Capacitors - ELECTRONICON Safety of the Capacitors - Thermal Fuse: More Safety for Lighting Capacitors

Safety of the capacitors

1. Self-healing Dielectric
All dielectric structures used by ELECTRONICON are "self-healing":
In the event of a voltage breakdown the metal layers around the breakdown channel are evaporated by the temperature of the electric arc that forms between the electrodes. They are removed within a few microseconds and pushed apart by the overpressure generated in the centre of the breakdown spot. An insulation area is formed which is reliably resistive and voltage proof for all operating requirements of the capacitor.
The capacitor remains fully functional during and after the breakdown.

2. Protection against Overload and Failure at the End of Useful Service Life Overpressure safety mechanism ("Break Action")
In the event of overvoltage or ageing at the end of the capacitor's useful service life, an increasing number of self-healing breakdowns may cause rising pressure inside the capacitor. To prevent it from bursting the capacitor is fitted with an obligatory "break action mechanism".
This safety mechanism is based on an attenuated spot at one of the connecting wires inside the capacitor. With rising pressure the case begins to expand, mainly by opening the folded crimp and pushing the lid upwards.
As a result, the prepared connecting wire is separated at the attenuated spot, and the current path is interrupted irreversibly. Thermal fuse (text from catalogue Lighting capacitors)

3. Pressure Switch
Capacitors in rectangular case are delivered with an overpressure switch signalling when a certain internal pressure has been reached. An appropriate safety circuit must be installed to disconnect the capacitor immediately.

Thermal Fuse: More Safety for Lighting Capacitors

ELECTRONICON offers a new and well-proven technical solution based on the principle of thermal disconnection. By using a new design of thermal fuse characterized by its irreversible and reliable disconnection features we have eliminated any risk of eventual failure so typical of comparable competitive solutions.

thermal fuse The new design offers the following advantages:

absolutely reliable disconnection of the capacitor in case of failure
insensitive to external mechanical influence
no mechanical factors affecting the fuse function as is the case with conventional disconnection devices (e.g. thickness of capacitor case, thickness of break-action wire, strength of connecting leads, stability of the lid, moving contact parts etc.)
almost no ageing effects

A sophisticated, patented system melts the fuse element within the fuse body when a critical temperature is reached. The element melts into small open globules which are completely insulated from each other not only by the distance but also by a special insulating compound which appears at the point of meltdown.

The thermal disconnection is resistant to surge currents within the permitted range of capacitor current. The applied fuse system is approved to UL, CSA and VDE.

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