What is an oscillator in welding - Metals and their processing

DIY oscillator for inverter

The quality of welding of difficult-to-weld metals: stainless steel, some aluminum and non-ferrous alloys depends on the stability of the electric arc. A welding oscillator is used as a stabilizer - a device for generating a pulse discharge. For additional connection to the welding machine, buy a ready-made device or use your own creation; you can make an electronic device for welding aluminum and complex steels yourself.

An oscillator is another current source for a welder, an electrical device designed to generate a pulse. When an oscillator is connected, the welding machine or inverter maintains the arc without necessarily making contact between the workpiece and the electrode. Combustion is ensured by the superposition of currents from the main source and the oscilloscope. Welding is stabilized, a uniform seam is formed, and the risk of sticking during a drop-by-drop short circuit is reduced when using consumable electrodes.

Welding oscillator device

When considering the circuit diagram, you need to choose a connection method; the welding oscillator (factory-made or self-assembled) is connected to the welder in one of two possible ways:

serial connection is effective when working with aluminum and aluminum alloys, ensuring uninterrupted long-term burning of the electric arc;
with parallel connection, stainless steel is welded, such a connection is of a short-term nature.

Oscillator circuit diagram

Any oscillator used for the welding process is assembled from a similar set of electrical parts:

The standard spark gap is single-circuit and consists of an induction coil (ignition) with a capacitor connected in series to store the charge. The spark gap generates damped oscillations. Tungsten electrodes are used as contacts.
Two inductors, with high resistance to alternating current and low resistance to direct current, act as chokes. At the output, the voltage increase is delayed and slowed down.
The current is converted in voltage and frequency by a step-up transformer up to 6 kV. Mount a high-power model that produces a frequency of up to 250 Hz.
The generated pulse is transmitted to the welding inverter by the output transformer unit (the inductance principle is used).
The control unit includes two components: a stabilizer and a trigger mechanism.
Fuses ensure safe operation of the oscillator (when creating DIY devices, safety precautions cannot be discounted).

The arrester and additional coils perform the function of a rectifier created with the help of one’s own hands.

When using an oscillator while welding, there is an increased risk of electric shock and protection is required. The increase in frequency and voltage occurs instantly, in a split second.

Principle of operation

Generation consists of several sequential operations; for clarity, it is better to list them:

current supply;
The capacitor is charged from the boost winding;
when the container is fully charged, the control unit sends a signal to the spark gap;
a breakdown discharge occurs;
the oscillatory circuit is short-circuited;
damped oscillations are supplied to the working area;
the fuse opens the electrical circuit when the capacitor is released;
Due to the ionization of air or shielding gas, an arc flashes.

Using a special button on the holder or torch body (for argon-arc welding), you can control the process.

An oscillator for welding, made by yourself or purchased in a store, is connected to the machine in order to, during the welding process, if necessary, generate a pulse that ignites an extinguished arc. As soon as the arc flares up, the impulse disappears. A short-term discharge is similar to a lightning strike; direct contact of the part with the electrode is not necessary for an arc to occur. The oscillator is suitable for work:

with tungsten non-consumable rod, filler wire;
standard coated electrodes (selected according to the type of workpiece being welded).

The pulses generated by the oscillator are short in duration, characterized by low duty cycle, with a power of up to 300 W. A spark breakdown is formed between the electrode and the part at a distance.

You can buy an oscillator from the factory or make it yourself

Self-made oscillators are no worse than factory ones in maintaining a stable arc during the welding process. The devices are triggered when the gap between the part and the electrode increases.

When the air gap is too large, the arc spontaneously extinguishes. The additional generator resumes combustion without the procedure of electrode striking or direct contact of the part with the electrode. Using your own hands, you can make an oscillator from existing electrical parts.

Before this, you need to know the criteria for selecting devices.

Varieties

Those who plan to assemble the oscillator themselves should select the type of welding equipment. The pulse device is used on devices of various types.

There are classifications of factory oscillators for inverters according to various criteria: dimensions, weight, technical characteristics: output voltage, frequency.

Continuous electrical appliances use direct current, and short-term discharge welding devices use alternating current. Depending on the operating mode, devices are connected in parallel or in series.

It is better to connect a device made by yourself in series, which reduces the risk of electric shock to the welder if the equipment malfunctions.

In the case of a series connection, one of the transformers is supplemented with a smoothing capacitor with a fuse, and the secondary is supplemented with an oscillating circuit connected to a spark gap.

Oscillator connection diagram

Devices for welding cyclic polarity are more often used for welding aluminum, as well as alloys based on it. Stainless steel and non-ferrous metals require direct current. When choosing devices, the characteristics of the workpieces, the type of welder available, and the amount of work to be done are taken into account. Once you have formed a habit of using your existing welding machine, you can expand the capabilities of the equipment yourself.

Source: https://svarkaprosto.ru/oborudovanie/ostsillyator-dlya-invertora-svoimi-rukami

Oscillator device for welding work

When working with electric arc welding machines, the electric arc is excited by contact between the electrode and the workpiece. It is not always possible to light an arc from the first touch.

Sometimes, to initiate an arc, touching must be replaced by repeated tapping to break through the non-conductive oxide layer on the surface of the workpiece.

Fine welding work with non-ferrous metals is carried out at low currents, which aggravate the instability of arc ignition. To solve problems of this kind, a so-called oscillator is used. It is used when welding in an argon environment, which is precisely applied to non-ferrous metals and alloys.

Device

Thus, the use of an oscillator for welding allows you to increase the stability of the welding machine and the quality of the work performed by providing the following capabilities:

remote ignition of an electric arc;
maintaining arc stability in case of random changes in the air gap size.

