General
Norm	EN 61643-11
Degree of protection	two-pole
Protection voltage	30 V
Technology	Zinc oxide varistor / spark gap combination
System	DEHNrail modular
Application range	control cabinets, industrial electronics
Application	lightning protection zone concept, interfaces 1-2 and higher

The DEHN surge arrester type DR M 2P 30 FM is a two-pole, modular protection device of the brand DEHN, specifically designed for use in enclosures of industrial electronics. The device protects the power supply of sensitive electronic equipment against transient overvoltages caused by lightning strikes, switching operations, or other electrical disturbances. It is a surge arrester of Type 3 category according to the standard EN 61643-11, integrated into the lightning protection zone concept, and can be used at interfaces 1 to 2 and higher. The construction consists of a base element and an inserted protection module, enabling flexible and modular mounting.

Applications

The arrester is intended for use in industrial environments, particularly in enclosures where electronic controls, frequency converters, PLC systems, or other sensitive devices are connected to the power grid. It protects these devices against short-term voltage spikes caused by external influences such as lightning discharges or internal switching operations in the network. The application is part of a multi-stage lightning protection concept, where this arrester serves as the third stage (Type 3) installed directly before the device to be protected.

Functions and Equipment in Detail

The arrester features a high surge current capacity, achieved through a combination of zinc oxide varistors and spark gaps. This technology enables a rapid response to overvoltages and efficient dissipation of energy to protect connected devices. The modular design allows for easy integration into existing enclosure systems, especially in combination with the DEHNrail system. The two-pole configuration covers the protection function for two conductors, typically phase conductors in a three-phase system or lines in a single-phase system.

Technology Explained Simply

Zinc oxide varistors react to voltage spikes by suddenly becoming conductive when a certain threshold voltage (here 30 V) is exceeded, thereby diverting excess energy. The spark gap complements this function by serving as an additional discharge path during high energy absorption. The combination of both elements ensures a robust and reliable protection function. The protection voltage of 30 V is suitable for applications in industrial electronics, where operating voltage is often below 50 V, for example in control systems or sensors.

Compatibility and Accessories

The arrester is part of the DEHNrail modular system and can be combined with other components of this system to realize a comprehensive protection concept. It is designed for use in enclosures and fits into the standard module track of the DEHNrail platform. It is used in conjunction with other surge protection devices installed in the previous protection stages (Type 1 and Type 2) to form a complete protection chain.

Mounting and Installation

Mounting is done by inserting the protection module into the base element, which is attached to the DEHNrail module track. Installation is carried out directly before the device to be protected, with electrical connections performed according to regulations and the specific installation. The modular design enables quick and secure mounting without additional tools.

Advantages in Operation

The arrester provides reliable protection for sensitive electronic devices in industrial installations. The modular construction facilitates maintenance and replaceability, while the combination of zinc oxide varistor and spark gap ensures high efficiency in diverting overvoltages. Compliance with the standard EN 61643-11 ensures conformity with applicable safety standards for surge protection devices.