TM 9--2350--292--20--10165 00--1WARNING SYSTEM OVERVIEW AND DIAGRAMS.0165 00THIS WORK PACKAGE COVERS:Warning System Overview And DiagramsThe warning system is comprised of the following electrical circuits; SYSTEM WARNING light and warning horn,PTO clutch high oil temperature warning light, low brake pressure warning light, and lamp test. In addition, thewarning system also monitors the winch electrical system to detect winch malfunctions.The SYSTEM WARNING light and warning horn electrical circuits consists of the SYSTEM WARNING light, warn-ing horn, transmission high oil temperature switch, engine low oil pressure switch, engine high oil temperatureswitch, two diode assemblies, low brake pressure relay, winch warning relay, horn relay, HORN OVERRIDE switch,15--amp circuit breaker, and related electrical wiring.When the MASTER switch is turned ON, the SYSTEM WARNING light will normally come on until the main engineis started and running. Initially, the warning horn will not sound; however, as the engine is started and normal gen-erator voltage output (+28 V dc) is produced, the horn may sound briefly until engine oil pressure reaches normaloperating range. At this point both the warning light and the horn are turned off. With the engine running, both thelight and the horn will come on if either of the following conditions occur: engine oil pressure drops below 9 psi,engine oil temperature rises above 245_ F, transmission oil temperature rises above 285_ F, brake pressure fallsbelow 475 psi, hydraulic system PTO clutch oil temperature rises above 285_ F, or a fault is detected in the mainwinch electrical system.When the MASTER switch is ON, system power (+24 -- 28 V dc) to operate the SYSTEM WARNING light is sup-plied from the switch panel. The warning horn receives supply voltage (+28 V dc) from the main engine generator;thus, the main engine must be running for the warning horn to sound. High engine oil temperature and low engineoil pressure are detected by engine mounted switches. Likewise, high transmission oil temperature is detected bya switch mounted in the transmission. In either case, exceeding the temperature or pressure limit causes theswitch contacts to close providing a ground for the SYSTEM WARNING indicator and horn relay. As a result, theindicator circuit is complete and the SYSTEM WARNING light is lit. The ground at the horn relay energizes therelay and completes the horn circuit to sound the horn.The PTO clutch high oil temperature indicator circuits consist of the HIGH TEMP indicator, the PTO high tempera-ture switch, a 15--amp circuit breaker, and related electrical wiring.When the MASTER switch is ON, the HIGH TEMP indicator is lit whenever PTO clutch oil temperature exceeds285° F. System power (+28 V dc) is supplied to the HIGH TEMP indicator through the 15--amp circuit breaker inthe hydraulic control panel. The PTO high temperature switch is mounted in the PTO clutch assembly and, whenthe oil temperature reaches 285°, the switch closes. As a result, a ground is applied to the indicator to completethe circuit and light the indicator. The switch ground is also applied through an isolation diode to the SYSTEMWARNING LIGHT and warning horn circuits; thus, with the main hydraulic system in operation, the warning hornwill sound and the SYSTEM WARNING light will be lit.The low brake pressure warning light electrical circuits consists of the LOW BRAKE PRESSURE warning light, lowbrake pressure switch, and related electrical wiring.When the MASTER switch is turned ON, the LOW BRAKE PRESSURE warning light comes on whenever the hy-draulic brake pressure falls below 475 + 25 PSIG (old configuration) or 550 + 25 PSIG (new configuration withbrake modulation). The low brake pressure switch detects the low brake pressure condition and the switch con-tacts close. System power (+24 -- 28 V dc) is applied through the closed switch contacts to light the LOW BRAKEPRESSURE warning light and the low brake pressure relay. With the low brake pressure relay energized, a groundis supplied to the SYSTEM WARNING light and warning horn circuits. With the main engine in operation, the SYS-TEM WARNING light comes on and the warning horn sounds.The warning system monitors the winch electrical system to detect level winder drum malfunctions and the payoutlimit of the main winch wire rope. The LEVEL WINDER MALFUNCTION indicator lights if an improper alinement ofthe wire rope is detected, Likewise, the WINCH DRUM MALFUNCTION indicator lights if an irregular wrappingsequence onto the winch drum is detected. The PAYOUT LIMIT indicator lights if less than four wraps of the wirerope remain of the main winch drum. When any of these conditions are detected, main winch operation is automat-ically shut down and the SYSTEM WARNING light is lit.
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