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1. PRECISION CONTROLS: Due to certain design features PORTEX-UNIGUARD circuitbreakers operate within overloads of less than 25%. Throughout the world the industry standards of various manufacturers of thermally operated circuitbreakers specify a "must trip" point of 35% overload or more. Our devices are calibrated to carry rated current continuously but "must trip" within overload of 1% to 25% at 35C ambient.
2. TRIPPING MECHANISM: The bimetallic switching mechanism employed has proved extremely reliable as it is a sophisticated overcentre mechanism.
3. NO MECHANICAL LATCHING: Unlike other circuit breakers, there is no mechanical latch for holding the contacts in the closed position. In our device the contacts stay in the closed position due to the over-centre bi-metalic mechanism, which snaps the contacts to the open position when the bimetals heat up and change the over-center angulation. Hence the problems of unreliability due to latch wear-out and change in latch release friction characteristics are avoided.
4. HEATER SYSTEM: In conventional circuitbreakers a heater element is wound round a bi-metal strip with an intervening layer of mica or other high temperature insulation. As a result of this the following malfunctions are likely in conventional circuitbreakers.
(a) Failure of insulation between bi-metal and heater
(b) Failure of heater element as it has to flex continuously along with flexing of the bi-metal during operation
(c) Failure of heater element because a sufficiently thick element cannot be used as it has to flex along with the bi-metal strip.
All these problems are eliminated in our patented mechanism as the heater section is separated from the tripping section by an air gap. So there is no insulation failure between bi-metal and heater. Further, the heater element is rigid and does not move when the bi-metal moves. Thus a very thick and failure proof heater element is employed. Due to the above reasons a PORTEX circuitbreaker is highly accurate, reliable and long lasting.
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