The main elements of the oscillator are: a transformer that increases the mains voltage of 220 Volts to 3 - 6 kV, an oscillatory circuit that generates high-frequency oscillations, and a spark gap.

Very often, oscillators are used in conjunction with argon arc welding machines, since these are the machines that work with non-ferrous metals. In this case, turning on the device is synchronized with the valve that opens the argon supply channels.

Connection

The connection diagram of the oscillator to the main welding machine depends on the design of the device. First of all, the oscillator must be connected to a 220 Volt power supply.

Connection to the welding machine can be of two types: parallel and serial. The figure below shows options for connecting the oscillator, as well as an example of the layout of the device, made in the form of a separate block.

When connected in parallel, the oscillator leads are connected to the welding electrode and the workpiece. In the serial version, the oscillator is connected to a section of the cable supplying the welding electrode.

You can find a large number of diagrams and descriptions of this useful device, using which it is easy to make it yourself. The device does not contain expensive or scarce parts and is accessible for use by a person with basic knowledge of electrical engineering .

Application

The main application of this device, as mentioned above, relates to welding of non-ferrous metals, although it is not limited to this area. The described device can be successfully used in combination with welding machines of any type.

Using an oscillator with a transformer for alternating current welding eliminates the disadvantages of this type of welding that cause unstable arc burning.

Moreover, in this option it becomes possible, in addition to standard electrodes, to use electrodes designed to work with direct current when welding.

This expands the technical capabilities of AC welding transformers and allows them to make welding joints that are not inferior in quality to those made by DC welding.

Using an oscillator to work with an inverter makes it possible to carry out welding work with lower current values, and therefore work with thinner and more delicate workpieces.

An oscillator designed for aluminum welding is often combined with a TIG welder. Aluminum is one of the most capricious non-ferrous metals that does not forgive the welder the slightest mistake.

It is prone to spattering and rapid burnout due to its low melting point. For this reason, it is for working with this metal that it is important to use technologies that allow working with low currents with high stability of the welding arc.

Circuit examples

If you want to make an oscillator yourself, then you should pay attention to the simplest circuits.

The diagram below shows a continuous operation device, so the connection to the network is carried out exclusively through a transformer. To assemble this circuit, you do not have to use expensive elements.

The disadvantage is the choice of thyristors. They need to be selected, as they say, at random, to try which thyristors produce the most stable welding arc.

The second circuit of a homemade oscillator for welding is also quite simple and does not have the disadvantages of the previous one. You can assemble a device using it with minimal skills in installing electrical circuits.

The third diagram shows the assembly elements in more detail.

When assembling, you must remember safety precautions, since the device operates with high currents.

Source: https://svaring.com/welding/prinadlezhnosti/oscilljator-dlja-svarki

Welding oscillator. Stabilization of the welding arc combustion

In everyday life it is often necessary to weld products made of non-ferrous metals, in particular aluminum and its alloys. At the same time, proper welding quality can only be ensured by stable arc burning. Without a welding converter and using only an inverter machine, it is difficult to achieve such quality. The solution is to use a welding oscillator, which stabilizes the arc and facilitates its ignition.

DIY welding oscillator

There are many industrial designs of welding oscillators. For example, the UVK-7 model, used to power DC and AC welding machines. The disadvantage of such a device is that it is unsuitable for an inverter, since it requires a power supply of no more than 80 V versus 220 V, from which welding inverters operate.

The OSSD-300 model is designed for an open circuit voltage of at least 60 V and will definitely require a ballast rheostat, which raises the bar for power requirements for the welding machine. Similar restrictions apply to the popular oscillator OP-240 “Ognivo”.

The initial data for making an oscillator with your own hands are:

Purpose (for aluminum or stainless steel).
The type of current used is alternating, direct and its voltage.
Power consumption is usually no more than 200-250 W, otherwise the cost of circuit components will increase sharply.
Secondary voltage, which must be no lower than 2500 V, otherwise making a homemade oscillator will not pay for itself.

It is easier to start work if you have a welding converter: in this case, the oscillator can be made not pulsed, but continuously operating, and connected to the welding network using a simpler serial circuit. Finally, at a high current frequency, the arc will be ignited without contact of the electrode with the surface to be welded, and stable arc burning is guaranteed even at relatively low current values.

The layout of the oscillator on a rectangular board is best done as follows. On the left is a high-frequency transformer, fuses and a control circuit, on the right is a choke, in the center is a spark gap, an oscillating circuit capacitor and a blocking capacitor, which will cut off the low-frequency current from the welding circuit.

The transformer is selected according to its required current characteristics in the secondary winding. It is more reliable to assemble a double inductor: when two oscillatory circuits are connected in series, the supply of current and voltage is more stable, and the protection of the oscillator from failure is more reliable. Both parts of the contours are identical and consist of:

a capacitor designed for less than double the voltage reserve (at least 450500 V for the first part and at least 4 kV for the second) with a capacitance of 0.3 mF (in the second stage it can be up to 1 mF);
a varistor with a voltage not less than that required for the voltage on the secondary winding - 90100 V (in the second stage it can be up to 140150 V);
an inductor, which is a ferrite rod onto which a wire with a cross-section of 1520 mm2 is wound with a gap of at least 0.8 mm. The number of turns in the first stage must be at least 7, in the second - less. The second coil serves as a kind of filter against possible current fluctuations of greater amplitude, which can lead to unstable arcing;

To manufacture the arrester, a board with stiffening ribs is selected, which should lower the temperature when triggered. As tungsten electrodes, you can use welding electrodes with a diameter of at least 2 mm. The ends of the electrodes are preliminarily trimmed so that they are strictly parallel. The gap must be adjusted using a screw.

