AC Line Surge Protectors
Type 1 surge protection devices are combined lightning current and surge arresters that are used in unmetered areas. They are meant to protect against the effects of direct lightning strikes and must satisfy very stringent requirements. In order to meet these requirements, spark gap technology is required. A spark gap will break down during an abnormal voltage surge, safely shunting the surge to ground.
Type 2 surge protection devices with a low discharge capacity are installed in the metered area. They are generally installed in machine control cabinets or sub-distributions. They do not have to handle direct lightning strikes, but they must be able to discharge over-voltages from indirect lightning strikes or switching operations. Varistor technology is proven itself here. At low voltage, the varistor has a high electrical resistance which decreases as the voltage increases. When an over-voltage occurs, the varistor’s resistance drops, allowing the extra current to flow through the varistor and safely to ground.
Type 3 surge protection devices with the lowest discharge capacity are installed as close as possible to the end device. The devices have a wide range of designs to suit the various different installation environments. Type 3 surge protection is similar to type two, which is based on varistors, but the requirements concerning discharge capacity are lower compared to type 2.
Phoenix Contact AC Line Surge Protection
Raycap AC Line Surge Protection
Schneider Electric AC Line Surge Protection
Transtector AC Line Surge Protection
More Information about AC Line Surge Protectors
Power surges occur when there is a sudden increase of voltage sent through a power system from an internal or external force. Such forces can be caused by lightning strikes, electrical overload, faulty wiring or utility switching. Surge protection devices provide a line of defense against power surges preventing irreparable damage to equipment and costly downtime. Surge protection devices are generally classified according to their performance values, depending on the protection class and location of use.
Surge Protection Basics
What causes power surges?
Lightning strikes are one of the most common causes of power surges and can affect an electrical system even if the strike occurs miles from the electrical source. Conductors buried underground can still transmit the energy of the strike to electrical equipment located indoors. Lightning rods and other grounding equipment can help, but do not completely eliminate the risk.
Switching equipment such as motors, transformers and other equipment can cause a sudden change in load, power loss and disconnection of circuit breakers. This sudden switching can cause overvoltage, leading to power surges. The closer the switching occurs to the electrical system, the more threat it will pose to the equipment.
Operations that a user performs can cause surges, but typically have a very short duration. Examples include: starting a motor, opening circuit breakers and welding equipment.
What is the best way to stop power surges?
By using transient surge suppressors, the problems associated with most transient surges can be eliminated. They provide protection by either blocking or shorting the voltage over its operating limit to ground, protecting circuits downstream of the suppressor. The best way to approach this is in tiers.
Tier 1 – The protection is closest to the incoming power source. This is the main protection for a particular location.
Tier 2 – This is in an area that will be protecting multiple devices that have branch protection. An electrical control panel would be an example of this type of application.
Tier 3 – Individual protection. In the case of an industrial control panel, this would be protection for each instrument entering the panel.