Major faults in welding inverters

Repair malfunctions of welding inverters begins primarily with diagnostics. This equipment allows to perform welding work in more comfortable conditions. And any breakage knocks out of the rut, but due to the complexity of the design of the welding inverter, not every breakage is amenable to self-repair.

Welding inverter device

The device welding inverter.

Features of repair intervention

Comparing a common welding machine with a welding inverter, it is immediately necessary to say that the first option is an electrical product, while the second is electronic. Therefore, diode bridges, transistor connections, zener diodes and other components of electronic basic circuits should be checked.

Functional diagram of the welding inverter

Functional diagram of the welding inverter.

To remove equipment malfunction, you should have basic skills with tools such as an oscilloscope, voltmeter, multimeter and others.

The main problem of such equipment is not even the failure itself, but the correct diagnosis. And here certain difficulties arise, since it is necessary to have a basic knowledge of electronics and to understand the very design of the device. In the opposite case, it is better to entrust the work to specialists, otherwise all efforts will be wasted.

Back to table of contents

The principle of operation of inverter welding machines

The equipment operates due to the gradual conversion of the incoming signal of the current, namely:

Welding inverter transistor

Transistors are the weakest point of inverters, so the repair of welding machines begins with their inspection.

  1. Due to the presence of the converter rectifying incoming electrical currents.
  2. Rectified currents are converted to high frequency alternating signals.
  3. Due to the power transformer, the voltage drops to the welding level.
  4. High-frequency current goes into a constant stage with the help of an output rectifier.

In order for all these processes in the welding machine to be performed at the proper level, the electronic filling of the equipment must be in good condition. The main node in the design of the welding inverter is the input current rectifier, then the control board is important because it is the center of transistors and the output rectifier.

Immediately, it is worth noting that every manufacturer can equip their products with a different layout of modules, but the main equipment remains the same.

Why is it important to know the principle of operation of welding machines? Knowledge of the location of all components will help to make the correct diagnosis of equipment and quickly troubleshoot.

Back to table of contents

Why breaks the technique?

First of all, malfunctions occur because the welding inverter is used incorrectly. The second reason is noncompliance with operating conditions.

There are several main reasons why the technique stops working:

Cable check for damage

If there is no welding with the machine turned on, check the cable connection of the electrode holder.

  1. Operation of the apparatus occurs in conditions of high humidity, for example, in the rain or snow. Water and inverter are incompatible things.
  2. Poor ventilation technology contributes to the accumulation of dust inside the case. Thus, the electronic circuits do not receive adequate cooling, so if you plan to use the welding machine in places where there is a lot of dust (for example, construction sites), you must constantly clean it from accumulations.
  3. Each model of the device has its own operating mode, in case of non-observance of which overheating occurs, and this already provokes faults in the equipment.

Alas, to be honest, such failures of welding machines can be corrected only in case of highly skilled intervention.

If a newbie takes on the technique, then the appeared malfunction can be considered serious, but in fact everything is much simpler: the wrong choice of welding mode. Therefore, before starting work, it is better to get acquainted with the process itself in more detail, and only then take up the tool.

“Simple” breakdowns can be:

The instability of the welding arc during welding

If during welding, excessive spattering of the metal of the electrode and arc instability occurs, then the cause may be an incorrectly chosen welding current value.

  1. The welding arc does not have constancy, or there is a strong splashing of the molten metal. This can occur in cases where the device is given an incorrect current value. In order to properly adjust this setting, take into account the diameters of the working electrodes and the speed of the work itself. Reducing the speed, the welding current itself should be directly proportional.
  2. Electrode sticking. This fault has several causes. Firstly, this may occur due to a decrease in the voltage in the power grid, which manufacturers of welding inverters do not allow. Secondly, sticking causes poor preparation of the working element to be welded, because the presence of an oxide film significantly affects (in a negative direction) the quality of the weld being created. Thirdly, such a malfunction can provoke an insufficient diameter of the power cable.
  3. The device is connected to the network, but at the same time, being in the on state, it does not perform welding. In this case, the cable is checked for damage, as well as how well the mass and the parts to be welded are connected.
  4. I can not turn on the welding inverter in the grid.