To increase the stability of operation, a coil from any stun gun is connected to the secondary winding of the second stage. True, to power this coil, a voltage of 6V is required, which can only be obtained from a battery, but this is even better: a homemade oscillator still needs to be subjected to routine maintenance from time to time.

The first cascade is connected to the clamps of the welding inverter, and the second - to the part being welded and the welding torch. The oscillator should be assembled in a waterproof case, which is equipped with ventilation holes.

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Maintenance and operation of the welding oscillator

The fundamental rule is the safety and reliability of the oscillator. For this purpose it is necessary:

Periodically monitor the performance of the blocking capacitor, since otherwise the welder may be affected by the low-frequency component of the welding current.
All adjustments and settings should be performed when the device is disconnected from the power supply.
Regularly clean the spark gap electrodes from carbon deposits.
Check the frequency of the pulses that the oscillator produces: their frequency should be within 10..40 µs.

It should be remembered that the presence of a double oscillatory circuit in the welding oscillator is a source of quite strong interference in radio communications.

Source: https://proinstrumentinfo.ru/svarochnyj-ostsillyator-shema-svoimi-rukami-ossd-300/

Welding oscillator - device and DIY production

To facilitate the task of welding work with parts made of non-ferrous metals and stainless steel, it is necessary to use a welding oscillator. This useful device, which solves the problem of igniting the welding arc and maintaining it in a stable state, can be used equally successfully in production and at home.

Welding oscillator brand VSD-02, used to stabilize the arc

We understand the design and principle of operation of the oscillator

Welding oscillators, capable of working with AC and DC sources, are needed in order to simultaneously increase both the magnitude of the voltage and the frequency of the electrical current.

If the voltage at the input of such a device is 220 V and the current frequency is 50 Hz, then the output is already 2500–3000 V and 150,000–300,000 Hz. The duration of the pulses created by the oscillator is tens of microseconds.

The power of these devices, with the help of which high-frequency current and high voltage is supplied to the welding circuit, is 250–350 W.

The technical capabilities that the oscillator has are provided by its design and the characteristics of its elements.

The electrical circuit of the device consists of the following components:

an oscillatory circuit acting as a spark generator of damped oscillations (such a circuit includes a capacitor and an inductor - the moving winding of a high-frequency transformer);
arrester;
choke coils in the amount of two pieces;
step-up transformer;
high frequency transformer.

Functional diagram of the oscillator

In addition, the oscillator contains elements that ensure the safety of both the device itself and the welder. Such elements include a capacitor, which protects the welder from electric shock, and a fuse, which opens the electrical circuit if the capacitor breaks down.

The oscillator, which is used in conjunction with a welding machine, works according to the following principle. After passing through the windings of the step-up transformer, the voltage enters the capacitor of the oscillating circuit and begins to charge it.

When a capacitor is charged to the value provided by its capacitance, it discharges a discharge to the spark gap, which leads to breakdown. After this, the oscillatory circuit becomes short-circuited, which causes the occurrence of resonant damped oscillations.

The high-frequency current that forms these oscillations is supplied to the welding arc through a blocking capacitor and the coil winding.

An example of making an oscillator board

The blocking capacitor is designed in such a way that only high-frequency current, which also has a higher voltage value, can freely pass through it. Low-frequency current is not able to pass through such a capacitor due to too much resistance. Thanks to this characteristic of the blocking capacitor, low-frequency current from the welding machine cannot pass through it, which protects the oscillator from short circuits.

Types of welding oscillators

An oscillator, which, if desired, is easy to make with your own hands, can refer to:

continuous devices;
devices with pulse power.

Using oscillators of the first type, a high frequency current (150–250 kHz) and a high voltage value (3000–6000 V) is added to the welding current.

The ignition of such an arc can be carried out even without the electrode touching the surface of the workpieces being connected, and the arc burns very steadily even at low values of current supplied from the welding machine.

This is possible due to the high frequency of the current that the oscillator produces. What is important is that current with such characteristics is not dangerous for the welder performing work using this device.

Parallel and serial connection of the oscillator

The electrical circuit in which the first type of oscillator is involved may provide for its parallel or serial connection. Devices that are connected to the electrical circuit of the welding machine in series are more efficient. This is explained by the fact that their circuit does not use high voltage protection as unnecessary.

A welding oscillator with pulse power is required primarily when welding is performed on alternating current. In addition to the initial ignition of the welding arc, a device of this type provides its support when changing the polarity of the alternating current, which occurs constantly. Oscillators of the first type, under conditions of constant change in the polarity of alternating current, do not cope well with re-ignition of the arc, which negatively affects the quality of welding operations.

Oscillators, the electrical circuit of which contains capacitors that accumulate charge from a special charger, are also capable of contactless ignition of the welding arc.

At those moments when it is necessary to re-ignite the arc, these capacitors are discharged, and the electric current of their discharge is supplied to the arc gap.

The electrical circuit of such a welding oscillator contains a device that ensures synchronization of capacitor discharges at those moments when the electric arc current passes through zero.

As for the rules for using oscillators, it is necessary to take into account that welding of aluminum with their help is carried out using alternating current, and stainless steel - using direct current of direct polarity.

Rules for operating oscillators

The use of an oscillator for welding aluminum, other non-ferrous metals or stainless steel requires compliance with a number of simple rules that will make working with such a device comfortable and safe.

