How to select the current for an electrode - Metals and their processing

Transformer no-load mode

One of the most used electrical devices is the transformer. This equipment is used to change the magnitude of electrical voltage. Let's consider the features of the transformer no-load mode, taking into account the rules for determining characteristics for various types of devices.

The transformer consists of primary and secondary windings located on the core. When voltage is applied to the input coil, a magnetic field is formed, inducing a current in the output winding. The difference in characteristics is achieved due to the different number of turns in the input and output coils.

Transformer operating principle

What is idle mode

The idle mode is understood as the state of the device in which, when an alternating current is supplied to the input coil, the output coil is in an open state. This situation is typical for a unit connected to the mains, provided that the load to the output circuit has not yet been turned on.

Short circuit mode

How is the idle test performed?

When conducting an idle test, it becomes possible to determine the following characteristics of the unit:

transformation ratio;
power loss in steel;
parameters of the magnetizing branch in the equivalent circuit.

For the experiment, a rated load is applied to the device.

When conducting an idle test and calculating characteristics based on this technique, it is necessary to take into account the type of device.

In this state, the transformer has zero useful power due to the absence of electric current at the output coil. The applied load is converted into heat loss on the input coil I02×r1 and magnetic core loss Pm. Due to the insignificance of heat losses at the input, they are not taken into account in most cases. Therefore, the total value of no-load losses is determined by the magnetic component.

Also read: Why is the transformer humming?

The following are the features of calculating characteristics for various types of transformers.

For single phase transformer

The no-load test for a single-phase transformer is carried out with the connection:

voltmeters on the primary and secondary coils;
wattmeter on the primary winding;
ammeter at the input.

The devices are connected according to the following scheme:

To determine the no-load current Iо, use an ammeter reading. It is compared with the rated current value using the following formula, resulting in a percentage:

Iо% = I0×100/I10.

To determine the transformation ratio k, determine the value of the rated voltage U1н according to the readings of the voltmeter V1 connected to the input. Then, using the voltmeter V2 at the output, the value of the rated voltage U2O is taken.

The coefficient is calculated using the formula:

K = w1/w2 = U1н/ U2О.

The amount of loss is the sum of the electrical and magnetic components:

P0 = I02×r1 + I02×r0.

But, if we neglect electrical losses, the first part of the sum can be excluded from the formula. However, an insignificant amount of electrical losses is typical only for low-power equipment. Therefore, when calculating the characteristics of powerful units, this part of the formula should be taken into account.

No-load losses for transformers with a power of 30-2500 kVA

For three-phase transformer

Three-phase units are tested according to a similar scheme. But the voltage is supplied separately for each phase, with the appropriate installation of voltmeters. You will need 6 units of them. You can conduct an experiment with one device, connecting it to the required points one by one.

When the rated voltage of the winding electric current is more than 6 kV, 380 V is supplied for testing. The high-voltage mode for conducting the experiment will not allow achieving the necessary accuracy for determining the indicators. In addition to accuracy, the low-voltage mode ensures safety.

The following scheme applies:

The operation of the device in idle mode is determined by its magnetic system. If we are talking about a type of device similar to a single-phase transformer or an armored rod system, the closure of the third harmonic component for each phase will occur separately, with a value increasing to 20 percent of the active magnetic flux.

As a result, an additional EMF arises with a fairly high rate - up to 60 percent of the main one. There is a danger of damage to the insulating layer of the coating with the possibility of failure of the device.

It is preferable to use a three-rod system, when one of the components will not pass through the core, with a circuit through air or another medium (for example, oil), with low magnetic permeability. In such a situation, the development of a large additional EMF, leading to serious distortions, will not occur.

For welding transformer

For welding transformers, idling is one of the modes of their constant use in operation. During welding in operating mode, the second winding is short-circuited between the electrode and the metal of the part. As a result, the edges melt and a permanent connection is formed.

After finishing work, the electrical circuit is broken and the unit goes into idle mode. If the secondary circuit is open, the voltage in it corresponds to the EMF value. This component of the power flow is separated from the main one and is closed through the air.

To avoid danger to humans when the machine is idling, the voltage value should not exceed 46 V. Considering that in some models the value of these characteristics exceeds the specified value, reaching 70 V, the welding unit is equipped with a built-in performance limiter for idle mode.

The blocking is activated within a time not exceeding 1 second from the moment the operating mode is interrupted. An additional protective measure is a grounding device for the welding unit housing.

Measures to reduce no-load current

The current when the transformer is in idle mode occurs due to the design features of the core. A ferromagnetic material exposed to an alternating current electric field is characterized by the induction of eddy inductive Foucault currents, which cause heating of the element.

To reduce eddy currents, the core is not made as a single piece, but is assembled from a package of thin plates. The plates are insulated from each other. An additional measure is to change the properties of the material itself, which makes it possible to increase the threshold of magnetic saturation.

Welding electrodes: which ones are best for an inverter?

Many novice welders are wondering which electrodes for an inverter are best to choose. After all, this equipment is most often used by home craftsmen. In general, welding inverters have replaced transformer units that were used before quite a long time ago. This is due to the fact that the inverter is easy to operate, inexpensive, and in addition, it can be used to weld metal parts and structures quite quickly.

Such equipment is usually used in fusion arc welding. Inverters are characterized by constant stability and welding current, which ensures a super-strong connection due to the high quality of the seam.

The electrode plays the role of one of the main components of the described welding. These are metal rods that are necessary to supply current to the welding zone. In this case, it should be taken into account that welding units come in different types.

Therefore, they require different electrodes.

