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Unformatted text preview: the points in the engine nacelle where temp is highest. These switches using bimetallic thermo switch closes when the temperature is above the preset temperature. When the switch closes it brings warning light with alarm. When test s/w is put on, test relay energized shifts the contact they bring light on. 1. 2. 3. 4. When dimming relay is energized red light will be dim. Two terminal spot type fire detection system that uses individual thermo switches installed around the inside of the area to be protected. These thermo switches are wired in parallel between two separate switches. A short or an open circuit can exists in either circuit without causing a fire warning. THERMO COUPLE TYPE (RATE OF TEMPERATURE RISE): Also Edison fire detection when two dissimilar metals such as chromyl and constant a jointed will be exposed to heat or fire (hot junction) forms thermo couple. This system operating on the rate of temperature rises principle (It does not operate when engine over heat slowly or short circuit develops). Relay box consists of t...
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