Dash8-Q400 Electrical PDF

Dash8 - Q400 - Electrical 12.5 12.5.1 (ATA 24) ELECTRICAL POWER Introduction The Electrical Power Generation and Distribution System (EPGDS) is used to supply the electrical energy for all onboard electrical equipment. The EPGDS has DC and AC generating systems. The DC generation system includes...

Dash8 - Q400 - Electrical 12.5 12.5.1 (ATA 24) ELECTRICAL POWER Introduction The Electrical Power Generation and Distribution System (EPGDS) is used to supply the electrical energy for all onboard electrical equipment. The EPGDS has DC and AC generating systems. The DC generation system includes a battery system. The EPGDS provides for energy conversion, distribution, storage, control, protection, monitoring, and indication to the flight crew. Provision is made for external connection of DC or AC external power while on the ground. 12.5.2 General The DC generation system is supplied by three NiCad batteries, two engine driven starter/generators, two Transformer Rectifier Units (TRUs) and an optional Auxiliary Power Unit (APU). The TRUs supply 28VDC and are powered by two engine driven Alternating Current (AC) generators that supply 115Volts Alternating Current (VAC). The power is distributed by an electrical bus system. It re configures for individual power source and bus failures, by the automatic closing and opening of bus tie contactors. There are both DC and AC external power receptacles for Ground Power Unit (GPU) connection. All AC and DC aeroplane services can be operated from the AC generators or the AC external power alone. Page 1 Dash8 - Q400 - Electrical 12.5.3 Controls and Indications - Electrical Power Page 2 Dash8 - Q400 - Electrical 1 PFD NAV SYS ENG MFD1 1 NORM 2 ELEC SYS ENG SYS FUEL SYS DOORS SYS ALL TEST ED BRT NAV SYS PFD ENG MFD2 1 NORM 2 EFIS ADC SOURCE EFIS ATT/HDG SOURCE OFF Figure 12.5-1 Engine and System Integrated Displays Control Panel (ESCP) ESCP CALLOUTS PERTAINING TO ELECTRICAL ITEMS 1. ELEC SYS PUSHBUTTON (momentary action) PUSH - provides a display of the electrical system page on the MFD (upper area) with MFD 1 or MFD 2 set at SYS - there is no action with another push Page 3 Dash8 - Q400 - Electrical 1 2 3 DC CONTROL OFF OFF AUX BATT STBY BATT GEN 1 MAIN BATT OFF OFF OFF OFF OFF BATTERY MASTER OFF OFF GEN 2 MAIN BUS BUS FAULT EXT PWR RESET TIE Figure 12.5-2 DC Control Panel (1 of 3) Page 4 Dash8 - Q400 - Electrical DC CONTROL PANEL CALLOUTS 1. STBY BATT switch (two position) STBY BATT - left main feeder bus charging circuit connected to standby battery - EPCU logic inhibits this connection under the following conditions: • with external power (no charge) option • when a DC bus fault is present on the left main feeder bus • during emergency operations OFF - disconnects standby battery from left main feeder bus - STBY BATTERY caution light turns on any time the standby battery is not connected to the left main feeder bus 2. AUX BATT SWITCH (two position) AUX BATT - left main feeder bus charging circuit connected to auxiliary battery - EPCU logic inhibits this connection under the following conditions: • with external power (no charge) option • when a DC bus fault is present on the left main feeder bus • during emergency operations OFF - disconnects auxiliary battery from left main feeder bus - AUX BATTERY caution light turns on any time the auxiliary battery is not connected to the left main feeder bus 3. MAIN BATT SWITCH (two position) MAIN BATT - right main feeder bus charging circuit connected to main battery - EPCU logic inhibits this connection under the following conditions: • with external power (no charge) option • when a DC bus fault is present on the right main feeder bus • during emergency operations OFF - disconnects main battery from right main feeder bus - MAIN BATTERY caution light turns on any time the main battery is not connected to the right main feeder bus Page 5 Dash8 - Q400 - Electrical 4 DC CONTROL OFF OFF AUX BATT STBY BATT GEN 1 MAIN BATT OFF OFF OFF OFF OFF BATTERY MASTER OFF OFF GEN 2 MAIN BUS BUS FAULT EXT PWR RESET TIE 5 6 7 Figure 12.5-3 DC Control Panel (2 of 3) Page 6 Dash8 - Q400 - Electrical DC CONTROL PANEL CALLOUTS (cont’d) 4. BATTERY MASTER SWITCH (two position, lever locked at OFF) BATTERY MASTER - any battery is capable of powering both essential buses - switch control is hard wired and independent of EPCU operation OFF - disconnects the main, auxiliary, and standby batteries from the associated essential buses NOTE: The battery master switch must be selected to BATTERY MASTER before the main, auxiliary, and standby batteries can power the respective buses. 