Which electrodes to choose

If you, too, were among those who wondered about which electrodes are best for an inverter, then you should read the information presented below. Consumable-type electrodes used in inverter and in general arc welding are made from welding wire, in the process of which state standards of 1970 are used.

According to GOST 2246, electrodes for inverter welding are classified into:

alloyed;
carbon;
highly alloyed.

The first ones are made from the following types of wire:

Sv-08Х3Г2СМ.
Sv-08HN2GMTA.
SV-08KhGSMFA.

When deciding which electrodes are best for inverter welding, you should become more familiar with carbon rods, which are made from wire Sv-08 and Sv-08AA, etc. High-alloy electrodes are based on wire Sv-30Х25Н16Г7 and Sv-01Х23Н28М3Д3Т. However, none of these lists can be called complete. The rod is coated by pressing. It protects the weld pool from atmospheric influences and allows the arc to burn more steadily.

Beginners should know that electrodes can be classified into two subgroups. The first provides products intended for making seams when connecting critical metal structures. The second subgroup is intended for work with conventional connections.

For critical products, it is best to prefer UONI or ANO electrodes.

If you are faced with the question of which electrodes are best for an inverter, then you should also pay attention to products marked MP-3, which are intended for conventional welded joints. The SSSI brand of electrodes is quite capricious.

This is due to the fact that not every novice master will be able to work with such rods. If you do not have experience in such activities, then it is better to avoid such electrodes.

Popular types of electrodes

If you cannot decide on a choice, then you should pay attention to the most popular brands, they look like this:

UONI-13/55.
MR-3S; MP-3.
ANO.

The former are popular among experienced craftsmen. These rods allow you to achieve a high-quality seam, which is true at low outside temperatures. At the same time, the density indicators remain optimal.

When deciding which electrodes are best for an inverter, it is worth paying special attention to MP-3C rods, which are used when it is necessary to make a weld with high quality requirements. These electrodes are used to connect elements with direct and alternating current of reverse polarity.

The most universal brand is MP-3; it can be used to connect metal workpieces with a contaminated surface, rusty and damp structures. The most purchased among Russians are ANO. They do not require pre-calcination, and you can light them without much effort. In the end, you are guaranteed to get an excellent result, even when welding is performed by an inexperienced welder.

Selecting electrodes for different materials

Before starting work, you need to remember that products made from different materials require certain electrodes. If you plan to work with high-alloy or stainless steel, then it is best to use TsL-11 rods, which are manufactured according to state standards 9466-75. But if you plan to weld workpieces made of carbon steel, then OZS-4 electrodes are best suited.

If you are still deciding which welding electrodes are best to choose for an inverter, then you should pay attention to ANO-6. They are intended for products made of low-carbon steels. In this case we are talking about rods with ilmenite coating.

Low-carbon steels can also be welded using ANO-4, which have a rutile coating. Different grades of cast iron can be connected using OZCh-2. When purchasing electrodes, you should ask whether they have epidemiological certificates that guarantee high-quality welding. The use of material manufactured according to state standards also speaks about the safety of work.

For reference

An inverter is modern equipment with which you can weld different surfaces using almost all existing types of electrodes. This is the popularity of the device. However, when choosing the best welding electrodes, you must remember that not all rods provide high-quality results and excellent presentation of the seam.

In addition, safety issues will be compromised when using rods that are not recommended for this type of welding. This suggests that when choosing rods it is necessary to follow the recommendations of specialists.

Selecting electrodes for the Resanta device

Regardless of what brand of machine will be used for welding, the electrodes are selected according to the scheme described above. If you are faced with the question of which electrodes are best to choose for the Resanta 190 inverter, then you should be guided by the current settings and the diameter of the rods. The last parameter is selected depending on the thickness of the workpiece. If it is 1.5 mm or less, then it is better to use argon arc or semi-automatic welding.

Which electrodes are best for the Resanta inverter is of interest to many. Answering this question, it can be argued that the diameter of the electrode is selected, as mentioned above, according to the thickness of the steel. If it is 2 mm, then the diameter of the rod can vary from 2 to 2.5 mm. With a steel thickness of 12 mm, it is best to choose an electrode with a diameter of 5 mm.

Additional recommendations

When choosing the best electrodes for welding, you may be faced with the need to purchase a rod for a 13 mm workpiece. In this case, the diameter of the electrode will be 5 mm. This parameter will also be relevant for workpieces of more impressive thickness.

But as for the current, it is set depending on the diameter of the electrode. Thus, based on 1 mm of diameter, it is necessary to set 30 A. For a 3 mm rod, the current can be 80-110 A.

The final value will depend on the spatial position, the number of passes and the thickness of the metal.

Finally

If you have already decided for yourself which electrodes are best for the Resanta 220PN inverter, taking into account the above recommendations, then you must remember that identical and precise settings do not exist today. The wizard sets the current parameters independently using the method of error and trial. At high currents, you must be prepared for the weld pool to become less controllable and more liquid.

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Source: https://FB.ru/article/339080/svarochnyie-elektrodyi-kakie-luchshe-dlya-invertora

Installing a submersible pump in a well with your own hands - Metals, equipment, instructions

Now the work on drilling a water well has been completed, the siege column has been installed, and the well has been washed and ready for operation.

For uninterrupted operation of the source, all that remains is to select pumping equipment for the well and install the pump according to all the rules.

We will discuss below how to do this correctly with your own hands and how to smoothly start a deep-seated unit. And for example, look at the video located in the material.

