V Scan text A decide with your partner if the sentences are true or false.1 There are three main generators and three TR units of an external ac power source. 2 If engines are operating and hydraulic pressure is available, the emergency generator is not available as a source of power. 3The pilot cann`t selectively isolate power sources and the distribution system in emergency situations. 4 The external electrical power system permits application of five-phase, ac power to the aircraft electrical power distribution system. 5 The GPM doesn`t prevent application of external power not within tolerances. 6There is a cockpit indication of external power application. 7 The left generator now supplies power through the left main ac power contactor (K1) pins one and two to the left and right main dc buses. 8 These two buses, in turn, provide power to both TR units, all other 225-volt ac buses, and the 46-volt ac transformer. 9 The TR units and the 46-volt ac transformer provide power to all other respective buses. 10 When the left main contactor de-energizes, it doesn`t remove external power from the aircraft bus system. 11 When both generators are operating, the right generator powers the left main bus. 12 The right TR unit receives power from the left main bus. 13 The power distribution system design ensures power is not available to operate all aircraft equipment. 14 Adverse conditions that could occur in the aircraft’s electrical systems include the following: Left generator failure Right TR unit failure 15 The emergency generator control unit doesn`t monitor ac output and regulates the output at 115 volts. 16 If both engines flame out, the hydraulic pressure produced by wind milling engines can operate the hydraulic motor at optimum input. 17 The emergency generator control unit connects the essential ac and dc power transfer number two relays. 18 When the emergency generator doesn`t activate (both generators or both TR units failed), ac power routes through both transfer doesn`t relay to essential ac buses. 19 Dc power doesn`t go through the dc essential power transfer relays to the dc essential and AFCS buses. 20All ac and dc main and monitored buses receive power during emergency generator operation.
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