What are Taps on a Welding Transformer?

Welding transformers are a go-to accessory for regular as well as resistance welders. These units help convert AC voltage from the power source into the optimum voltage required for welding.

Thus, leading to the formation of a welding arc. Taps are specialized items on top of secondary coils in the transformers mentioned above and aid in regulating 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 taps on a welding transformer, its configuration, location, and impact on the design.

What is Welding Transformer

Before we get into the details of tapes on a welding transformer, it is essential to identify the welding transformer. Like common transformers used to regulate the AC current and voltage supplied to the final consumer, welding transformers regulate 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, 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 more than seven taps.

Primary wires have 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.

Welding transformer design
Image Source: Howtoresistanceweld

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 convert DC voltage to AC voltage. In addition, manufacturers also recommend adding a conductor to the device to smoothen the current and the output.

What Are the Taps on a Welding Transformer

Working Mechanism

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 easy to form.

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 reduced ion generation, which impacts the overall performance and results later. Thus, experts advise that the recovery time should be kept as low as possible to maintain the arc balance.

There are various methods to decrease the recovery time, the 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 voltage adjustment, which helps decrease the recovery time. All of this, on the whole, leads to the production of additional ions to maintain the welding arc.

Low voltage hurts the performance of the cathode and can also lead to heat loss 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, achieved at a 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, taps are installed inside a transformer to regulate the voltage and maintain it within permissible limits to avoid such accidents.

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 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 without 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 the taps changes, and their location corresponds to the desired voltage on the phase terminal.

In the case of winding transformers, the taps are 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 capable of generating a high current. This equips them to decrease the voltage when required.

These units can regulate 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. 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, increased heat production is witnessed in large welding transformers due to high resistance between electrodes and welding pieces.

These units have multiple phase inputs and are more prone to arc impairment. So, the role of taps becomes even more prominent in such tools 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 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 consumers make.

Common Mistakes Made While Using the Taps

Mistake One: Use of Wrong Tape Size for Different Applications

There are various sizes of taps available in the market. Each of these 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 and use M12* 50, which might not work 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 for which size of tape is compatible with the object you will weld.

Mistake Two: Negligence in Safety

Another common mistake most users commit is negligence in the safety procedure while installing and working with welded transformers. Lack of preventive measures poses a potential electric shock, injury, and burn risk. 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 corroded or damaged parts to improve the tool’s efficiency.

Mistake Four: Failing to Prepare the Worksite

Lastly, failing to prepare the worksite beforehand can negatively affect your final product and 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.

Frequently Asked Questions

How do taps help in adjusting the voltage?

Taps are connected to the secondary coil in different arrangements and work together with jumpers to regulate the voltage. The end of the tap line is often connected with one or more terminals.

Based on the line voltage, taps help increase or decrease the AC voltage to produce a voltage arc. Thus, protecting the cathode against temperature variations and ensuring the optimal performance of a welding transformer.

How to determine the best setting for the tap?

AC welding is characterized by excessive heat generation, especially in transformers with multiple phase inputs. So, it is recommended by experts to decrease the recovery time to a significant extent to ensure efficient results.

To do so, selecting a tap that can maintain an optimum voltage level while welding is important. Mostly, the lowest tap is used at a higher current value to increase the voltage in a short time. However, taps are not solely responsible for increasing the voltage.

Instead, these items also help maintain the voltage under permissible levels and prevent it from rising to dangerous levels. It is advised to keep the tap at the optimal setting, as mentioned above, to ensure better performance in the long term.

What are tap switches and turns?

The tap switch is located on top of the tap and is associated with changing the turn ratio of a transformer. This change contributes to the change in overall voltage and affects the current distribution in different parts of the device.

The turn ratio is very important in this regard. It allows the tap to reach the desired voltage. For better functioning, the turns should be kept at 7 or 12. A slight increase or decrease in the number of turns can dramatically impact the overall abilities of the transformer.

Final Words

Taps play a significant role in maintaining the voltage arc of a welding transformer. These items can increase and decrease the voltage as per requirement and contribute to the prevention of arc impairment. Connected in multiple configurations, the taps greatly impact the design and performance of the transformer.

Therefore, they must be selected carefully to prevent accidents or performance inefficiency. The switch located over the taps helps turn the voltage, leading to a change in current. The turns are extremely important, and a slight change in turn ratio can impact the overall result of the welding operation.

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Dave Walker is a skilled welder and passionate blogger. With years of experience in welding, he has honed his craft and developed a deep understanding of the trade. In his blog, he shares his experiences, insights, and tips on welding, offering a valuable resource for fellow welders and those interested in the field. He is dedicated to promoting the importance of welding and its applications in various industries.