Oscillators can be used both indoors and outdoors.
It is not recommended to use welding oscillators outdoors if it is raining or snowing outside.
It is allowed to work with such devices at ambient temperatures from –10 to +40 degrees Celsius.
It is permissible to use oscillators at ambient humidity levels not exceeding 98%.
The atmospheric pressure at which such devices can be used must be in the range of 85–106 kilopascals.
It is not recommended to use such a device in rooms where the atmosphere is heavily polluted with dust, caustic vapors and gases that can destroy insulation and metal.
You can start working with the welding oscillator only if it is reliably grounded.
Before starting work, you should always check whether the device is correctly connected to the welding circuit and whether its contacts are working properly.
The oscillator casing must always be put on during welding work; it can only be removed when the device is disconnected from the electrical network.
The working surface of the spark gap must always be kept clean and free of carbon deposits. If carbon deposits appear, it must be removed using sandpaper.

You can not only buy such a device, which will help you weld non-ferrous metals and stainless steel, but also make it yourself.

How to make an oscillator device with your own hands

As mentioned above, oscillators allow you to ignite a welding arc without the electrode touching the surface of the parts being connected, and also maintain its stability during the combustion process.

This functionality of this device is ensured due to the fact that the electric current coming from the welding machine is superimposed on a current of high frequency and high voltage.

A device is used that can be made with your own hands, mainly for welding aluminum parts.

To make a homemade welding oscillator, you can use the simplest and most common circuit. The main element of the circuit of such a device is a transformer, which ensures an increase in the voltage value from the standard 220 to 3000 V. The main difficulty in making an oscillator with your own hands is the spark gap through which a powerful electric spark passes.

Homemade single spark gap

The most important element of the welding oscillator circuit is the oscillatory circuit, which must contain a blocking capacitor. Such a circuit, which also includes a spark gap and an inductor, solves the main task of the oscillator - generating damped high-frequency pulses that facilitate ignition of the welding arc and its maintenance in a stable state.

Both serial and hand-made, such a device can be made according to two main schemes: continuous and pulsed. Oscillators operating in a continuous circuit are considered less efficient; their design requires the use of devices that protect them from increased voltage. More effective are pulse oscillators, which ensure rapid ignition of the welding arc and its stable combustion when operating on alternating current.

Schematic diagram of a welding machine with an oscillator

When starting to make a homemade welding oscillator, you need to understand the electrical circuit of such a device and correctly select all the components, first of all, the high-voltage transformer.

The main control element of the oscillator is a button, which simultaneously turns on the spark gap and is responsible for supplying shielding gas to the welding area.

The high-frequency pulses themselves, which ensure the effective performance of welding work, are generated by a spark gap and a high-voltage transformer. The output elements of such a device are two contacts - positive and negative.

The first, supplied from a high-voltage transformer, is connected to the torch of the welding machine, the second - to the parts being welded.

In order to make such a device with your own hands, which greatly simplifies the process of welding parts made of non-ferrous metals and stainless steel, it is enough to have basic knowledge of electrical engineering and the skills of assembling electrical devices.

Of course, you can purchase such a device in a store or at the construction market, but it will cost you a lot. If you are going to use it not constantly, but from time to time, then it makes sense to make it yourself.

The most important thing to consider when assembling and using a homemade welding oscillator is the safety requirements when working with devices powered by electric current. As part of meeting such requirements, it is very important to strictly adhere to the correct assembly of electrical circuits, and also to use only those components that are optimally suited for their characteristics.

Source: http://met-all.org/oborudovanie/svarochnye/svarochnyj-oscillyator-svoimi-rukami.html

Oscillator for argon aluminum welding: connection diagram and DIY production

Non-ferrous metals and stainless steel are the control words during difficult thoughts like “I just didn’t have enough of an oscillator for complete happiness.” We declare with responsibility: you will not be completely happy with the arc if you weld stainless steel, aluminum or non-ferrous metals. Even with an inverter. Even with the right electrodes and serious welding experience.

The arc will let you down: either it is difficult to ignite, or it is unstable and has the ability to go out at the most inopportune time. And the tungsten electrode will also stick. Only one device will help cope with these troubles - an oscillator. So you can’t escape it anywhere. You'll have to buy it or make it yourself.

A good oscillator costs a lot of money, so if you do welding from time to time, it makes sense to understand its structure in order to make it yourself.

The principle of the design and operation of the oscillator

There are many schemes of such devices. But the set of fundamental blocks is the same.

How does argon welding with an oscillator work?

Here's what it includes:

Voltage boosting transformer: to convert the input mains voltage of 220 V and 60 Hz into higher frequency oscillations with a voltage value of up to 250 kHz of 56 kV.
Output transformer for transmitting current of increased voltage and frequency to the output contacts of the welding machine.
A spark-type generator with contacts in the form of tungsten electrodes, which is essentially a single-circuit spark gap.
Control unit consisting of a gas valve, stabilizer, start button and current sensor.
A special protective unit for monitoring excess current or voltage.

The device and circuit diagram of the device must be selected depending on the intensity of your work with its help. If your plans for welding work are dominated by aluminum, which needs to be welded at a constant current of reverse polarity, then we choose a series connection scheme - this will be an oscillator for welding aluminum.

If you are working with stainless steel, your circuit should be parallel connected.

The oscillator system for parallel welding is much more complex and requires two transformers. In the first of them, the primary winding consists of a double oscillating circuit, and the secondary winding includes a spark gap and is the primary winding of the second high-frequency type transformer.

It is from this that the electrical power of the arc is supplied. Such a circuit is not only difficult to assemble and regulate, it must be protected from voltages exceeding the maximum limits.

DIY oscillator

Despite the fact that welding oscillators of various models are offered on the market, you may need to build such a machine yourself. The implementation of such an idea is quite realistic; making this device with your own hands is not the easiest task, but it is also not a Newton binary.

