NARC (N(o) ARC) circuit is designed as an add-on to relay
contacts which can be subjected to damage by switching
heavy current and/or inductive loads.
circuit needs no interfacing and does not consume power
from the circuit to which it is connected. It functions
by monitoring the rate of voltage change as contacts open
or during the 'contact bounce' of closing. When potentially
damaging levels are detected a triac device switches on
to quench any arc that might form.
have shown that, even with a highly inductive load, the
contact life approaches the mechanical life of the relay
mechanism. An additional cost saving is conferred as ordinary
gold/silver contact material may be used.
of the circuit
Gorton Electronics manufacture products there is no licensing
fee for using the patented circuit. For other manufacturers
wishing to use the technology, Gorton Electronics will
negotiate both blanket licensing agreements and royalty
NARC circuit confers significant advantages when used
in switching circuits. In that inter-contact arcing is
virtually eliminated, the operational life of contacts
can approach that of their mechanical life.
NARC circuit does not need to be changed to suit different
loads. The only stipulation is that the arc quenching
triac is able to handle the maximum load requirement which
should be the same as the contact which it is protecting.
additional bonus is that the NARC circuit will make the
mandatory European Directive on Electromagnetic Compatibility
easier to achieve in equipment as it is often the switching
arc that leads to unacceptable levels of spurious signal
radiation and conduction. Usually, it is necessary to
employ shielding and/or expensive filtering.
employment of the NARC circuit can, therefore, result
in the lowering of equipment cost and the lengthening
of service life.