To facilitate the task of welding with parts of non-ferrous metals and stainless steel, it is necessary to use a welding oscillator. This is a useful device, the crucial task of ignition of the welding arc and its maintenance in a stable condition, can be used equally successfully in production, and in everyday life.
Welding oscillator of the VSD brand-02, which is used to stabilize the combustion of the arc
We understand the design and principle of operation of the oscillator
Welding oscillators, able to work with AC and DC sources, necessary for that, to simultaneously increase both the magnitude of the voltage, and the frequency of electric current. If the input voltage of such a device is 220 V, and current frequency - 50 Hz, then the output is already out 2500-3000 In and 150000-300000 Hz. Pulse duration, which creates an oscillator, is tens of microseconds. The power of these devices, by means of which in a welding chain current of high frequency and with big value of pressure arrives, — 250-350 W.
Technical capabilities, which has an oscillator, provided by its design and characteristics of its elements.
The electrical circuit of the device consists of the following components:
- oscillating circuit, which acts as a spark generator of attenuating oscillations (such a circuit includes a capacitor and an inductor - a moving winding of a high-frequency transformer);
- spark gap;
- throttle coils in the amount of two pieces;
- step-up transformer;
- high frequency transformer.
Functional diagram of the oscillator
in addition, the oscillator contains elements, ensuring security as the device itself, and the welder. Such elements include a capacitor, which protects the welder from electric shock, and fuse, which opens the electrical circuit when the capacitor breaks down.
Oscillator, which is used in conjunction with a welding machine, works on 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 the capacitor is charged to the value, provided by its capacity, it issues a discharge to the arrester, which leads to breakdown. After that, the oscillating circuit is shortened, which causes resonant damping oscillations. High frequency current, which forms these oscillations, through the blocking capacitor and the coil winding enters the welding arc.
An example of making an oscillator board
The blocking capacitor is arranged as follows, that only high frequency current can pass freely through it, which is characterized by a large value of voltage. Low-frequency current through such a capacitor is not able to pass due to too much resistance. Due to this characteristic of the blocking capacitor, low-frequency current from the welding machine cannot pass through it., which protects the oscillator from short circuit.
Types of welding oscillators
Oscillator, which, if desired, is easy to do with your own hands, may refer to:
- continuous devices;
- devices with switching power supply.
With the help of oscillators of the first type, high frequency current is added to the welding current (150-250 kHz) and with a high voltage value (3000-6000 V). Ignition of such an arc can be carried out even without touching the electrode to the surface of the connected workpieces, and the arc burns very steadily even at small current values, coming from the welding machine. This is possible due to the high frequency of the current, which emits an oscillator. What is important, current with such characteristics is not dangerous for the welder, involved in the work using this device.
Parallel and series connection of the oscillator
Electrical circuit, in which the oscillator of the first type is involved, may involve its parallel or series connection. Devices are more efficient, which are connected to the electrical circuit of the welding machine in series. This is due to the fact, that in their scheme do not apply due to unnecessary protection against high voltage.
Pulse-powered welding oscillator is required mainly for welding, which 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 alternating current, which occurs constantly. Oscillators of the first type in the conditions of constant change of polarity of alternating current badly cope with repeated ignition of an arc, which negatively affects the quality of welding operations.
Oscillators are also capable of contactless ignition of the welding arc, in the electrical circuit of which there are capacitors, which accumulate charge from a special charger. In those moments, when it is necessary to re-ignite the arc, these capacitors are discharged, and the electric current of their discharge is fed into the arc gap. The electrical circuit of such a welding oscillator includes a device, which provides synchronization of capacitor discharges at those times, when the electric current of the arc passes through zero.
As for the rules of use of oscillators, must be taken into account, that welding of aluminum with their help is performed on alternating current, and stainless steel - at a direct current of direct polarity.
Rules of operation of oscillators
The use of an oscillator for welding aluminum, other non-ferrous metals or stainless steel requires a number of simple rules, which will make working with such a device comfortable and safe.
- Oscillators can be used both indoors, and beyond.
- The use of outdoor welding oscillators is not recommended, if it is raining or snowing outside.
- It is allowed to work with such devices at ambient temperature from -10 to +40 degrees Celsius.
- It is permissible to use oscillators at the level of ambient humidity, not exceeding 98%.
- Atmospheric pressure, in which you can use such devices, should be in the interval 85-106 kilopascals.
- It is not recommended to use such a device indoors, whose atmosphere is heavily polluted with dust, caustic vapors and gases, which can destroy insulation and metal.
- It is possible to start work with the welding oscillator only in that case, if it is securely grounded.
- Always check before starting work, whether the device is properly connected to the welding circuit and its contacts are working.
- The oscillator cover must always be put on during welding, it can be removed only then, when the device is unplugged.
- The working surface of the arrester must always be kept clean, there should be no traces of soot on it. In case of scale, it is necessary to get rid of it with the help of sanding skin.
Such a device, which will help you perform welding of non-ferrous metals and stainless steel, you can not only buy, but also do it with your own hands.
How to make an oscillator with your own hands
As mentioned above, oscillators allow to ignite a welding arc without touching an electrode of a surface of details, connecting, and maintain its stability during combustion. This functionality of this device is provided due to the fact, that on electric current, coming from the welding machine, current is applied, having a high frequency and high voltage value. The following device is used, which can be done with your own hands, mainly for welding aluminum parts.
To make a homemade welding oscillator, you can use the simplest and most common scheme. The main element of the circuit of such a device is a transformer, which provides an increase in voltage from standard 220 to 3000 V. The main difficulty in making an oscillator with your own hands is the arrester, through which a powerful electric spark passes.
Homemade single-spark arrester
The most important element of the welding oscillator circuit is the oscillating circuit, in which a blocking capacitor must be present. Such a contour, which also includes an arrester and an inductor, solves the main problem of the oscillator - generating fading high-frequency pulses, facilitating the ignition of the welding arc and its maintenance in a stable state.
As serial, and made with his own hands, such a device can be made according to two main schemes: continuous and pulsed action. Oscillator, operating on a continuous basis, considered less effective, devices must be used in their design, protecting them from high voltage. Pulse oscillators are more efficient, which provide rapid ignition of the welding arc and its stable combustion when working on alternating current.
Schematic diagram of a welding machine with an oscillator
Starting to make a homemade welding oscillator, it is necessary to understand the electrical circuit of such a device and correctly select all the components, in the first place, high voltage transformer.
The main control of the oscillator is the button, which simultaneously includes the arrester and is responsible for supplying shielding gas to the area of welding. The most high-frequency pulses, providing effective performance of welding works, produce arrester and high-voltage transformer. The output elements of such a device are two contacts - positive and negative. First, supplied from a high-voltage transformer, connects to the torch of the welding machine, the second - to the welded parts.
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 skills of assembling electrical devices.
Of course, you can buy such a device in a store or on the construction market, but it will not be cheap for you. If you are going to use it you are not constantly, and from time to time, it makes sense to make it with your own hands.
The most important thing, what to consider when assembling and using a homemade welding oscillator - these are the safety requirements when working with devices, powered by electricity. In compliance with such requirements, it is very important to strictly adhere to the correctness of the wiring diagrams, and use only those components, which are optimal for their characteristics.