Points to consider

When choosing a borehole submersible pump, give preference to centrifugal models. They have a less destructive effect on the walls of the well shaft, unlike vibration pumps

Before installing the selected well pump into the casing and starting it smoothly, it is important to consider several points that will make the pump even more efficient:

So, whatever the immersion depth of your unit, you should choose a submersible pump model that is equipped with protection against dry running. Thanks to such a system, even a sharp and critical drop in the water level in the well will not in any way affect the performance of the equipment. Dry running protection will work instantly and protect the pump from combustion.
An important point is not only protection against dry running, but also the diameter of the unit itself. The recommended gap between the walls of the casing pipe and the walls of the pump body should be 4 mm. If there are more, then even better.
When choosing a borehole submersible pump, give preference to centrifugal models. They have a less destructive effect on the walls of the well shaft, unlike vibration pumps. In addition, the use of a vibration unit, even with protection against dry running and a check valve, is not recommended, especially for sand wells. There is a risk of loosening the sandy bottom.
And it wouldn’t hurt to take into account the pump’s performance for high-quality and uninterrupted water lifting. To do this, you need to calculate the average amount of water consumed per family per day.

Complete set of tools and working elements

Before lowering a pipe already connected to the pump into the well, it is advisable to level it by securely fixing it in the area

In order to correctly and reliably install a deep submersible pump in a water well, you need to stock up on the following items and components:

Pump of the selected model;
Water intake pipe in the form of a PVC hose of the required length and diameter;
Electrical cable;
Safety cable (preferably made of stainless steel) of the required length;
Check valve;
Plastic fitting for connecting the pump to the water intake pipe;
Adjustable wrenches;
Plumbing tape FUM or Tangit (winding).

Important: before lowering a pipe already connected to the pump into the well, it is advisable to level it by securely fixing it in the area. That is, stretch the desired section of pipe across the area and secure it with bricks or other heavy objects. But avoid damaging the PVC.

Installation steps for a submersible pump

First of all, you need to attach a check valve to the outlet pipe of the pump.

The installation diagram of the unit in a water well will be as follows:

First of all, you need to attach a check valve to the pump outlet. It is important to install it so that the arrow drawn on it faces up. We wrap all threaded connections with tape and securely clamp them with an adjustable wrench.
Now it's time to install the adapter-fitting for the pipe. It is this that will allow you to attach a submersible well pump to the water intake pipe.

Important: installation of the fitting must be done in two stages. First we attach its smaller (lower) part. To do this, we tightly wrap the plumbing tape and fix the thread of the fitting to the thread of the check valve. We clamp everything well with keys. In this case, an additional layer of sealant can be used at the junction of plastic and metal.

Insert the water inlet pipe into the existing hole with a rubber seal until it stops. In this case, first, not its base, we will put on the second part of the fitting with the thread towards the joint. After the pipe is inserted into the front part of the connecting element, we bring its second part along the pipe and securely join it using a thread.

Installation of safety hummock and cable

We connect the electrical cable and the water intake pipe together using the tying method

Now we proceed to fastening and installing the safety rope and electrical cable according to the further scheme.

And if everything is clear with the wire (it is connected to the pump), then the safety cable, selected in accordance with the parameters of the well, is attached to the base of the pump and secured with special steel clamps.

In this case, the clamps themselves and the end of the steel cable must be insulated with special adhesive tape (insulating tape).

We connect the electrical cable and the water intake pipe together with our own hands using the tying method. To do this, you can use plastic clamps or just electrical tape.

It is important to avoid putting too much tension on the cable or letting it sag. This method of installing the wire and pipe will prevent the formation of a loop around the pump during its operation.

And this, in turn, will protect against jamming of the pump in the well when it is lifted.

We fasten the safety cable to the pipe and cable in the same way with clamps. It can be fastened with a simple duct tape tie with a large pitch.

Lowering the pump into the well

In order to hermetically close the wellhead, you need to cut off the upper part of the casing, which has a thread. Since this particular section is wider in relation to the rest of the column

And the last stage of installing a well pump on water with your own hands according to the diagram is installing a pipe into the hole in the head. In order to hermetically close the wellhead, you need to cut off the upper part of the casing, which has a thread. Since this particular section is wider in relation to the rest of the column.
Having cut the thread, we disassemble the head into two parts and put the lower one on the pipe. At the top you need to lay a dense rubber layer.
We thread a water intake pipe into the hole in the upper part of the head, and pass the cable and cable through special bolts located on the inside of the cover.
We slowly and carefully lower the pump into the well and carry out its smooth start. Water should flow out of the pipe with sufficient pressure.
We install the upper part of the head and securely fix it with bolts.
After the well pump has been mounted and smoothly started, all that remains is to connect the water inlet pipe to the individual water supply system.
The minimum distance from the pump to the bottom of the well should be 1 meter. And the minimum immersion depth of the unit is 0.5 meters.

Source: https://spb-metalloobrabotka.com/elektrody-dlya-svarki-postoyannym-tokom-kakie-luchshe/

Which current is more dangerous for human life in case of damage - constant or alternating?

Constantly encountering electricity at home and at work, people sometimes forget that failure to comply with basic safety rules can lead to serious consequences, including death. Every person must be aware of the invisible dangers posed by electrical appliances in order to avoid serious electrical injuries.

Which current is more dangerous for human life

Alternating current is used much more often in industry and everyday life. People have long been accustomed to this and few people know that in the 19th century Nikola Tesla and Thomas Edison launched a real “current war”, the results of which determined the further path of industrial development.

Conductor of electricity

One of the arguments given by Edison in defense of direct current was its lower danger to humans compared to alternating current. Under the same conditions (up to 500 V), the force of alternating current on the body is 2-4 times higher.

