Tech Insights

Fast High Energy Discharge in Xenon Flashing Beacons

December 20, 2019 by Jens Heitmann

Xenon flashing beacons manufactured by WERMA Signaltechnik GmbH use special discharge capacitors from FTCAP (part of the Mersen Group).

Flashing beacons are an important component in signal technology: they generate more attention than continuous lights, which makes them suitable for use in traffic, for example, and also in production environments. However, it takes a large amount of electrical energy to create a flash – which requires the use of discharge capacitors to meet the stringent demands of this application.

Xenon flashing beacons manufactured by WERMA Signaltechnik GmbH use special discharge capacitors from FTCAP (part of the Mersen Group).

WERMA Signaltechnik is a global leader in the manufacture of audio signal devices for warning, guiding, and protecting people around the world. The company’s solutions create safe working conditions and efficient processes – at mechanized or manual workplaces, in factories, and in buildings. WERMA offers a comprehensive portfolio from signal columns to signal beacons, horns, and sirens – products that have withstood the test of time in industrial environments, logistics and building services engineering.


Flash Signals for Traffic Safety

But WERMA products are also used in traffic systems – for example, the modified flashing beacon 828 is specially designed for use in road tunnels. This is especially important for the safety of tunnel users in the event of an accident in the tunnel. In such a scenario, a clearly marked escape route can save lives. For this reason, the green emergency exit signs are additionally equipped with a clear flashing beacon, and the blue emergency call signs with a yellow flashing beacon. These highly visible beacons of the 828 series from WERMA safely and reliably indicate the nearest escape route to provide orientation especially in the case of smoke build-up. The xenon flashing beacon 828, specially developed for overhead mounting, carries an IP 65 rating. In addition, a special pressure compensating valve on the crown prevents condensation from forming inside the beacon. This rugged design can even withstand the effects of tunnel cleaning.


Figure 1: Xenon flashing beacons manufactured by WERMA Signaltechnik GmbH use special discharge capacitors from FTCAP (part of the Mersen Group)


“Flashing beacons, however, are also used in many other scenarios – in general, wherever a signal device has to generate a high level of attention”, explains Michael Groll, Head of Marketing WERMA Signaltechnik GmbH + Co. KG. “That is why our product portfolio includes numerous beacons with the so-called xenon flash.” The xenon flashing beacon is used widely in signal technology. It consists of a glass tube that is filled with the inert gas xenon. Such a flash tube is generally connected to a capacitor. If the capacitor has a sufficiently high voltage and quantity of charge, the ignition of the flash tube generates an electric arc, which causes the capacitor to discharge.


Xenon Flashing Beacons with Specially Designed Capacitors

The capacitor, therefore, stores the energy required for the flash pulse, which is perceived during the discharge as a short and intensive flash. Storage of the power required for the flash is currently possible only with aluminum electrolytic capacitors. But the standard models are not sufficient, due to the fast discharge and pulse sequence: special discharge or flash capacitors are needed. “However, we not only wanted to create a heavy-duty capacitor but also a solution that can withstand continuous operation”, Michael Groll emphasizes. “The core requirement was therefore that the capacitor must withstand the sustained loads of flash applications between 0.7 and 1.7 Hz. In addition, we needed a high switching capacity.”

Discharge capacitors are included in the product range of FTCAP – the capacitor manufacturer, part of the Mersen Group since 2018, offers numerous versions of these special products. In close coordination between the customer and manufacturer, the choice fell to the two types AE22035012030 and LSEH47035016039. “The letter E in our type designations stands for the German word for discharge capacitors”, explains André Tausche, Managing Director of FTCAP. “The AE type is an axial flash capacitor that we deliver as a taped component. The LSEH type features a so-called soldering star as the terminal. The soldering star conducts the current from the winding through the case to the negative contact.”


Fully Welded Discharge Capacitors from FTCAP

In flash applications – such as professional flash devices in photo studios or radar speed traps – capacitors discharge very quickly. The main requirements for flash capacitors are high energy per volume values, compact dimensions, and a maximum flash frequency. The aluminum foils developed by FTCAP and its suppliers especially for this purpose make it possible to produce aluminum electrolytic capacitors with a high capacity-voltage (CV) product. Their fully welded design allows them to withstand constantly changing temperatures with no compromises. This also minimizes contact resistance, which ensures long-term stability. The high switching capacity of these electronic components is especially advantageous in flash applications with very short discharge times. This makes them ideal for a wide range of applications besides flashing beacons: FTCAP capacitors prove themselves in numerous applications, from hair removers to aircraft wing lights, flashing lights in wind turbine towers, and even radar speed traps.


Figure 2: The FTCAP product range includes numerous versions of discharge capacitors


There are very few companies that manufacture the capacitors needed in our xenon flashing beacons”, concludes Michael Groll. “We have a niche that is served very well by FTCAP. We are satisfied with the company’s products and service – especially with respect to advice.” All the signs, therefore, point toward a green light for continued cooperation between the two partners.


About the Author

Jens Heitmann worked as an account manager/marketing manager at FTCAP GmbH that has more than 70 years of experience in the development and production of capacitors used in diverse industries. The product spectrum includes both film and aluminum electrolytic capacitors. The company is one of the few manufacturers who still produce all of its products in Germany – for quality reasons. Short distances between development and production ensure efficient processes and enable close coordination with our customers.