear.

The invention has the purpose of sounding a device of the type mentioned, the disadvantages of the known device being avoided. It consists in the fact that the load organs are each formed by the series connection of an impedance and a rectifier and differ from one another at least by the reverse direction of the rectifier, that the ferromagnetic system consists of two separate transducers, of which the windings in the control circuit are each in series with one own rectifier and a separate part of the auxiliary pre-device for remote control of a
AC welding machine via the
Welding cable

Applicant:

Willem Smit & Co's Transformatorenf abriek N.V., Nijmegen (Netherlands)

Representative:

Dipl.-Ing. H. Schaefer, patent attorney,

Hamburg 1, Lilienstr. 36

Claimed priority:

Netherlands September 15, 1960 (255 912)

direction, ζ. Β. the coil of a relay, parallel to each other are connected and with the supply voltage, z. B. the welding voltage or part of it, are connected, and that the last-mentioned rectifier reverse blocking directions own. In this device, therefore, a pulsating direct current is used for the control is used, the symbol of which determines the direction of regulation, and the transducers themselves serve as a selective switch in the control or supply circuits of the auxiliary device. The control current gives way therefore in principle from the welding current, so that disturbances in the welding circuit have no controlling effect can have more. The transducers acting as selective switches make the use of electron tubes, Transistors or other vulnerable switching devices that are subject to wear and tear superfluous.

The invention makes it possible to have a single series circuit provided with end contacts an impedance and a rectifier existing, to use loose loading organ, which is responsible for the formation of one loading organ in one Direction and to form the other loading organ in the other direction between the Welding electrode and the workpiece is switched.

It should be noted that the control of a welding machine by means of rectified currents of opposite polarity is known from British patent specification 444 297. But this patent specification refers to an apparatus for welding with direct current, so that a special alternating current

509 779/342

3 4

source for the supply of the control device required welding state and in the state during the rain

that is. In addition, the welding transformer is located in this known development. Through this,

Device uses a polarized relay, which is expensive that circuits 10, 12, 14, 16 and 11, 13, 15,

and is prone to failure; Furthermore, the control 17 must be connected in parallel to one another and only therein

Circuit during welding from welding 5 differ from each other that the rectifier 12 and

Circuit will be off, which will use 13 opposite blocking directions

a heavily loaded switch in the welding current - the phenomena in these circuits interact

circle conditional. The known device is the same, but with a phase difference of 180 °

according to elaborate, intricate in their structure and possess, so that the following considerations

expensive to manufacture. io regarding the one circuit in most

These and other features as well as the cases also apply to the other circuit.
Effect of a device according to the invention in the no-load state flows through the welds in the following with reference to the drawing, the circuits 2, 3 no current and the magnetic the electrical principle diagram of such pre-cores 8, 9 of the transducers 6, 10 and 7 , 11 represents alignment, explained in more detail. 15 finally through the secondary windings 10 and

In the drawing, a controllable welding 11 is magnetized. During the positive half

transformer whose primary side with an alternating period of the supply voltage e can only be through the

power source, d. H. the distribution network, connected circuit 10, 12, 14 and during the negative

and whose secondary side feeds the welding circuit. half periods of this voltage can only be achieved by the

The welding circuit consists of conductors 2 and 3, 20 circuit 11, 13, 15 a current flow. Considered

the welding connected at the end of the conductor 2, if only the circuit 10, 12, 14, 16, then on

electrode 4 and the workpiece 5, which with the end of the beginning of a positive half period of the condensate

of the conductor 3 is connected. sator 16 as a result of the previous positive half-period

In the conductor 2 are the primary windings or which have a certain residual voltage and will be the

primary continuous conductors 6 and 7 of two 25 flux in the magnetic core 8 also as a result of this

Transductors switched. The secondary windings of previous half periods correspond to the positive remanence

10 and 11 of these transducers are each worth in a row, which in the present case is 80 to

with a rectifier 12, 13 and the coil 14, 15 is 85% of the positive saturation value. As soon

of a relay connected in parallel and with the supply voltage during the considered positive

a separate alternating supply voltage e connected half a period, the residual voltage of the condenser

which, as is assumed, has exceeded 16 in phase with the sator, a magnetization

The welding voltage is and therefore also the welding current through the winding 10 and reaches the

voltage itself or a part of it. Core 8 in the state of saturation. After that, the

The rectifiers 12 and 13 opposite winding 10 have almost no impedance and will

Blocking directions. In parallel with the relay coils 14, 15 35 the capacitor 16, which in the preceding

capacitors 16, 17 are connected. This condensate half period current to the coil 14 of the relay

Sators can be omitted in certain cases, up to approximately the maximum value of the

will. The relays actuate contacts 18, 19 or supply voltage e charged.