In the end, the AC concept won. It is much lighter and transmits over long distances with less loss, is easily converted, and is more convenient for the operation of electric motors.

The effects of electric current on the human body:

Thermal (up to 60%) - heating of the skin and internal tissues up to burns;
Electrolytic - decomposition and disruption of the physical and chemical composition of organic liquids (blood, lymph);
Mechanical - stratification and rupture of internal organs under the influence of electrodynamic shock;
Biological - convulsive contractions of muscle and nervous tissue.

Attention! Loss of consciousness, as well as disruption of the heart and lungs, occurs when the frequency of the electrical flow and heart contractions coincide.

Variable

An electric current that changes in magnitude and direction over time. The flow of electrons constantly oscillates at a certain frequency.

Sinusoid of electron motion

Why is alternating current more dangerous for human life than direct current?

By its nature, it causes stimulation of the nervous system, contraction and relaxation of muscles, which increases the likelihood of atrial fibrillation, leading to cardiac arrest;
The frequency of the passing pulse reduces the resistance of the human body;
An electrical conductor carrying alternating current has a high attractive force.

On a note! The upper limit of alternating current strength that does not lead to damage or serious consequences is 1.2 mA.

Constant

Electric current is the movement of charged particles from minus to plus, the polarity and voltage of which are constant. The flow of electrons goes strictly in a straight line without fluctuations. The severity of the lesion is directly proportional to the amount of voltage applied.

DC generator

Reasons for the lower danger of direct current compared to alternating current:

Causes muscle spasm, but does not lead to cardiac dysfunction;
The resistance of the human body is higher when the electron oscillation frequency is zero;
A single blow allows you to quickly stop direct contact with an electrical conductor, throws a person back, reducing the duration of exposure to damaging factors on the body.

Attention! The upper limit of safe exposure to direct current is much higher - 7 mA.

Comparison of the effects of alternating and direct electric currents on the body to find out which current is more dangerous.

Electric current strength (mA)	Alternating current	D.C
0,6–1,5	Slight tingling	No sensations
2–3	Mild cramps	-«-
5–7	Severe cramps	Slight tingling, slight sensation of warmth
8–10	Severe pain, the upper threshold of the ability to open your hands independently	Symptoms of skin tingling and heating increase
20–25	Paralysis of limbs, inability to release the current source	Mild cramps, strong heating of the skin
50–80	Cardiac dysfunction, respiratory center paralysis	Difficulty breathing, severe convulsive spasms
90–100	Respiratory arrest, possible atrial fibrillation	Paralysis of the respiratory system, the likelihood of the victim being thrown back, causing physical injury
200–300	When exposed to more than 0.1 s, cardiac arrest, tissue destruction	Thermal destruction of tissues

Note! It is important to know what current is life-threatening - 50-100 mA, more than 100 mA - fatal.

Providing assistance in case of electrical injury

Why is this or that current dangerous?

The severity of damage to the human body depends on many factors:

Current and voltage;
Duration of exposure;
Type of current and frequency;
The resistance of the human body is a variable value, depending on many factors.

Various injuries due to electric shock are caused by the nature of the movement of particles: alternating causes chaotic convulsions of internal organs, constant – heating, burns, destruction of body tissues.

Current and voltage

An important parameter that determines the danger of injury is the current strength. An alternating current of 10–15 mA and above is considered dangerous, and a constant current of 50–80 mA.

For humans, alternating current is more dangerous than direct current at the voltages that people most often encounter in everyday life. A direct electric shock occurs at a voltage of 120 V; for alternating current, a similar shock occurs at U = 42 V.

At high voltages (500 V and above), direct current poses the same danger to the body as alternating current. At a higher U, it becomes even more dangerous to humans.

Ammeter measurement

Damage duration

With increasing exposure time, the epidermis is destroyed at the site of contact, the resistance of the human body decreases, and the strength of the flowing electric current increases. Increased sweating at this moment can reduce resistance tenfold. Prolonged contact with electricity causes the accumulation of negative effects on body tissues.

Human body resistance

The law of physics says: the higher the resistance, the lower the current in the circuit. The condition of the epidermis largely determines the amount of general resistance of the human body (up to 90%). Intact, dry, rough skin has dielectric properties. The resistivity of the human body in this case is 40,000–100,000 Ohms.

Reasons for reducing the resistance of the human body

The value is not constant. Depends on the area of influence and density of contact, the duration of current passage through the body. The thickness of the skin is important - in women and children it is thinner and is more susceptible to damage.

Reasons for decreased resistance:

High temperature, sweating;
Damage to the epidermis;
Increased humidity in the room.

Important! Persons who are intoxicated are at particular risk of electrocution due to a sharp drop in resistance.

Current type and frequency

The number of pole oscillations in a power supply network is called frequency. In Russia and the CIS countries, the standard value is 50 Hz, which means that every second the direction of the alternating current changes 50 times. This unit of measurement has nothing to do with direct electric current; electrons move in one direction.

Reference! The greatest danger is caused by lesions with frequencies in the range from 50 to 500 Hz.

Frequency 50 Hz

At a frequency above 20 kHz, thanks to the skin effect, alternating current does not cause harm to a person, passing over the surface of the skin and without penetrating into the body. Nikola Tesla proved this experimentally by touching electrodes with his bare hands with a potential of 100 kV with a frequency of 100 kHz.

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Under what circumstances can a person be shocked by electric shock?

During operation and repair of electrical equipment, there is a possibility of contact with exposed live wires. You can get an electric shock by touching two wires with different phases. By contacting one phase, a person becomes a conductor, touching grounded metal structures or standing on a wet floor.

