24-00 ELECTRICAL POWER

Transcription

1 ELECTRICAL POWER 1. GENERAL This chapter contains information on DC Generation, External Power, and Electrical Load Distribution. The airplane is equipped with a two-alternator, two-battery, 28-volt direct current (VDC) electrical system designed to reduce the risk of electrical system faults. The system provides uninterrupted power for avionics, flight instrumentation, lighting, and other electrically operated and controlled systems during normal operation. The electrical system also provides automatic switching from either battery or alternator to the Essential Bus in the event of an electrical system failure by the opposing alternator or battery. The bolster panel contains the pilot switches for operating ALT 1, ALT 2, BAT 1, and BAT 2. The switches are mounted adjoining so that a pilot can control all four switches with a single hand. Power generated from the alternators is fed into the Master Control Unit (MCU). The MCU regulates and distributes the power to the batteries and the system loads. Each alternator provides constant charging current for the corresponding battery and primary power to the aircraft electrical system during normal system operation. (See Figure ) A. Electrical Power - Serials w/o Perspective Avionics Serials thru , thru , & subs w/o Air Conditioning: Alternator 1 (ALT 1) is a gear-driven, internally rectified, 60-amp alternator mounted on the right front of the engine. Serials , & subs w/ Air Conditioning: Alternator 1 (ALT 1) is a gear-driven, internally rectified, 100-amp alternator mounted on the right front of the engine. Alternator 2 (ALT 2) is a 20-amp engine-driven alternator mounted to the aft engine accessory pad. ALT 1 is regulated to 28 volts and ALT 2 is regulated to volts. Both alternators are self-exciting (not self-starting) and require battery voltage for field excitation in order to start up. Battery 1 (BAT 1) is an aviation grade 12-cell, lead-acid, 24-volt, 10-amp-hour battery mounted on the right firewall. BAT 1 is charged from the Main Distribution Bus in the MCU. Battery 2 (BAT 2), located in the empennage, is composed of two 12-volt, 7-amp-hour, sealed, leadacid batteries connected in series to provide 24 volts. BAT 2 is charged from the circuit breaker panel Essential Bus. B. Electrical Power - Serials w/ Perspective Avionics Alternator 1 (ALT 1) is a gear-driven, internally rectified, 100-amp alternator mounted on the right front of the engine. Alternator 2 (ALT 2) is a 70-amp belt-driven alternator mounted to the left front of the engine. ALT 1 is regulated to 28 volts and ALT 2 is regulated to volts. Both alternators are self-exciting (not selfstarting) and require battery voltage for field excitation in order to start up. Battery 1 (BAT 1) is an aviation grade 12-cell, lead-acid, 24-volt, 10-amp-hour battery mounted on the right firewall. BAT 1 is charged from the Main Distribution Bus in the MCU. Serials thru : Battery 2 (BAT 2), located in the empennage, is composed of two 12- volt, 12-amp-hour, sealed, lead-acid batteries connected in series to provide 24 volts. BAT 2 is charged from the circuit breaker panel Essential Bus. Serials & subs, 22T-0001 & subs: Battery 2 (BAT 2), located in the empennage, is composed of two 12-volt, 7-amp-hour, sealed, lead-acid batteries connected in series to provide 24 volts. BAT 2 is charged from the circuit breaker panel Essential Bus. Page 1 15 Dec 2014

2 2. TROUBLESHOOTING No alternator output. (Voltmeter Indicates 24 VDC or less and the ammeter indicates a discharge when the corresponding BAT switch is set to ON position) Loose alternator wire connection. Alternator switch off. Defective alternator. Circuit breaker activated (open). Faulty voltage regulator. Low engine RPM. Tighten connector. Turn on corresponding alternator switch. Replace alternator. Reset circuit breaker and troubleshoot circuit. Replace voltage regulator. Increase engine RPM. Alternator output is low. Loose alternator wire connection. Tighten corresponding connector. Faulty voltage regulator. Faulty MCU. Faulty alternator. Low engine RPM. Replace voltage regulator. Replace MCU. Replace alternator. Increase engine RPM. No battery output. Poor battery connections. Clean and tighten connections. High water usage (Battery 1). Battery will not hold charge. Short battery life (Battery 1). Faulty battery. Alternator output high, faulty voltage regulator. Faulty battery. Flights too short to recharge sufficiently. Loose connections, corrosion. Faulty battery. Standing too long (hot climate). Electrolyte level below top of plates. Battery hold down loose. Overcharging of battery (faulty voltage regulator). Replace corresponding battery. Replace MCU. Replace battery. Remove corresponding battery and recharge when necessary. Tighten, clean, and neutralize connections. Replace corresponding battery. Remove corresponding battery and recharge when necessary. Keep electrolyte level above plates. Keep hold down secure at all times. Replace MCU. Page 2 15 Jun 2010