One of the common causes is the violation of the integrity of the cord. It may also be caused by the weak power of the circuit breakers that are installed on the switchboard. Their main purpose is to control the load exerted on the circuit breaker if the inrush current is too high.

These are the main points that a beginner may encounter when using a welding inverter. The smell of burning first of all indicates a serious breakdown if smoke starts to go out of the body. In this case, independent intervention is unacceptable, and you should immediately contact the service center to specialists. Otherwise, you can lose the welding machine forever.

Back to table of contents

The control board of the welding inverter is broken.

Current conversion circuit in welding inverter

Current conversion circuit in the welding inverter.

The process of repair work on the board includes checking diode bridges. To do this, the wires are desparded from the parts, after which it is possible to remove bridges from the board.

To check is carried out "ringing" of all segments. If a “short stack” is found, they start searching for a punched diode, and as soon as it is detected, it is replaced with a new element.

It may happen that the device will not work anyway, then you should pay attention to the board itself. To do this, it is tested, because the reliability of the control of the main keys of the device depends on this part.

Repair of welding inverters also includes a working test of the signals on which the operation of the tool depends. When the machine is in good working order, they freely enter the gate tires of the main node. For this purpose, use a device such as an oscilloscope.

From time to time the body of the welding inverter heats up to high temperatures. Why is this happening? There may be two options: firstly, the device is used by a beginner who is not well acquainted with the instruction manual, and secondly, during operation the wrong value of the current during welding is selected. Heating of the welding machine body occurs even when using the wrong electrode or giving excessive pressure to the machine.

To avoid such moments, you should carefully examine the data sheet of the product, which details the rules for working in optimal modes.

As for self-repair of welding inverters, for such works, besides knowledge, it is necessary to have appropriate diagnostic equipment.

Back to table of contents

Prevention of welding inverters

Welding inverter functionality

The functionality of the welding inverter.

Tool wear is due to heavy use of equipment, constant change of operators, non-compliance with recommendations for operation. Accordingly, the machine is threatened with breakdowns. To reduce such unpleasant situations, there are a number of recommendations that are prophylactic and help to use the device longer.

The following tips will help extend the work:

  1. The working platform must comply with the conditions of "comfortable" operation of the device.

That is, it is desirable that this was a closed room, with relative humidity and temperature. It is also important that these indicators have constant values. In addition, as noted above, the less dust in the working space, the longer and better the tool will work.

  1. The device is extremely contraindicated for contact with water and dust, and this is not to mention the simultaneous release of such substances on the equipment.

Before starting work, make sure that the voltage in the power grid is stable. In case of instability, it is not recommended to heavily load the arc, it is best if the indicator varies in the range of 10-15% of the nominal value. The same applies to work at large distances between the apparatus and the welding point.

The welding inverter should be handled very carefully, since the internal electronics is very sensitive to mechanical effects: shock, vibration and the influence of aggressive media.

Starting to work with the new equipment, it is best to give him a minimum load of time. Any experienced welder knows this. The tool at the beginning of operation must “accelerate”, otherwise it will quickly overheat, respectively, and will quickly fail.

For our climatic zone, sharp temperature fluctuations are very characteristic, so the device needs time to equalize its temperature with the environment. To do this, the tool must be held in the air, where welding is planned. The same applies to changing the place of operation, for example, if welding is first performed on the street, and then the operator moved into the room.

With professional use of the welding machine, the body should be removed once every 7 days and the insides should be cleaned. Although the same rule can be attributed to domestic exploitation. The same procedure is carried out in cases where the device has not been used for a long time.

Such careful handling will help keep the welding inverter intact for a very long time. Of course, minor problems of the welding machine can be solved independently, but neglecting operation will entail an appeal to specialists.

Add a comment