The electric arc phenomenon can damage electrical equipment and is dangerous for operators, but not everyone knows about its origin, harm and how to prevent it. Let's learn about what an electric arc is and the application of this phenomenon with An Nhien.

I. What is an electric arc?

An electric arc, a form of Plasma, is a self-discharge process that occurs in a gas at normal pressure or low pressure between two electrodes with a small voltage, often accompanied by heat and strong light.

In an electric arc, the current running through the gas between the two poles is mainly a flow of electrons (and negative ions) going from the cathode to the anode, but there is also a part of a flow of positive ions going in the opposite direction. When electrons and negative ions collide with the anode, the anode heats up, causing the temperature to reach 3500 degrees Celsius, emitting electric sparks and strong light.

II. Generation process and method of extinguishing electric arc

The process of generating an electric arc and the method of extinguishing it both require specific conditions and methods to ensure safety.

Electric arc generation process

To create the electric arc phenomenon, the following two conditions must be satisfied:

 

1. Increase the temperature of the two electrodes to a level where a large number of electrons can be emitted through thermionic emission.
2. Create a strong enough electric field between the two electrodes to ionize the gas between the two electrodes and create a number of free electrons. At that time, the gas environment becomes a conductive environment between the two electrodes and generates an electric spark.

 

Generation process and method of extinguishing electric arc

Quenching process

This process requires the opposite conditions to the process of electric arc generation, specifically:

– Reduce or cut off power:

 

• Circuit Breaker: Use automatic circuit breakers such as fuses or circuit breakers to cut off the current as soon as an arc is detected. Circuit breakers use springs or magnets to quickly pull the contacts apart, reducing the current and extinguishing the arc.
• Reducing the voltage: Reducing the voltage applied to the system can reduce the energy of the arc and help extinguish it.

 

– Increase the distance between the electrodes: As the contacts move further apart, the distance of the arc increases, reducing the current density and making the arc more susceptible to extinguishment due to loss of energy.

– Using arc extinguishing medium:

 

• Insulating liquid: Insulating oil is commonly used in transformers and oil circuit breakers to extinguish the arc. When an arc occurs, the oil vaporizes and creates an insulating gas layer, preventing the arc from continuing.
• SF6 gas: Sulfur hexafluoride (SF6) is a highly effective insulating gas, commonly used in high-voltage switchgear. SF6 has excellent arc extinguishing properties due to its ability to absorb energy and create a non-conductive environment.
• Vacuum: In a vacuum environment, there are no gas molecules to ionize, making it impossible to maintain an arc.

 

III. Harmful effects of electric arc phenomenon

The harmful effects of electric arc phenomenon can be listed as:

 

1. Equipment and machinery destruction: Arc flash can cause damage and destruction to controls, machinery, and other equipment due to sudden changes in voltage and local system interruptions.
2. Risk of injury and death: Arc flash can cause equipment to explode, leading to the risk of injury and death to people working near the scene.
3. Reduced productivity: Equipment and machinery damaged by arc flash can reduce productivity, negatively impacting the production activities of the enterprise.

 

Harmful effects of electric arc phenomenon

4. Repair costs: Businesses have to pay a large amount of money to repair electrical equipment damaged by arc flash.

IV.Applications of the electric arc phenomenon

 

1. Electric welding: In the welding process, the welding rod acts as one of the two poles of this phenomenon. The other pole, usually the metal plate to be welded. The welding rod will be melted at high temperature due to the arc phenomenon and fill the position to be welded on the metal plate. Electric welding is often used in mechanical engineering, machine manufacturing, automobile manufacturing, etc.
2. Steel and iron smelting: Applied in the steel and iron manufacturing industry to create the high temperature necessary for the metal smelting process.
3. Metal fabrication: Used to melt metals and create final metal products in the fabrication process.

 

Applications of the electric arc phenomenon

Thus, the electric arc phenomenon has many important applications in industry and metal production.

V. Some protective products to prevent the harmful effects of electric arc phenomenon

Below are some popular arc flash protection products on the market such as:

Arc flash suit

Portwest FR80 Arc Flash Suit meets IEC 61482-2 standards. Using Bizflame fabric (99% cotton and 1% carbon fiber) provides resistance to fire, heat, sparks, chemicals, arcs and static electricity. High collar and flap pockets ensure maximum protection.

The 5-44 cal/cm2 Arc Flash Suit is designed with multiple layers for breathability and sweat absorption. Includes hat, mask, shirt, pants, gloves, shoe covers and jacket for safety and comfort. Using high quality materials with arc flash protection, insulation, fire resistance to prevent the effects of high temperatures and the risk of electrical shock.

Arc Flash Gloves

Portwest Arc Grip A780 Arc Flash Gloves are cut resistant and protect against welding spatter caused by arc flashes. 13-gauge cut-resistant D-rated liner made from flame-retardant aramid. Flame-retardant neoprene palm for excellent grip. Arc flash protection level 2 (ATPV 9.5 cal/cm²) meets ASTM F2675-13 Class 2

Some protective products to prevent the harmful effects of electric arc phenomenon

Arc flash helmet

The Salisbury Arc Flash Helmet protects the head and face from the effects of arc flashes. Experts recommend using it with protective clothing for comprehensive protection. This helmet will prevent harmful arc flashes from damaging the head and face.

The Onyx2 Blanc helmet is a safety helmet with a glass outer shell made of ABS plastic, the inner layer is equipped with a face shield, to protect against electric arcs and molten metal. The helmet has a 6-point harness made of Polyester material, meeting safety standards for glasses and safety helmets.

Solder mask

In addition to clothing and gloves, welding masks are also important protective equipment in the welding industry, helping to protect workers' eyes and faces from harmful effects during welding and prevent electric arcs. Some products such as Delta Plus electronic welding mask, Portwest welding glasses, Blue Eagles welding mask, handheld welding mask, etc.

VI. Summary

Electric arc is an electrical discharge process that can bring both benefits and harm to equipment, machinery and people during the working process. Contact An Nhien Company immediately to equip yourself with safe protection products against electric arc.