3 External power receptacle inoperable. Low volts light illuminates. BAT 1 switch in OFF position. Faulty ground wire/connection. Faulty ground power relay. High demand on electrical system with a low engine RPM setting. Inspect and repair ground wire/ connection at receptacle or firewall ground bus bar. Replace MCU. Increase engine RPM or load shed. Faulty logic module or current sensor. Replace MCU. Alternator is noisy. Worn alternator bearings. Replace corresponding alternator. Faulty alternator diode(s). Replace corresponding alternator. No output from alternator 2. Loose alternator wire connection. Tighten connector. Faulty alternator drive unit. Faulty alternator. Replace alternator drive unit. Replace alternator. Alternator 2 output is low. Loose alternator wire connection. Tighten connector. Faulty rectifier. Faulty MCU. Low RPM. Replace alternator. Replace MCU. Increase RPM. Oil leaks from alternator 2. Faulty oil seal in alternator. Replace alternator. Page 3 15 Jun 2010

4 Starter motor will not engage. Starter relay circuit breaker open. Reset starter relay circuit breaker. If starter relay circuit breaker opens on second attempt, check for wiring short between circuit breaker panel and MCU. Loose electrical connections between MCU and starter motor. Damaged electrical connections between MCU and starter switch. Ensure all electrical connections to starter motor are secure : At MCU, disconnect P108 and P109. Switch ignition switch to START. Verify resistance between pin E of P108 and pin B of P109 is zero. If infinite resistance is measured, check plugs, jacks, starter switch, and starter switch wiring for damage. MCU : At MCU, disconnect P137 and P135. Set ignition switch to START. Verify resistance between pin C of P137 and pin C of P135 is zero. If infinite resistance is measured, check plugs, jacks, starter switch, and starter switch wiring for damage. Starter motor power relay Remove positive cable from starter motor. Connect voltmeter to positive starter motor stud and ground. Set ignition switch to START. Verify volt meter indicates 24 volts. If system voltage reads zero, MCU starter relay Return MCU to approved factory service center for service. If system voltage reads 24 volts, replace positive terminal on starter motor and attempt to start airplane. If starter motor still does not engage, replace starter motor. (Refer to 80-10) Starter motor Replace starter motor. (Refer to 80-10) Page 4 15 Jun 2010

5 Starter motor engages when BAT 1 master switch is set to ON position. MCU starter relay welded closed. Starter motor MCU starter relay Return MCU to approved factory service center for service. Replace starter motor. (Refer to 80-10) Page 5

6 Annunciator Panel ALT 1 shows steady illumination above 2200 RPM. ALT 1 circuit breaker open : MCU current sensor Reset ALT 1 circuit breaker. shows normal currents and voltages and ALT 1 remains illuminated, replace MCU logic module. shows ALT 1 current at zero or ± 60 amps, replace ALT 1 current sensor. ALT 1 switch Serials thru : Test ALT 1 switch: Verify continuity between pin 5 and pin 7 of J660 when switch is engaged. Serials & subs, 22T-0001 & subs: Test ALT 1 switch and relay: Measure voltage between pin K of P183 and ground. If voltage does not measure volts, replace bolster switch panel : Short circuit between annunciator panel and MCU. MCU field control module Alternator 1 At MCU, disconnect plug P111. Verify ALT 1 turns off. If ALT 1 remains illuminated, a short exists within the airplane wiring. Check plug P111 and jack J111. If no shorts are found, replace annunciator panel. (Refer to 31-50) At alternator 1 with alternator cables attached, measure voltage between field input and ground. If voltage does not measure volts, replace MCU field control module. At alternator 1, measure resistance between field connector and ground. If resistance shows open circuit, alternator coil is damaged. Repair or replace alternator 1. (Refer to 24-30) Page 6

7 Annunciator Panel ALT 2 shows steady illumination above 2200 RPM. ALT 2 circuit breaker open : ALT 2 current sensor Reset ALT 2 circuit breaker. shows normal currents and voltages and ALT 2 remains illuminated, replace MCU logic module. shows ALT 2 current at zero or ± 60 amps, replace ALT 2 current sensor. ALT 2 switch Serials thru : Test ALT 2 switch: At jack J661 verify continuity between pin 5 and pin 7 when switch is engaged. Serials & subs, 22T-0001 & subs: Test ALT 2 switch and relay: Measure voltage between pin K of P182 and ground. If voltage does not measure volts, replace bolster switch panel : Short circuit between annunciator panel and MCU. At MCU, disconnect plug P111. Verify ALT 2 turns off. If ALT 2 remains illuminated, a short exists within the airplane wiring. Check plug P111 and jack J111 for damage. If no shorts are found, replace annunciator panel. (Refer to 31-50) ALT 2 field control module At alternator 2, disconnect J125. Measure voltage between one pin on jack J125 and ground. If voltage does not measure volts, replace ALT 2 field control module. Alternator 2 At alternator 2, disconnect jack J125. Measure resistance between one pin on jack J125 and ground. If resistance shows open circuit, alternator coil is damaged. Repair or replace alternator 2. (Refer to 24-30) Page 7