First, make sure that you really need a DIY welding oscillator and that it is cost-effective.

Oscillator connection diagram.

Here are some factors that will help you with this:

You are going to cook stainless steel, aluminum or non-ferrous metals.
You are using DC or AC voltage.
The current power does not exceed 250 W.
The secondary voltage received must be equal to or greater than 2500 V.

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If you have a welding converter, the work will be much easier: your permanently operating machine will be connected to the welding network in series, which is much simpler. In addition, the arc will behave much better.

It will burn steadily and can be ignited without contact with the surface to be welded, regardless of the current strength.

The current characteristics required in the second winding will help you select the optimal transformer. The inductor should be double - it’s more reliable. If you have two oscillating circuits connected in series, the current and voltage will be stable.

Electrical diagram of the device.

The oscillatory circuits must be identical and must consist of the following components:

capacitor;
voltage varistor;
inductors made of ferrite rod.

The arrester requires a special rigid board, since when triggered the temperature must drop. Tungsten electrodes must be at least 2 mm in diameter, they must be placed strictly parallel, for this they are trimmed. The width of the gap between them is adjusted with a screw.

We connect the first cascade to the inverter terminals, and the second cascade to the welding torch and the workpiece being welded. For high stability of operation, a coil with separate power supply from the battery must be connected to the secondary winding of the second stage.

A mandatory requirement is that the housing must be resistant to moisture, and with special holes for ventilation.

Rules for using a homemade oscillator

It is clear that the main requirements are the safety and reliability of the device.

Schematic diagram of the oscillator.

To comply with them you need:

Check the operation of the blocking capacitor on a regular basis. If it is not in order, you may be injured by low frequency welding current.
Make it a rule to adjust and configure the device only when it is disconnected from the network.
Clean carbon deposits from the electrodes, do this constantly.
The pulse frequency from the oscillator should not exceed 40 µs: keep an eye on this.

An oscillator for DIY welding is a very smart technological addition to your welding equipment if you are welding specific metals: stainless steel and aluminum. You can buy an oscillator, or you can make it yourself. This requires a clear head, good hands and our advice.

We wish you reliable capacitors, parallel electrodes and high-quality windings in your transformers. And good orders!

Source: https://tutsvarka.ru/oborudovanie/ostsillyator

Operating principle of welding oscillator

When it is necessary to weld a crack or assemble a structure made of high-alloy steel, coated electrodes with the appropriate composition and a direct current source are used. Stainless steel and tungsten electrodes lend themselves well to welding. To connect aluminum parts, the same means are used, only using alternating current.

But in each case a difficulty arises - igniting the arc. Such metals are coated with an oxide film, which prevents contact between the surface and the electrode. To solve this problem, an oscillator is added to the equipment circuit. It promotes rapid initiation of the welding arc and maintains its combustion.

What is an oscillator in detail? What types of such devices are there, and on what principle do they work?

What it is

A welding oscillator is a generator used to generate a high frequency current that connects the end of the electrode and the surface being welded without physical contact. Such equipment is installed between the welding machine and the holder. There are separate devices that are included in the body of the welder itself. Such devices can operate according to two schemes:

Create a short-term impulse that helps initiate the arc without touching the product. Visually, it looks like a small “lightning” sent from the end of the electrode to the surface to be welded. When the latter is reached, and there is a pre-connected mass on the product, contact is established and the seam becomes possible. The pulse itself fades after ignition of the arc.
Maintain a constant voltage with a high V value, which is superimposed on the welding current. This allows you to simultaneously weld and maintain arc stability.

Using Oscillators

Due to their properties, welding oscillators are widely used in equipment for working with non-ferrous metals. When it is necessary to make a seam on stainless steel, aluminum, or copper, the use of an oscillator allows you to quickly excite the arc and begin welding, instead of tedious tapping and striking the electrode on the workpiece.

It is also convenient to use this device to accurately start a seam. The welder places the end of the tungsten needle on the near edge of the joint, lowers the mask, and presses the button to initiate the arc. This significantly reduces subsequent processing of the product from traces of contact with the electrode. They are also being used on plasma cutting machines, allowing you to quickly begin the process of cutting the material.

The welding oscillator is also used for working with thin sheets of metal. As a rule, the inverter current in such cases is set to low values, and the slightest removal of the end of the electrode from the weld pool leads to interruption of the arc. The introduction of an oscillator into the circuit makes it possible to stabilize electric welding when operating at low currents.

Oscillator device

Such devices are always integrated into the equipment circuit between the transformer or rectifier and the welding electrode holder. As a result, contact is established and work is stabilized. Most oscillators have a similar structure and include the following components:

voltage rectifier;
charge storage unit made of capacitors;
power supply;
unit for generating a pulse, with an oscillatory circuit and a spark gap;
Control block;
gas valve (in argon installations);
step-up transformer;
voltage sensor

Why does a welder need an oscillator, how does it work

When working with electric arc welding, you need to have a certain skill. It will be required not only when forming a seam, but also at the initial stage, when the process of igniting the arc occurs.

In the classical concept, an arc occurs as a result of contact of an electrode with a metal surface. For 1 cm of air to become a conductor, it is necessary to apply a potential difference of approximately 30 thousand volts.

Naturally, this voltage is too high even for modern inverters, so the only way to ignite the arc is through contact with the gradual removal of the electrode.

The result of such manipulation directly depends on the skill of the welder, however, even professionals do not guarantee that a stable arc will form after the first contact.

