Overpressure disconnector
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Electrical components do not have unlimited life expectancies; this also applies to self-healing
capacitors. As polypropylene-type capacitors seldom produce a pronounced short circuit, HRC
fuses or circuit breakers alone do not offer sufficient protection.
All capacitors of the PhaseCap Premium, PhaseCap Compact, PhaseCap , PhaseCap HD,
DeltaCap and PhiCap series are consequently fitted with a disconnector that responds to
overpressure. If numerous electric breakdowns occur at the end of life or as the result of thermal
or electric overload (within IEC 60831 specification), the formation of gas causes the pressure
inside the capacitor case to rise.
This causes a change in length because of curvature of the lid or stretching of the expansion
bead. Expansion beyond a certain degree will separate the internal wires (tear-off fuses) and
disconnect the capacitor from the line.
CAUTION
The function of an overpressure disconnector can be affected.
To ensure full functionality of an overpressure disconnector, observe the following
requirements:
1. The elastic metal top must not be impaired.
• The connecting lines must be flexible leads (cables).
• There must be sufficient space for expansion above the connections (stated for the
different models).
• The folding groove must not be retained by clamps.
2. The maximum allowed fault current of 10000 A to the UL 810-standard must not be
exceeded.
3. Stress parameters of the capacitor must be within the IEC 60831specification.
Installation and maintenance instructions for Power Factor Correction (PFC) capacitors
Installation Manual, 05/2022, L1V30884033A
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