20, 21, which are in the circuits of the for two rotary during the negative half periods of the

directions executed alternating current motor 22 ge 40 supply voltage can through the circuit 10, 12,

are switched. The motor drives the not shown 14, 16 no current flow, so that the magnetic flux in the

Organs for regulating the welding transformer 1 in core 8 back to the positive remanence value

one way or the other. At the end it drops back and the capacitor 16 becomes the relay coil

Each control area has a limit switch 23 or 24 14 supplied with power. This pulls the relay

opened so that the engine comes to a standstill. 45 continued to anchor. The reverse happens

The limit switches 23, 24 are normally closed. in circuit 11, 13, 15, 17, so that in no-load

In order to generate a control current in the welding state, both relays 14, 15 are attracted to their armature circle between the welding electrode 4 and the hold and the contacts 18 and 20 are closed and workpiece 5 is connected to a load element which is open from the contacts 19 and 21. In this 5 ° state arranged between the end contacts 25, 26, the motor 22 therefore remains de-energized for the control of a series connection of an impedance 27 and one of the transformer 1.
Rectifier 28 consists. This impedance can flow during the welding process, even if it is a voltage-dependent resistance which is minimal at low welding current, a relatively large voltage has a higher and at high span large alternating current through the welding circuit 2, 3 voltage has a lower resistance value. A 55 and therefore also through the primary windings or such a resistor consumes less power, the primary continuous conductors 6, 7 of the Trans are therefore less warm and can therefore produce smaller ducts. If one considers again only the circuit to be implemented as a normal resistance for 10, 12, 14, 16, then the same maximum current intensity, which will emerge for the controls, has the magnetic flux in the core 8 tion is necessary from the following. If you put the load organ in the position shown with full lines at the beginning of the positive half period of the feed, you get the negative remanence value voltage. Initially a control current for the regulation of the welding trans- is therefore the core 8 unsaturated, so that in the formator in one direction, and if the secondary winding 10 of the transductor 6, 8, 10 is a loading element in the dotted indicated relatively high voltage is produced. The inverted state, a control current 65 is obtained. Windings 6 and 10 are wound in such a way that for regulation in the other direction. during the positive half period of the food

The device shown works as follows: The voltage of the welding current has the same polarity,

The welding device can operate in the no-load condition, in which the voltage induced in the winding 10

the supply voltage is directed in the opposite direction. This induced voltage, which is still due to the residual voltage of the capacitor 16 is amplified is much larger than the supply voltage, so that at the beginning of the half-period mentioned, the oppositely directed dul'erence tension over the Clsichric'iiev 12 and the latter cannot pass any current. As a result of the large welding current, the However, core 8 very quickly brought into the positive saturation state. Once reached this state has been, the counteracting voltage across the winding 10 disappears and leaves the supply voltage a current flow through the circuit 12, 10, 14, whereby the capacitor 16 is charged again and the relay 14 is energized. If the size of the supply voltage decreases, so does the magnetic flux in the core 8 from, such that at the moment of the zero crossing of the supply voltage of the magnetic flux has a positive permanence value. Located at the beginning of the negative half cycle of the supply voltage the magnetic flux is therefore in the positive remanence point.