Often the welder makes oscillatory movements with the holder, while tapping on the surface of the part in order to break the oxide layer. Such difficulties arise especially clearly when working with non-ferrous metals. If we take into account the fact that according to the regulations, welding of non-ferrous metals is carried out with low currents, then the likelihood of obtaining a stable arc is sharply reduced.

A device better known as a welding oscillator helps to avoid such problems. It acts as additional equipment to the power source when conducting argon arc welding. To use it, the master must have a sufficient amount of knowledge, starting from the device and ending with the connection method.

Operating principle and purpose

The use of an oscillator allows for non-contact ignition of the arc, which greatly facilitates the welder’s task and also affects the stability of the electric arc during operation.

Although we noted that the device is a separate element, sometimes it is integrated into the welding inverter, that is, the power source and oscillator are in the same housing. With a sufficient amount of knowledge in the field of electronics and electricity, it is possible to make a homemade oscillator.

This is where readers usually focus their attention, since saving money always looks attractive.

Let's start by formulating the basic idea of how this device works. When the welding inverter is operating, a voltage of 220 V is supplied to the electrodes. If welding is carried out with alternating current, then its frequency is 50 Hz. “On top” of this voltage, a high potential difference and high frequency are applied in pulse mode.

The number of such impulses is usually small. The additional high-frequency current should only ignite the arc. This takes a split second. For a qualitative assessment, it should be emphasized that the amplitude of voltage fluctuations reaches 6 kV, and the frequency is 500 kHz.

But due to the short pulse duration, the electric current power does not exceed 300 W.

A laconic question arises among users: “Can an oscillator weld metals using the generated current?”

Indeed, this would be logical, but the low power does not allow the metal and additive to melt, so the pulse is used exclusively to break down the air gap. The welder’s task is only to approach the electrode to a distance of approximately 5 mm and press the button.

In integrated type oscillators, the button is located directly on the holder. The pulse duration corresponds to the time the button is held. Next, welding is carried out as usual.

High frequency current flows through the dielectric (air) after active ionization. An arc discharge occurs almost instantly. At the same time, the ionized air becomes a conductor, and the main current of the welding machine flows, forming an electric arc.

If the welding process is automated and the inverter has a microprocessor, then the oscillator in the process of forming a seam is automatically turned on if necessary, when there is a tendency to extinguish the arc. An example would be a situation with a voltage drop or accidental movement of the welder’s hand to the side.

As a result of the operation of the oscillator, you can obtain a high-quality and uniform seam.

Design and operation

While it is not so difficult to understand the purpose of the oscillator, understanding its operation will require some knowledge of physics. The first thing you need to understand is that with the help of this device we get remote ignition of the arc and, during the welding process, a stable arc that is static with respect to the changing gap between the electrode and the metal surface.

The oscillator fundamentally consists of several blocks:

The step-up transformer is used to convert the voltage amplitude.
An oscillatory circuit with a classical structure. It consists of a capacitor and an inductor. High-frequency oscillations occur in this circuit.
Arrester. Its main element is the air gap in which the spark occurs.

Naturally, we have not taken into account various sensors that provide autonomy and control systems. When implementing an integrated circuit, when the oscillator is an integral part of an argon-arc inverter, the device is equipped with a gas supply valve.

The latter is controlled by a microprocessor and supplies argon at the right time. The oscillator is equipped with a safety system that ensures uninterrupted operation of the electrical circuit, as well as the safety of the life and health of the welder. A capacitor protects against electric shock.

In the event of a breakdown, a fuse comes into operation, opening the circuit when the current is exceeded.

The oscillator operating algorithm can be represented as a sequence of processes. The operating voltage of the household network is supplied to the primary winding of the step-up transformer. After converting the current, an EMF of a given value (5-6 thousand volts) is induced on the secondary winding. At the moment, the current frequency is equal to the industrial frequency, that is, 50 Hz.

An oscillating circuit capacitor is connected to the winding of the secondary coil. It begins to charge, but since the natural frequency of the oscillatory circuit exceeds the frequency of the current on the winding, oscillations occur in the circuit. Initially, the circuit is open, but the breakdown in the spark gap plays the role of a kind of key and closes the circuit.

Current fluctuations in the circuit flow to the electrode.

One of the remarkable properties of a capacitor is the transmission of alternating electric current. Capacitance decreases with increasing frequency. The blocking capacitor blocks the low-frequency current that feeds the inverter itself, but allows high-frequency current to pass through. This protects the oscillator from short circuits.

Types, connection

Based on the principle of operation, devices are divided into two types:

Continuous oscillators.
Pulse oscillators.

When the first type of oscillator operates, the welding current is summed with a high-frequency high-voltage current. The arc is ignited without direct contact of the electrode with the metal surface. At low current values, the arc remains stable.

Metal splashing and electric discharge damage to the welder are eliminated. Such an oscillator can be connected to the network in series or in parallel. When connected in series, the device is connected to the break in the electrode cable. This connection allows you to use the oscillator in a more efficient way.

There is no energy loss to provide high voltage protection.

The pulse oscillator is connected in parallel and is used mainly in cases where it is necessary to carry out welding work with alternating current. The whole difficulty lies in the fact that the device must respond to a change in polarity, and in a minimum time.

Only high-frequency pulsed current can support the arc, increasing its stability.

If you use continuous-action machines for such welding, then the arc will be obtained without any problems, but its re-ignition is no longer possible, that is, the oscillator will perform only one of its functions.

The presence of capacitors in the circuit allows you to make a more functional device. The accumulated electric charge makes it possible to produce repeated impulses and ignite the arc during the formation of a seam, if the welder accidentally deflects the electrode over a long distance. In a device circuit you cannot do without feedback. It is the control system that ensures synchronized discharge of the capacitor.