8 Annunciator Panel LOW VOLTS illuminated : Alternator switch MCU field control module Set BAT 1 switch to OFF position. At MCU, disconnect plug P108. Connect pin D of jack J108 to ground. If LOW VOLTS illuminates, a short exists within the airplane wiring. Check plug P108 and jack J108 for damage. If no shorts are found, replace annunciator panel. (Refer to 31-50) shows normal currents and voltages and LOW VOLTS remains illuminated, replace MCU logic module. At alternator 1 with alternator cables attached, measure voltage between field input and ground. If voltage does not measure volts, replace ALT 1 field control module. At alternator 2, disconnect J125. Measure voltage between one pin on jack J125 and ground. If voltage does not measure volts, replace ALT 2 field control module. Annunciator Panel ALT 1 flashing : MCU current sensor shows normal currents and voltages, set ALT 1 switch to OFF position. If ALT 1 continues flashing or turns off, replace MCU logic module. shows ALT 1 current at zero or ± 60 amps, replace ALT 1 current sensor. Page 8

9 Annunciator Panel ALT 2 flashing : MCU current sensor shows normal currents and voltages, set ALT 2 switch to OFF position. If ALT 2 continues flashing or turns off, replace MCU logic module. shows ALT 2 current at zero or ± 60 amps, replace MCU current sensor. Annunciator Panel ALT 1 does not illuminate when ammeter shows no current. ALT 1 circuit breaker open. Loose electrical connections at MCU : Open circuit between MCU and annunciator panel. Reset ALT 1 circuit breaker. Ensure all electrical connections at MCU are secure. At MCU, disconnect P111. Connect pin F on plug P111 to ground. If ALT 1 does not illuminate, a short exists within the airplane wiring or annunciator panel is (Refer to 31-50) shows normal currents and voltages, replace MCU logic module. Page 9

10 Annunciator Panel or ALT 2 does not illuminate when ammeter shows no current. ALT 2 circuit breaker open. Loose electrical connections at MCU : Open circuit between MCU and annunciator panel. Reset ALT 2 circuit breaker. Ensure all electrical connections at MCU are secure. At MCU, disconnect plug P111. Connect pin G on plug P111 to ground. If ALT 2 does not illuminate, a short exists within the airplane wiring or annunciator panel is (Refer to 31-50) shows normal currents and voltages, replace MCU logic module. No power when BAT 1 master switch set to ON position. BAT 1 master switch : Disconnect negative cable from battery 1. At MCU, disconnect P108. Measure resistance between pin D of jack J108 to ground. If resistance shows open circuit, test BAT 1 master switch and replace if necessary. (Refer to 31-10) MCU : Disconnect negative cable from battery 1. At MCU, disconnect plug P137. Measure resistance between pin K of J137 to ground. If resistance shows open circuit, test BAT 1 master switch and replace if necessary. (Refer to 31-10) : BAT Current Sensor Disconnect negative cable from battery 1. At MCU, disconnect plug P108. Measure resistance between pin D of jack J108 to ground. If resistance shows open circuit, test BAT current sensor and replace if necessary. Page 10

11 No external power when BAT 1 master switch set to ON position. BAT 1 master switch : Disconnect negative cable from battery 1. At MCU, disconnect plug P108. Measure resistance between pin D of jack J108 to ground. If resistance shows open circuit, test BAT 1 master switch and replace if necessary. (Refer to 31-10) MCU : Disconnect negative cable from battery 1. At MCU, disconnect plug P137. Measure resistance between pin K of J137 to ground. If resistance shows open circuit, test BAT 1 master switch and replace if necessary. (Refer to 31-10) Ammeter pegs at ± 60 amps or indicates abnormal amperage. ALT 1 circuit breaker opens during operation. ALT 2 circuit breaker opens during operation. Airplane power remains on after BAT 1 master switch set to OFF position. BAT 2 master switch set to ON position energizes non-essential equipment : BAT current sensor ALT 1 current sensor ALT 1 field control module ALT 2 field control module BAT 1 master switch MCU battery 1 power relay P109 and P115 connectors switched. Power diode shorted. Disconnect negative cable from battery 1. At MCU, disconnect plug P108. Measure resistance between pin D of jack J108 to ground. If resistance shows open circuit, test BAT current sensor and replace if necessary. Replace ALT 1 current sensor. Replace ALT 1 field control module. Replace ALT 2 field control module. Test BAT 1 master switch and replace if necessary. (Refer to 31-10) MCU battery 1 power relay Return MCU to approved factory service center for service. Plug connectors correctly. Replace power diode. Bad isolation diode on PFD, turn coordinator, or attitude indicator. Replace diode. Page 11

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