If the direction of the supply voltage reverses, the polarity of the welding sirome also changes. In In this case, a high voltage is generated in the winding 10, which is the sum of the supply voltage and the capacitor voltage is opposite in direction. The differential voltage leaves a current flow through the circuit 10, 12, 14, whereby the relay 14 is again energized. Because in this If counter amp turns are generated and the transducer therefore acts as a transformer, it will take longer before the core 8 reaches the negative saturation state. The electricity therefore remains flowing through circle 10, 12, 14 during a large part of the negative half period. As soon the negative saturation state of the core 8 is reached, the voltage induced in the winding 10 becomes Zero, and since the rectifier 12 cannot pass any current generated by the supply voltage, therefore the current in this circuit also becomes zero. The relay is then fed by the capacitor 16, so that it stays excited. When the welding current passes through zero, the magnetic flux returns to the "den negative remanence point. At the beginning of the following positive half cycle of the supply voltage the magnetic flux is therefore at this point on its characteristic curve. In circuit 11, 13, 15, 17 the same happens, but with a phase difference of 180 ° due to the opposite reverse direction of the rectifier 13.

During the welding process, therefore, both relays 14, 15 also attract their armature, so that the Contacts 18 and 20 are closed and contacts 19 and 21 are open and the motor 22 is de-energized remain. From the above it can be seen that during the positive half cycle of the supply voltage via the rectifier 12 and this voltage during the negative half period the rectifier 13 a very high voltage peak occurs. These voltage peaks can cause the Rectifier affect, so that it is recommended that the windings 10 and 11 by voltage-dependent To bridge resistors, drawn in dotted lines in the drawing and indicated by 29 and 30 are specified.

If you want to put the auxiliary device for adjusting the welding transformer 1 into effect, so must depending on the desired lease of the adjustment either the relay 14 or the relay 15 in this way be excited that it attracts its armature, and the relay 15 or the relay 14 must be de-energized or almost stay de-energized so that it does not attract its anchor. This is achieved with the help of the welding circle 2, 3 connected series connection of the impedance 27 and the rectifier?, 8. If you look at the case where the load current organ drawn in full lines 25 to 28 in the welding circuit 2, 3 is connected. so does not flow during the positive half periods of the supply voltage and the voltage of the welding circuit, but only during the negative half periods of these voltages create a current in the welding circuit.

In the following it is explained that at the beginning of a positive half cycle of the supply voltage the magnetic flux in the core 8 has the negative remanence value. During this period you can the supply voltage generate a current in the circuit 12, 10, 14, which current the core 8 in the brings positive saturation. As long as this state has not been reached. is this stream small, since the winding 10 then forms a large impedance. Most of that half period is now necessary to bring the core 8 into the mentioned state of saturation, so that at the moment, when the winding 10 no longer forms any significant impedance, the amplitude of the supply voltage already does has fallen again to a small value so that the current through the relay 14 remains small, i.e. H. is too small to attract the armature of this relay. It will be clear that in this case the capacitor 16 is only loaded to a relatively small value. During the positive half period the supply voltage, the relay 14 is therefore insufficiently excited. If the positive supply voltage falls to zero, the magnetic flux in core 8 decreases to the positive remanence value, so that at the beginning of the

negative half period of the magnetic flux in the core 8 is located in this remanence point of its characteristic curve.

During the negative half cycle of the supply voltage and the voltage of the welding circuit leaves the rectifier 28 carries the current and a control current flows in the welding circuit 2, 3. This generates electricity in the winding 10 a voltage in the forward direction of the rectifier 12, which voltage with correct dimensioning of the load impedance 27 the sum of the supply voltage and the Capacitor voltage almost the same, but in the opposite direction. The control current through the winding 6 of the transducer drives the core 8 from the positive remanence point into the negative remanence

point of reference. In this case, the induced voltage is not high enough to cause an excitation current to flow through the coil 14 of the relay. The capacitor voltage, which is already low at the beginning of the negative half period and which continues to decrease during this half period, is just as unable to allow a sufficient current to flow through the relay coil 14 if this relay does not attract its armature. Therefore, the contact 18 remains open and the contact 19 closed during both half periods of the supply voltage and the voltage of the welding circuit. When the supply voltage passes through zero after a negative half period, the magnetic flux reverses in the

Core 8 returns to the negative remanence point of its characteristic curve.