Source: https://svarkoy.ru/oborudovanie/oscillyator.html

Application of an oscillator for welding

If it is necessary to weld seams with defects or weld metal structures made of steel, welders use coated electrodes and an inverter that produces direct current. Tungsten electrodes are also often used in welding stainless steel. Regardless of the chosen electrode or welder model, the problem of correct and quick ignition of the arc often arises. To solve this problem, just connect a welding oscillator to the equipment chain.

In this article we will tell you what an oscillator is in combination with other welding equipment, what the principle of operation is and how to use it in your work.

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general information

A welding oscillator for welding aluminum or any other metal is a device that generates high frequency current. Thanks to this current, the electrode interacts better with the metal surface. To use the oscillator you need a welding machine and an electrode holder. In this case, the oscillator is installed between them. The most famous oscillator models: OSSD 300 and OSSD 400, OP 240, OP 400.

In general, such devices operate on the following principle: the oscillator generates a short-term electrical pulse, igniting an arc. The pulse disappears immediately after ignition of the arc. In this case, there is no need for physical contact between the electrode and the metal surface. From the outside, this impulse looks like a small lightning bolt between the end of the electrode and the surface to be welded. By the way, you can make an oscillator yourself.

Peculiarities

There are several types of oscillators and they are all used for specific tasks. But we'll start with the characteristics that all types of oscillators have in common. So, all devices are capable of converting current up to 5000V and increasing the frequency up to 500 kHz.

Now about the differences. There is an oscillator for welding aluminum or any other metal that runs continuously. Thanks to continuous action, a stable arc is ensured. Most modern devices sold in stores belong to this type.

This type of oscillator should be connected in series to avoid excessive voltage that could cause you harm. Remember to follow safety precautions in the workplace. With the help of such devices, you can weld using a low current value and easily ignite the arc.

Often such an oscillator is installed on a welding inverter or transformer to work with coated electrodes.

There are also oscillators for non-contact excitation of the arc when welding using argon machines. They differ in that they have a gas valve. Typically, argon welding is performed using tungsten electrodes, which can often become dull when ignited using the tapping method. Because of this, the seam turns out to be sloppy and uneven, and the arc burns unstable. You can, of course, continually sharpen the electrode, but we still recommend using an oscillator.

Instead of a conclusion

Welding with an oscillator (for example, with the OSSD 300 or OP 240 model) simplifies and speeds up welding work, saving consumables. There is no need to worry about arc stability or how quickly to light it. Special craftsmen can make an oscillator with their own hands. Try the welding oscillator and share your experience in the comments to our article. Good luck!

Source: https://svarkaed.ru/oborudovanie-dlya-svarki/detali-i-prisposobleniya/primenenie-ostsillyatora-dlya-svarki.html

Do-it-yourself oscillator for welding: what it is and what it’s used for, diagram, video

Welding is stabilized, a uniform seam is formed, and the risk of sticking during a drop-by-drop short circuit is reduced when using consumable electrodes.

Why do you need a homemade oscillator?

The oscillator as a generating device is capable of operating on direct and alternating current. The purpose of the device is to excite the welding arc without contact of the electrode with the welding object and stabilize combustion. The type of electrode: tungsten torch tip or standard coated tip does not matter. The effect is achieved by transforming the mains current into high-voltage frequency pulses, with the following parameters:

Mains voltage 220 V - output voltage - 2.5–3 thousand V;
Current frequency 50 Hz - output frequency - 15–30 thousand Hz;
Oscillator power – 250–400 W.

Electrical circuit of the oscillator

The operating principle of a homemade oscillator included in the welding device circuit with a degree of simplification:

Supplying mains voltage to the welding device;
The voltage passes through the windings of the step-up transformer and begins to charge the capacitor of the oscillating circuit;
The storage capacitor accumulates the high-frequency high-voltage discharge voltage;
In parallel, the system control unit opens the gas valve;
The control unit releases a pulse when the capacitor capacity is filled onto the spark gap, a breakdown occurs;
The oscillatory circuit is short-circuited, and resonant damped oscillations occur that go to the welding arc;
When a capacitor breaks down, the fuse opens the electrical circuit;
When the voltage drops, the next discharge is formed;
The arc flashes in a gas cloud 3–5 mm above the part;
When the remote contact breaks, the control circuit duplicates the arc ignition pulse.

Functional diagram of the oscillator

DIY welding oscillator - components

There are a lot of schematic diagrams of oscillators for a welding device on the Internet. Both types are presented: serial and parallel connections. Lots of arguments in favor of each. Assembling the oscillator is half the battle. Difficulties await during setup and operation.

The device consists of several blocks. The oscillatory circuit as a spark generator of damped oscillations consists of 2 elements: a capacitor and a moving winding of a high-frequency transformer - an inductor.

DIY oscillator device

The step-up transformer of the device is assembled on the basis of a step-down transformer from 220 to 36 V, with a U-shaped core. To create a long magnetic line, 50% of the iron package is removed. The winding of the first core is wound like a welding one - we get a falling characteristic.

The step-up winding of the second core is designed to produce 1000 V. The lack of turns will force the spark gap to be constantly wound. Increasing the number of turns will lead to improved arc ignition in the spark gap. Overwinding leads to increased overheating of the coil.

Chokes 2 pcs. in a parallel circuit, 1 per transformer.

Manufacturing a spark gap from thickened, erosion-resistant WR-3 tungsten rods on copper rods requires the use of an adjustment mechanism. The optimum gap on the feeler gauge is 0.08 mm. Requires filling with a fast-hardening dielectric. To simplify things, spark plugs and air ionizers are used.