In everyday life, the source of damage is often faulty electrical wiring, broken sockets and switches. Electrical injury can result from faulty insulation of electrical appliances connected without grounding.

Violation of the operation of household electrical appliances

An electric shock can occur without direct contact with a conductor. In conditions of high humidity and close to a source of electricity, insulation breakdown may occur and an electric arc may occur.

Broken power lines cause wires to come into contact with the ground. They are capable of creating a step voltage within a radius of up to 10 m. A potential difference arises between two points on the surface located at a distance of one human step.

The severity of the injury depends on the path the current travels through the human body. Electric current always travels the shortest distance towards the ground.

Important! The most dangerous are lesions of the heart, brain, spinal cord, and lungs.

Paths of electric current through the human body

Possible paths:

“Hand-to-hand” is the most common practice (40%). A person touches the phase with one hand, and the grounded surface or zero phase with the other. The risk of heart damage is less than 5%.
“Hand-legs” - when one hand touches the conductor, the electric current path is closed through both legs to the ground. Passage through the heart is 3-7%. The option of touching the right hand is more dangerous (20%).
“Leg-to-leg” - the lesion occurs under the influence of step voltage. Electrical injury is rare (6%).
“Head-foot” (5%)—creates the most dangerous loop and requires urgent resuscitation measures.

When performing electrical work, it is recommended to use protective equipment: dielectric gloves, galoshes, rubber mats. Power tools must have insulated handles.

Electric current is dangerous to the human body. To prevent injury, you must follow simple safety rules. Reliable means of protection against damage in everyday life - installation of RCDs and differential circuit breakers.

Source: https://rusenergetics.ru/polezno-znat/kakoy-tok-opasnee-postoyanniy-ili-peremenniy

What current for which electrode: choice, constant and alternating, welding electrodes - differences between alternating and constant

When carrying out the welding process, it is necessary to select the correct current value. It is this parameter that largely influences the quality of the weld.

A low welding current can lead to instability of the arc, the appearance of unwelded areas, the welding process will be constantly interrupted and, as a result, the welder will receive a poor-quality connection.

A value that is too high will result in overheating or burnout in the welding zone, as well as intense spattering.

In general, the choice of voltage indicators is influenced by several factors :

brand and diameter of welding materials;
spatial position of the rod during welding;
voltage polarity (see the peculiarities of constant and alternating welding);
seam size ;
method ;
type and thickness of metals being welded.

What current for which electrode

The correct choice of current for welding with electrodes is the key to a comfortable working process, a high-quality weld and the entire product as a whole. For each brand there is a recommended voltage value. This information is written on the packaging of welding materials. You can find approximate figures below.

Welding current for 4 mm electrode

Rods with a diameter of 4 mm are common. Their demand is due to the fact that such consumables are suitable for working with large and small seams. The voltage force when welding with this rod ranges from 110 to 200 A.

Welding current for 3 mm electrode

Welding voltage for consumables with a diameter of 3 mm. should be in the range from 65 to 130 A. Before carrying out work, it is recommended to set the average value to 80-90 A. During the welding process, this will help determine what current is required for welding with a 3mm electrode. is optimal.

Welding current for electrode 2 mm

At 2 mm. a voltage of 30 to 80 A . The wide spread in values depends on the metal and the chosen spatial position.

Important! Please remember that these values are relative. In practice, the current strength depends on the brand. Each brand has its own indicators written on the packaging

Source: https://WeldElec.com/svarochnyi-tok/

How to choose the current for welding with an inverter

For a novice welder, choosing an electrode can be a problem: there are more than two hundred brands with different properties, purposes and characteristics. Moreover, about 100 brands are suitable for manual arc welding with inverter machines.

It’s impossible to talk about everyone, and to begin with, it’s not necessary. Let’s just briefly describe the main types and which electrodes for inverter welding are most suitable for beginners.

We will also talk about what diameter to take and what current to set for welding metal of different thicknesses.

What is an electrode and what is the coating for?

An electrode is a piece of metal wire with a special coating - coating. During welding, the core melts due to the temperature of the arc. At the same time, the coating burns and melts, creating a protective gas cloud around the welding area - the weld pool.

It blocks access to oxygen contained in the air. As the coating burns, part of it turns into a liquid state and covers the molten metal with a thin layer, also protecting it from interaction with oxygen.

So the coating ensures good quality of the seam.

The welding electrode consists of a core and a protective coating

Before starting welding, any electrode is inspected: the coating should not be chipped. Otherwise, you will not achieve uniform heating and a high-quality seam. Also pay attention to the tip of the electrode: the thickness of the coating should be the same on all sides. Then the arc will come out in the center. Otherwise it will be displaced. For experienced welders this is not a big deal, but for beginners it can create significant problems.

It is necessary to monitor the moisture content of the coating. Some of them ignite very poorly in high humidity (for example, SSSI). Due to such “capriciousness” of the coating, they need to be stored in a dry place, ensuring as airtight packaging as possible. You can put the box in a bag, and also put in a few bags of salt that come in shoe boxes.

You should not buy wet electrodes: they can, of course, be dried, but their characteristics will decrease. If it does happen that the electrodes become damp, you can dry them in a regular household oven at low temperatures (they are usually indicated on the packaging). The second way is to put it in a dry, well-ventilated area for a long time.

Coating (protective coating) of electrodes can be: basic, rutile, cellulose and acidic.

Types of coating and their characteristics

There are only four types of coatings:

Basic (USSI) and cellulose coatings are only suitable for DC welding. They can be used on critical seams: they create a strong, elastic seam that is resistant to impact loads.

