Design meets function
The new surge arresters for data line protection and measuring systems and automatic control devices from Leutron feature an interrupt-free replacement of the protection module due to their plug-in design
The seamless networking of all process areas has enormous advantages in efficiency, however, it makes the processes vulnerable: Even small disturbances in measuring systems and automatic control devices may bring the whole production out of step. It does not even need a lightning strike to trigger a disaster, even routine switching operations may generate voltage peaks that can lead to malfunctioning. In order to prevent these situations, Leutron GmbH in Germany, a specialist in surge protection, has now introduced a new series of two-piece arresters with a mechanically secure and robust latching, which were especially designed for those applications. Due to the modular design the protection module can be removed without interfering with the signal flow. The base unit which can be connected with direct or indirect shielding remains in the electric panel board. Thanks to the clamp-based wiring no attention has to be paid to different plugs and sockets when connecting. The attractive design does not only match the innovative functions, moreover, it supports them: The special tactility of the high tech material and the elevated handle moulds make the devices easy to mount and to check.
Leutron wanted the new Data arresters to have an unusual and interesting look. Thus, the designer developed a step-shaped housing with rounded corners and the contrasting colours yellow and anthracite. Nonetheless, the housing with the dimension of only a single modular width (1 DIN-size) fits into every switchgear cabinet and due to its robust metal base can be mounted on a 35 mm DIN rail. At the same time, the attractive housing serves practical aims: Not only is the applied glass fibre reinforced Polyamide PA 6.6 very resistant and durable; it provides a non-slip surface. Consistent with the durable material the arresters are laser marked. Unlike classic labels which may peel away or rub off over time the printed data stays pin-sharp and easily readable throughout the lifetime.
Impedance-neutral insertion and removal
The housing consists of two parts – like the new surge arresters: The base unit optionally can be installed with direct or indirect cable shielding. With the direct shielding the terminals 9/10 (GND) are directly connected to the metal base and the grounding. However, with an indirect shielding the terminals are connected via a gas-filled surge arrester (GDT) ensuring a galvanic insulation between the protective conductor and the cable shield. This impedes the flow of disturbing equalizing currents during normal operation. Only when an overvoltage occurs will the shielding be connected to the earth, and thus, partial lightning currents and transient surges are securely arrested.
The surge protective module which is mounted on the base unit can be inserted and removed impedance-neutrally and without interrupting the current. Therefore, performance tests and replacement can easily be carried out without disconnecting the wiring. Furthermore, the possibility to replace only the affected part saves up to half of the costs of the protective installation.
A special mechanical locking was developed to connect both components in a stable way. The locking with positive fitting pins and apertures is insensitive to shock and vibration. Unlike other locking systems which loose spring force over time this construction which is registered for patent approval is not affected by aging.
Various options for connection and application
The arrester is designed to connect one or two pairs of wire. Since the wires are directly clamped to the base unit no attention has to be paid to fitting plugs and sockets. This simplifies buying and storage. Leutron’s new Data series is suitable for all common requirements. For an adequate selection of devices Leutron offers a comprehensive application overview of interfaces.
Leutron Data is available in different configurations depending on the field of application: Devices with a high discharge capacity and low voltage protection levels or devices for high speed and frequencies that can be found in bus systems or video transmissions. The series for measuring systems and automatic control devices comprises many versions for up to 170 V DC and frequencies up to 70 MHz. Depending on the model they are suited for all transition points from LPZ 0B-1. All types are tested according to IEC 61643-21 and correspond to the degree of protection IP 20 according to IEC 60529 as well as to the fire protection classification V0 according to UL 94
Conclusion
The large variety of different configurations of the base unit and the protective module as well as the flexible connection options of the Leutron Data series allow for a highly variable application. This corresponds to the wide ranging requirements of today’s measuring systems and automatic control devices. At the same time, the modern design of the housing with its high-quality material, the robust locking and the permanent laser-marking guarantee a long lifetime of the surge protective devices (SPD) even under difficult conditions.