The output transformer is connected by a feedback line to the current sensor.

Source: https://instanko.ru/elektroinstrument/oscillyator-eto.html

Oscillator for welding: principle of operation, application, characteristics, how to choose the right one

When craftsmen need to weld joints that are not ideal, have corrosion deposits or, for example, large steel structures, they use electrodes that have a shell and a direct current apparatus.

There are also tungsten electrodes in use, for example, for welding steel, which is not subject to rusting.

But the greatest number of questions arise about how to make your arc stable; this is no longer affected by the type of electrode.

To solve this eternal problem for welders, an oscillator was invented, you just need to connect it to all the other elements of the chain, and you can start a comfortable, uninterrupted robot.

Our article will tell you how this device works when connected to a welding machine circuit, all its characteristics, and brief recommendations for use.

Introductory part

How to create a current of sufficient strength when we weld types of metals such as aluminum and others - an oscillator is designed for this. It is the high voltage that allows the electrode to connect well with types of metals.

But it all starts with a typical welding machine and an electrode holder, then an oscillator can be added to this chain. It should be located between the electrode holder and the welding machine itself.

The most popular models are OSSD300, OSSD400, also OP400, OP240.

The general operating principle of such devices is that the device creates a pulse of electricity, which in turn ignites the welding arc. Once the arc is formed the pulse stops.

Under such conditions, there is absolutely no need for the metal and the electrode itself to come into contact. Such an impulse is similar to a small lightning bolt that appears between the metals and the electrode. What’s also very nice is that you can build the oscillator yourself.

Organization

The most standard type of oscillator that is presented on store shelves is a device made of capacitors that save energy and a rectifier.

The kit also includes a power supply unit, an independent unit, which is responsible for the formation of an electricity pulse with a spark gap and an oscillating circuit, this also includes a control panel, and sensors that indicate an increase in the fall in the transformer.

The main thing about the operation of the oscillator

The task of such a device is not only that it forms a current pulse, but it also changes the voltage that enters, the voltage becomes higher and the volts then increase.

It only takes a few microseconds and you get the result. Let's talk in more depth about how it works. It all starts with the fact that you need to put the entire system into the robot; for this there is a welding torch button.

Then the rectifier comes into force, it makes the current uniform, then the entire current changes direction to the same direction for everything. Next, capacitors collect this current.

Next, the current is released and sent to the oscillatory circuit. At this stage the volts rise. But it is also possible that the gas valve opens if you are welding with argon.

Again, an impulse appears, which is so similar to a small lightning bolt. It combines the electrode and the metal and then the welding process occurs. BUT do not forget to attach the ground cable to the surface first.

The setup is complete. Your machine is fully connected and ready for welding. And a constant arc is guaranteed to you by the oscillator models (OSSD300, OP240 or OP400).

Special Features

There is also a small specialized range of welding oscillators, so you can find one for a variety of tasks. But of course they have a lot in common, generic features, so to speak.

Let's start each oscillator can handle current up to 5000 Watts and increase the frequency up to 500 kHz.

But they all differ in certain features; there are special oscillators for working with aluminum or other metals that require continuous operation.

It is this characteristic that guarantees stability. AT the moment this is the most popular type, its share in stores is the largest, it is the most versatile and practical.

But this type of oscillator may not be safe for you if you are a beginner and do not connect it correctly to the overall system; if you connect it without a certain sequence, a voltage surge will occur.

Remember that your life is the most precious thing you have, so it’s better to spend the extra 2 minutes on the correct connection.

Such a device allows you to easily create a stable arc even at a low current value.

Most often, oscillators are adapted to welding equipment or to a transformer if there is a robot with coated electrodes.

There are also devices for non-contact arc production; its use is widespread when working with argon devices. Their design is slightly different; they have a gas valve.

The most commonly used material for this type of welding is tungsten electrodes; they cannot be used without contact, because they begin to become dull from light impacts on the metal.

This significantly reduces the quality of the seam; it may turn out unsightly, crooked, and the arc will constantly go out.

Of course, you can always sharpen the electrode and it will be sharp again, but no one wants to do this routinely, so the best choice for this type of welding is an oscillator.

Usage

We all know how you unsuccessfully tap an electrode on that ill-fated gate, and the result, to put it mildly, is not ideal, this is typical behavior of beginners who try to light an arc using such a violent method, and this often takes a lot of time and effort.

It’s enough to torture yourself, the oscillator was specially designed to ensure that the welding arc is always stable and welds non-ferrous metals well.

You can easily create neat, strong joints, even on aluminum surfaces or stainless steel fragments.

The oscillator will also allow you to comfortably engage in plasma cutting. It is ideal for welding difficult areas and thin metal.

Just don't turn on a very strong current and connect an oscillator, the result should not be bad. The arc will be stable even at low power, and this is very useful when you need to weld a long section, especially in a visible place

Bottom line

Oscillator models (OSSD300 or OP240) will simplify the welding process many times over, make it cheaper and faster. Your welding arc will not be interrupted and go out in seconds, when you haven’t even had time to do anything yet.

After all, this is the biggest and most unpleasant problem when working with a welding robot: the arc constantly goes out and the work you planned to do in half an hour stretches out for hours.

The quality of the weld seam is also significantly reduced, and there are sagging or simply unwelded areas that cannot last for a long time. Real masters even learned how to make such a device themselves, but this is definitely not for beginners.

Try the oscillator in operation and share with us your experience and operating features. Write comments, share articles. Good luck to everyone!

Source: https://prosvarku.info/prisposobleniya-i-detali/oscillyator-dlya-svarki