There are more than 200 brands of electrodes for welding, about 100 of them can be used in manual arc welding

The other two (rutile and acidic) can work with both alternating and direct current when welding. But acidic coating is very toxic: you can work indoors only if the workplace is equipped with forced exhaust.

Rutile coating has a greenish or blue tint, the electrodes are easy to ignite. They ignite well even if the inverter has a low open circuit voltage (for reliable ignition of the main coating, a good current-voltage characteristic is required; how to choose an inverter welding machine, read here.). When welding with rutile electrodes (MP-3), the metal hardly splashes, but there is a lot of slag and it is not easy to remove: you have to work with a hammer.

How to choose electrodes for inverter welding

First of all, the composition of the core is selected: it must be similar to the type of metal being welded. Structural steel is the most commonly used material in households. The electrodes should be made from the same wire. Sometimes you still have to cook stainless steel. Then the core should also be made of stainless steel, and for highly alloyed and heat-resistant ones it is made of metal with the same characteristics.

You can perform all the work around the house or at a construction site using just a few brands of electrodes:

They are recognized by many as the best electrodes for beginners who work with inverter welding machines: they are easier to work with, at the same time, they allow you to weld high-quality seams even without significant experience. Below are the characteristics and general application of those consumables that many experts consider good electrodes for an inverter. In any case, they are often recommended for beginning welders to gain experience.

Electrodes with rutile coating MP 3

These are perhaps the most popular welding electrodes for inverters among beginners: UONI 13/55 (To enlarge the picture size, right-click on it)

Most often, beginners are advised to start mastering welds with MP-3 electrodes. They light up easily, even with a not very good current-voltage characteristic of the welding machine, provide good protection for the weld pool, and make it quite easy to control its position. If the electrode does not ignite, calcine it at a temperature of 150-180° for 40 minutes.

They are used in devices with alternating current (welding transformers) and direct current (welding rectifiers and inverters). Inverters are usually connected with reverse polarity (+ on the electrode). Suitable for any type of seam, except vertical from top to bottom.

MP 3 electrodes are not picky about the quality of the surfaces being welded. They can be used even on untreated, rusty and wet parts. Welding is carried out with a medium (2-3 mm) or short arc.

The MP 3 feature is very important for novice welders: they “hold” the arc well and are easy to work with. This is why not all professionals love this brand: they call them sparklers. They cook too softly: slow movements are necessary for good heating. What the pros don't like, is just what beginners need. Try to start learning welding with MP3. Everything should work out for you.

Diameter of electrode LEZ MR-3, mmLength, mmRecommended welding current, АWeight of pack, kgPrice, rub

2,0	250	40-60 A	1,0	146
2,5	300	60-100 A	1,0	120
3	350	70-100 A	1,0	95
4	450	80-170 A	1,0	91
5	450	130-210 A	1,0	91

Source: https://crast.ru/instrumenty/kak-podobrat-tok-dlja-svarki-invertorom

6 best welding electrodes

Nowadays you can easily find a wide variety of welding electrodes in specialized stores. They differ from each other not only in characteristics, but also in reliability. Unfortunately, very often people purchase products that can last an extremely short period of time.

Our site strives to prevent this from happening. Stop wasting your money! Buy a quality product that will serve faithfully for a long time. Perhaps you will overpay slightly. But eventually you will realize that you actually saved money.

In a word, choose those welding electrodes that are mentioned in our article today.

Which brand of welding electrode should I choose?

Now welding electrodes have learned to be produced in a variety of countries. They are created in China, Russia, the USA and many other countries. Unfortunately, practice shows that domestic electrodes are inferior to foreign products in terms of quality and other parameters. And yet progress is noticeable.

If this continues, in a few years the level of performance will become much higher. In the meantime, along with electrodes from Russian companies, we will also recommend products distributed under foreign brands - they often show themselves in work from a more positive side.

The most popular welding electrodes in Russia are under the following brands:

1. ESAB-SVEL

2. Kobelco

3. Resanta

4. SSSI

5. Lincoln Electric

Some of these companies specialize in producing both rutile and basic coated electrodes. Others create electrodes of strictly one type.

SSSI 13/55

This electrode should be used for DC welding. It is ideal for use in critical areas. It is noted that the weld pool will be reliably protected from the effects of oxygen, for which we should thank the carbon dioxide released when the coating burns. One kilogram of this substance will cost a penny. But you need to take into account that most often UONI 13/55 electrodes are sold in packages of 3 kg.

The presence of coating here simultaneously plays a negative role. The fact is that the product is very difficult to light. Some novice welders spend a lot of time on this process. Also, re-ignition is difficult here. The melted coating hardens and insulates the metal, which requires stripping the end of the electrode. But it should be noted that it is with the help of an electrode with a basic coating that the most durable and aesthetic seams are obtained.

Advantages:

The appearance of slag pits in the cooled seam is completely excluded;
The seam is aesthetic and very durable;
Minimum cost of the product;
Widely distributed in specialized stores.

Flaws:

Difficult to light;
Re-ignition is possible only after stripping the end of the electrode;
It takes time to get used to the features of this type of electrode.

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Kobelco LB-52U

This is already a very expensive substance produced in Japan. Rolling off the production line of Kobe Steel, Ltd. the electrode is sold in our country at an inflated price per 1 kg. In this case, one package usually consists of four to five kilograms of the substance.

But this product does an excellent job of welding low-carbon steels, where there is no possibility of double-sided welding. In particular, pipelines are welded with these electrodes. There are no complaints about the strength of the resulting seam.