When using the loading organ 25 to 28 drawn with full lines, the effect of the Control circuit 11,13,15,17 different from the one above described effect of the circuit 10, 12, 14, 16. As far as the circuit 11, 13, 15, 17 is concerned, the magnetic flux in the core 9 becomes negative at the beginning of a positive half cycle of the supply voltage Have a retentive value. The rectifiers 13 and 28 prevent a current in the circuit 11, 13.15 and flows in the welding circuit 2, 3. The voltage of the capacitor 17 is due to the state relatively high during the previous negative half cycle of the supply voltage, so that the capacitor 17 feeds the relay coil 15 with a current which is sufficient to the armature to attract. The core 9 is therefore at the beginning of the negative half cycle of the supply voltage still in the negative remanence point. A control current flows through during the ao negative half period the welding circuit and a voltage is initially induced in the winding 11, which is the supply voltage and counteracts the capacitor voltage. By the control current in the winding 7, however, the Core 9 brought from the negative remanence point to the negative saturation state very quickly, so that the voltage induced in the winding 11 disappears and the supply voltage increases Sends current through the relay coil 15 and the capacitor 17 almost to the maximum value of the supply voltage loads. If the supply voltage drops to zero during the negative half period, the Core 9 returns to the negative remanence point. In the case under consideration, therefore, the relay 15 pulls his Anchor so that the contact 20 is closed and the contact 21 is open. There, as already explained above has been, the relay 14 can not attract its armature and therefore the contact 19 is closed remains, the motor 22 receives current, and there is an adjustment of the welding transformer 1 in one of the direction of rotation of the motor takes place.

It will be clear that when the loading member 25-28 is turned over, i.e. H. in the dotted line Position is arranged between the welding electrode and the workpiece 5, the relay 14 his Tighten the armature and the relay 15 will remain almost de-energized, so that the motor 22 in opposite Rotate direction and the transformer will be adjusted in the opposite direction.

It should be noted that capacitors 16 and 17 are not always necessary. In some cases they are Relays 14 and 15 so slow that their armature during the half periods of the supply voltage, in which they receive no or too little power, keep attracted. Are the capacitors 16 and 17 are not used, the transducers, the relays, the loading organs and the Supply voltage give other relative values because, as can be seen from the above, the capacitor voltages affect the states in the control circuits.

Claims (5)

Patent claims: 1. Device for remote control of an alternating current welding machine, ζ. Β. a controllable welding transformer, via the welding cable, provided with an electrically controlled auxiliary device to adjust this apparatus, two different loading organs, of which either one or the other to maintain a control current to regulate the welding machine can be switched in one or the other direction between the welding electrode and the workpiece, and one ferromagnetic system with windings that are in the welding circuit and in series with one Rectification system are connected in the control circuit of the auxiliary device, characterized in that that the loading organs are each formed by the series connection of an impedance (27) and a rectifier (28) and differ from each other at least by the blocking direction of the rectifier that the ferromagnetic System consists of two separate transducers, of which the one in the control circuit lying windings (10, 11) each in series with its own rectifier (12, 13) and its own part of the auxiliary device, e.g. B. the coil (14, 15) of a relay, parallel to each other are connected and with the supply voltage, z. B. the welding voltage (1) or part of it, are connected, and that the last-mentioned rectifiers (12,13) are opposite Have blocking directions. 2. Apparatus according to claim 1, characterized in that the lying in the control circuit Windings (10, 11) of the transducers each through a voltage-dependent resistor (29, 30) are bridged, the resistance of which decreases with increasing voltage. 3. Apparatus according to claim 1, characterized in that the lying in the control circuit Relay coils (14, 15) or other load elements each through a capacitor (16, 17) are bridged. 4. Apparatus according to claim 1, characterized in that the two loading organs together by a single series circuit provided with end contacts (25, 26) an impedance (27) and a rectifier (28) existing, loose load organ are formed, that for the formation of one stress organ in one direction and for the formation of the other Load organ in the other direction between the welding electrode and the workpiece is switched. 5. Apparatus according to claim 4, characterized in that the load impedance (27) consists of a voltage-dependent resistor, the resistance of which increases with increasing Tension decreases. Documents considered: German Patent No. 1062 850; British Patent No. 444 297. 1 sheet of drawings 509 779/342 1.66 ® Bundesdruckerei Berlin