Welding transformers are a go-to accessory for regular as well as resistance welders. These units help in converting AC voltage from the power source into optimum voltage required for welding. Thus, leading to the formation of a welding arc. Taps are specialized items located on top of secondary coils present in the above-mentioned transformers and aid in the regulation of voltage arc.
These taps are connected in parallel and series circuits in multiple configurations to ensure outstanding performance and reduction in arc impairment. This article explains what are taps on a welding transformer, their configuration, location, and impact on the transformer design.
What Are the Taps on a Welding Transformer?
Before we get into the details of tapes on a welding transformer, it is essential to identify what actually is the welding transformer? Similar to common transformers that are used to regulate the AC current and voltage supplied to the final consumer, welding transformers are responsible for regulating the current for welding.
The device works by converting the AC current into a low voltage current and a high amperage, both of which are essential for welding. In addition to this, macro adjustments can also be carried out on the equipment with the help of specialized components known as primary and secondary taps.
Design of a Welding Transformer
It is a transformer in which a magnetic core is preset in combination with a thin winding coil. Apart from this, a secondary winding coil is also present in the system and acts as a platform for the inclusion of more than seven taps. Primary wires consist of more turns than secondary wires but possess a larger cross-sectional area. Other important tools for a successful welding operation alongside a welding transformer include a core, an ac supplier, an electrode, and rods.
Another type of transformer known as DC welding transformer is also available in the market and is similar to its previously mentioned counterparts in terms of performance. The only difference lies in the connection of the DC transformer with a rectifier, which helps in the conversion of DC voltage to AC voltage. In addition to this, manufacturers also recommend adding a conductor in the device to smoothen the current and the output.
As mentioned earlier, the welding transformer is responsible for converting the AC voltage into a voltage that is suitable for welding. This is carried out to form a welding arc; however, it might not be extremely easy to form a welding arc. It is a time taking process and requires a lot of effort to adjust the voltage to the desired value. The time taken in this process is known as recovery time.
Higher recovery time might lead to a reduction in ion generation, which later on impacts the overall performance and end result. Thus, experts advise that in order to maintain the balance of arc, the recovery time should be kept as low as possible. There are various methods to decrease the recovery time, most effective among which include increasing the voltage of the power source. This can be carried out with the help of taps.
Role of Taps in Achieving Desired Arc
There are two types of taps located on a welding transformer. These taps are characterized by adjustment in the voltage, which helps in decreasing the recovery time. All of this, on the whole, leads to the production of additional ions to maintain the welding arc. Low voltage has a negative impact on the performance of the cathode and can also lead to the loss of heat in extreme conditions. The taps are responsible for increasing the voltage during such instances and aid in regulating the cathode temperature.
The voltage can be increased by amplifying the current at the power source. The ideal voltage for maintaining a steady arc is 60 volts which can be achieved at the current supply of up to 250 amperes. A reduction in power supply up to 70 amperes leads to a dangerous increase in the voltage (80 volts), which might cause arc impairment. Therefore, in order to avoid such accidents, taps are installed inside a transformer to regulate the voltage and maintain it within permissible limits.
Location and Construction of Taps
There are various locations and configurations according to which taps are placed on top of the secondary coil. Mostly, they are present on the last layer of the coil with some gap between tap numbers four and five. In modern tools, coils are also integrated with a jumper that works with the tap to keep the voltage in control.
There are mostly seven taps included on a secondary coil. The taps with no breaks or gaps between them are usually connected with a loop present towards the end of the coil. As the last layer of the coil is placed far away from the finish line, so is the first tap. This makes the seventh tap relatively closer to the finish line.
This arrangement with the absence of breaks between the taps is known as the line tap arrangement. The previously mentioned jumpers are connected to the taps at both terminals. If the jumpers are located at one terminal, the configuration of taps changes, and its location corresponds to the desired voltage on the phase terminal.
In the case of winding transformers, the taps are present on the winding coils. These winding coils are connected with electrodes and welded pieces on both ends, respectively. Similarly, the taps are connected to a switch that is capable of generating a high current. This equips them to decrease the voltage when required.
These units are capable of regulating the voltage between 15 to 45 volts and prevent overheating as well as loss of heat due to unregulated decrease in voltage and cathode temperature. The taps that are connected to the secondary winding coils are capable of producing full output at terminals. When compared to common transformers, impedance value tends to be greater in welding transformers to the presence of taps.
High impedance contributes to the generation of welding arcs. Furthermore, due to high resistance between electrodes and welding pieces, increased heat production is witnessed in large welding transformers. These are the units that have multiple phase inputs and are more prone to arc impairment. So, the role of taps becomes even more prominent in such tools as compared to those with single-phase input.
Impact of Tap Configuration on Transformer Design
Different tap configurations are associated with different amounts of current and voltage production. Thus, you must carefully analyze the arrangement of taps inside a transformer for a better result. Another thing to note in this regard is that the arrangement of taps also affects the overall design and construction of the transformer.
Transformers with low current and voltage generations contain lower taps that are connected to the maximum turn cycle. In contrast, the design might vary in those that produce higher voltage for resistance welding. Similarly, the terminal taps also have different configurations for different devices. A loop-style terminal lacks insulation as compared to the brazed terminal taps.
Common Mistakes Made While Using the Taps
Mistakes often occur due to negligence or the lack of information about a certain object. Taps are a significant part of transformers and must be carefully handled to prevent unwanted mishaps. In the case of taps, the following is the most common mistake made by the consumers.
Mistake One: Use of Wrong Tape Size for Different Applications
There are various sizes of taps available in the market. Each of which is suitable for a different task. For example, the T15 * 60 tap is perfect for welding a rod with a diameter of 20 mm. However, people often make mistakes in this regard and use M12* 50, which might not work that well for a rod of a specified diameter. This is known as tap undersizing and can significantly impact your performance. Hence, you should carefully search about which size of tape is compatible with the object you are going to weld.
Mistake Two: Negligence in Safety
Another common mistake committed by most users is negligence in the safety procedure while installing and working with welded transformers. Lack of preventive measures poses a potential risk of electric shock, injury, and burns. This can occur in the case of open or naked wires.
The live wire contains 240 volts of power which can lead to serious consequences when touched with bare hands or feet. In extreme cases, getting electrocuted might even lead to death. Thus, you should wear proper gloves and a protective suit while working with such equipment. Educating your employees and creating awareness in this regard is equally essential and can help prevent a lot of accidents.
Mistake Three: Using Worn-off Materials
The use of old or corroded material can also affect the quality and performance of your work to a great extent. Worn-off equipment can lead to an increase in heat loss and might require higher energy and power to complete the welding process. So, you should carefully check your machine before working with it. We advise replacing the parts that are corroded or damaged to improve the efficiency of the tool.
Mistake Four: Failing to Prepare the Worksite
Last but not least, failing to prepare the worksite beforehand can have negative consequences on your final product as well as your health. It is essential to clean all the debris before and after the welding to ensure better air quality and increased working space. It is also recommended to ensure proper ventilation. This prevents the fumes from concentrating in one region and protects your lungs against diseases.