In many cases, the strength reaches 588 N/mm2, which is an incredibly high figure.

Of course, the base coating makes using the electrode slightly more difficult. Before work, it is necessary to calcinate at a temperature of about 300°C. This will remove moisture, as a result of which combustion will significantly improve, and at the same time the quality of the seam will improve. The creators also recommend cooking at constant current. However, a variable can also be used, but then the result will be slightly worse.

Advantages:

The seam is strong and clean;
Ideal for welding low-carbon steels;
Easy creation of seams in any direction.

Flaws:

Not everyone will like the price;
Calcination is necessary, since the product is sensitive to dampness.

OZL-8

These domestically produced electrodes are primarily intended for welding steel with a high nickel and chromium content. That is, these are the electrodes that should be used to weld stainless steel. This product has one limitation. It is only suitable for welding machines using reverse polarity direct current. The arc should be short.

If the above conditions are met, the welder will receive a strong weld that is not prone to hardening and corrosion. In a word, OZL-8 electrodes show themselves ideally when working with highly loaded components, including those used under conditions of alternating loads.

Unfortunately, after welding, some slag is released into the light. But it separates easily, you won’t spend a lot of time on it. When cooling, the seam does not crack, but it should not be cooled sharply so that crystallization does not occur, which reduces strength. Like other electrodes with a basic coating, these products require calcination at high temperatures. This makes ignition somewhat difficult, or rather delays.

Advantages:

Easy seam management;
Ideally welds highly loaded components;
Does not crack when torn off;
Best suited for working with stainless steel.

Flaws:

High price;
When humidified, the characteristics seriously deteriorate;
Usage restrictions typical for such electrodes.

Lincoln Electric Omnia 46

The most respected company in the welding market is Lincoln Electric. This American company has existed for over a hundred years. The first coated electrode was produced by her back in 1927. Since then, the engineers of this company have accumulated a wealth of experience. Therefore, you should not be surprised that Omnia 46 electrodes, which have a rutile-cellulose coating, immediately after their release earned the respect of many welders and specialized publications.

Despite their foreign origin, these electrodes are quite inexpensive. You can find different packs in stores; they usually contain from four to six kilograms of electrodes. In any case, you will spend less than a thousand rubles! Beginners love this product the most. The fact is that Omnia 46 electrodes easily flare up even on cheap welding machines.

They are not very sensitive to the length of the arc, which is also good news. Experts note a small number of sparks that occur during operation. This is important, as this improves fire safety. The slag can be easily separated after work, allowing welding of contaminated or rusty steel. Buyers have no complaints about the strength of the seam.

Often, even pipelines are welded with such electrodes, although they were not originally intended for this.

Advantages:

The seam is very durable and resistant to stress;
Does not require a short arc;
Very easy ignition on any inverter;
Even a beginner can handle the arc;
Reasonable cost.

Flaws:

Electrodes can quickly become damp (then they will require calcination).

ESAB-SVEL OK 46.00

These electrodes are both Russian and foreign. This is explained by the fact that they are produced here, but strictly under the control of the Swedish company ESAB. The product is sold at a relatively low price. This product has no equal in this price category. Even with partial dampness, the electrodes burn stably.

Ignition takes a matter of seconds on any welding inverter. You can work with electrodes with both direct and alternating current. Experts note that the product works in any direction of the seam, and the minimum current threshold for these electrodes is lower than that of competitors. All this allows the Swedish-Russian product to be used for welding thin-walled parts.

The main advantage of rutile-coated electrodes is that the surface of the steel being processed does not need to be cleaned. The product is not afraid of either pollution or corrosion. All slag can be easily removed after work. The cooled seam is strong and viscous. To calcinate a very cool electrode, it is enough to heat the welding machine to only 80-90 degrees.

Advantages:

Can work with contaminated and rusty steel;
The price tag can hardly be called high;
Possible operation at minimum current;
Very easy ignition.

Flaws:

Not suitable for pipelines, since the strength of the seam is still not maximum.

Resanta MP-3

It is possible that Resanta MP-3 electrodes are the most common in our country. The Resanta brand unexpectedly became very popular, not least due to the fact that most often there are no special complaints about products under this brand.

The above electrodes have an average price tag. The product turned out to be successful, its main disadvantage is that it works noticeably worse when damp. If you need a strong seam, then the damp product will require calcination. At a temperature of 150-170 degrees, this process will last about an hour.

Like other rutile electrodes, Resanta MP-3 can be ignited with almost an ordinary match. This product also allows you to conduct an arc in any direction. It is not afraid of rust or contamination - the slag is then easily removed. The product has no particular defects.

While many competitors, when working with steel with a high carbon content, suffer from recrystallization, this product is completely insensitive to the quality of the steel being welded. And yet, there is no need to buy Resanta MP-3 for welding high-carbon steel - there are electrodes with a basic coating for these purposes.

Advantages:

Optimal price tag;
No tendency to form pores;
The slag is easily separated;
Minimum arc length requirements;
Easy to light;
Can be used with alternating and direct current.

Flaws:

When dampened, the quality of the seam noticeably drops.

Which welding electrode to buy

1. If you have already worked with electrodes that have a basic coating, then you can purchase UONI 13/55. This product is inexpensive and provides a very durable seam. Also among its advantages is the fact that these electrodes can be found in many stores.

2. Kobelco LB-52U also has a base coat. In this regard, ignition here is possible only after calcination, which removes all moisture. This electrode must be purchased if a pipeline or some other serious object is being welded that does not allow double-sided welding.

3. If you are welding stainless steel, then you need to buy OZL-8. This is an expensive substance, but it is ideal for welding steel containing nickel and chromium. The product's disadvantages are typical for an electrode with a basic coating.

4. If you need fast-igniting electrodes, then you should consider purchasing the Lincoln Electric Omnia 46. Also, this product will not greatly affect your budget. The electrodes create a strong seam, otherwise they would not be included in our rating.

5. Another good example with rutile coating is ESAB-SVEL OK 46.00. This electrode also does not require serious calcination, and it is less afraid of dampness than others. To work with such an electrode, a minimum current is required, which allows you to weld thin-walled steel.

6. Resant MP-3 electrodes perform slightly worse. If they become damp, they will require long-term calcination at medium temperature. Otherwise, the seam will not be of the highest quality.

Do you want to receive up-to-date ratings and selection tips? to our Telegram.

Source: https://vyboroved.ru/remont-i-nedvizhimost/972-luchshie-svarochnye-elektrody.html

Voltage stabilizer for welding inverter

Many welders experience network sagging. When you urgently need to finish a job, you have to change the diameter of the electrodes, switch from 4 to 3. It is clear that it will no longer be possible to thoroughly weld a deep seam.

With a voltage stabilizer for a welding machine, fluctuations in the parameters of the power supply network are not terrible. The device supplies current with the required voltage. The welding becomes uniform. Choosing a stabilizer is not easy. Manufacturers offer a large selection. Experts will tell you what criteria to pay attention to.

Design and principle of operation

Often a decrease in voltage is recorded in the private sector and densely populated urban areas. The surges are associated with the simultaneous connection of household heating appliances. The stabilizer is designed to protect against significant fluctuations in the network and maintains the power required for the welding arc.

It is no coincidence that the second name for a voltage stabilizer for welding is an electric arc stabilizer. The stabilizing effect is based on the effect of magnetic induction.

The equipment is similar to a transformer: the electric field of the first coil generates an inductive or induced current in the second winding, connected in a single circuit with the welding machine.

When the voltage drops to a critical level (180 V) in the first winding, a reactive coil is connected in the secondary circuit. It supplies a compensating charge. The number of connected turns is proportional to the voltage drop.

When the network is 240 V (such fluctuations also happen), the regulator automatically reduces the number of turns of the secondary winding. There is again a stable signal at the output of the supply circuit.

Stabilizing equipment turns on only when the input signal decreases or increases. Connecting additional turns will prevent the electric arc from dying out during the welding process. Voltage stabilization occurs automatically without the participation of a welder.

The principle of electronic stabilizing devices is more complex; semiconductors and capacitors are involved. Due to the converter circuits, energy losses are compensated; the input current indicators do not affect the output voltage or amperage. Similar stabilizers are built into powerful inverters. Professional welding equipment does not require external protection.

Short.

The voltage stabilizer maintains the required voltage during power surges, which allows you to use the welding machine to its fullest potential. In dacha cooperatives, voltage drop in the network is a common problem. This is where a voltage stabilizer comes to the rescue.

Technical parameters of stabilizers

The characteristics of the stabilizing devices must correspond to the welding equipment. A classification of stabilizers for welding according to their intended purpose has been developed. Equipment produced:

maintaining a transformer welding machine in working condition;
configured for semi-automatic;
working with devices with inverter type converters.

Source: https://svarkaprosto.ru/oborudovanie/stabilizator-napryazheniya-dlya-svarochnogo-invertora

Welding current and electrode diameter. Dependency and selection

I recently received several questions from readers, and they were all about welding current and electrode diameter . I decided that my answers would be useful for many amateur welders to know and I am writing them for everyone. I will paraphrase the questions in my own words.

Welding current and electrode diameter do not match each other

PROBLEM. My reader uses a 3 mm electrode and sets the current to 50-60 amperes. At the same time, he experiments with different distances from the electrode to the metal, but he cannot produce high-quality seams. If you bring the electrode closer to the metal, the electrode sticks, but if you move it further, you get separate drops of metal and “snot.” And when you try to weld thin metal, and even with a high current, the metal is burned through.

SOLUTION. In this situation, the error lies in the discrepancy between the set welding current and the electrode diameter used. Because at a current of 50-60 amperes you need to use an electrode with a diameter of 2 mm or even less. And when using a 3 mm electrode, the current should be set to about 100 amperes.

For welding thin metal, you should also use a 2 mm electrode, and preferably 1.6 mm. (Although, of course, it would be better to know what kind of metal my reader calls thin.) Also, for welding thin metal, amateur welders will find the pulse mode of the inverter useful, and if there is no such mode, then they can use the technique of making welds with an arc break.

When the current decreases, the diameter of the electrode should also be decreased.

PROBLEM. Another reader of mine bought an inverter with a maximum power consumption of 3 kW and a 2.8 kW gasoline generator, and the welding inverter does not have enough power for normal operation. The question is whether anything can be done other than buying a more powerful generator or a different welding machine.

SOLUTION. If the generator power is not enough to operate the welding machine, then you need to reduce the welding current used to make the seams. But then, along with a decrease in current, it will be necessary to use an electrode of a smaller diameter - otherwise it will stick and there will be a lack of weld penetration.

But when reducing the diameter of the electrode, depending on the thickness of the metal being welded, it may be necessary to cut the edges for better penetration of the welded joint.

Unfortunately, in his question the reader did not indicate the welding modes and the thickness of the metal being welded, therefore, without these numbers it is impossible to give more specific advice.

Source: http://www.elektrosvarka-blog.ru/svarochnyj-tok-diametr-elektroda/