5. GEN 1 and 2 SWITCHES (two position) GEN 1 OR 2 - DC GCU permits generator to supply power to the associated feeder bus - DC generators are inhibited with DC EXT PWR ON OFF - shuts associated generator off - resets GCU for subsequent generator and circuit monitoring following shutdown of a generator - DC GEN 1 or 2 caution light turns on anytime the respective generator is not supplying power to its associated feeder bus 6. MAIN BUS TIE SWITCH (two position, lever locked at OFF) MAIN BUS TIE - manually ties left and right main feeder buses. - EPCU inhibits bus tie operation upon detection of a bus fault OFF - manually opens connection between left and right main feeder buses 7. BUS FAULT RESET SWITCH (momentary selection) BUS FAULT RESET - re initializes the EPCU after a bus isolation (following a bus fault) to enable subsequent bus fault monitoring Page 7 Dash8 - Q400 - Electrical DC CONTROL OFF OFF AUX BATT STBY BATT GEN 1 MAIN BATT OFF OFF OFF OFF OFF BATTERY MASTER OFF OFF GEN 2 MAIN BUS BUS FAULT EXT PWR RESET TIE 8 Figure 12.5-4 DC Control Panel (3 of 3) Page 8 Dash8 - Q400 - Electrical DC CONTROL PANEL CALLOUTS (cont’d) 8. DC EXT PWR SWITCH EXT PWR - left and right main feeder buses, essential buses and secondary buses powered from DC external power source - DC and APU generators are inhibited from connection to feeder buses - DC EXT PWR ON vindication (green) is displayed on the MFD Electrical page when DC external power is connected to the aeroplane - the EPCU incorporates External DC Power Protection from too high or too low supply of External DC power voltage - external DC power is supplied to the aeroplane via the external DC power receptacle. The EPCU will enable the connection of the external DC power to the aeroplane if the applied external voltage is: • of correct polarity, and • its value is within 22 ± 1VDC to 31 + 0.5; 31- 0.75 VDC - main, auxiliary, and standby batteries are connected to their feeder buses - for the duration of engine start, the standby battery is inhibited from the left main feeder bus Page 9 Dash8 - Q400 - Electrical AC CONTROL + OFF OFF EXT PWR OFF GEN 1 1 GEN 2 2 Figure 12.5-5 AC Control Panel Page 10 Dash8 - Q400 - Electrical AC CONTROL PANEL 1. EXTERNAL POWER SWITCH (two position) EXT PWR - connects AC external power to variable frequency buses - is capable of powering all AC and DC buses on the aeroplane - isolates the AC generators from the buses - AC EXT PWR ON indication (green) is displayed on the MFD Electrical page when AC external power is connected to the aeroplane - an External Power Protection Unit (AC PPU) is installed in the right ACCB to ensure only AC Power within specification is allowed on the bus - the AC PPU checks for the following parameters: • voltage level (under voltage trip point 106 VAC ±2%, over voltage trip point 124 VAC ±2%) • frequency (underfrequency trip point 370Hz ±2%, overfrequency trip point 450Hz ±2%) • phase rotation (A-B-C) OFF - disconnects AC external power from variable frequency buses 2. AC GEN 1 AND 2 SWITCHES (two position) GEN 1 OR GEN 2 - arms respective GCU to activate, and connect its generator to the associated variable frequency bus - AC generators are inhibited with AC EXT PWR ON OFF - shuts respective generator down - resets GCU for subsequent generator and circuit monitoring following shutdown of a generator - AC GEN 1 or 2 caution light turns on anytime the respective generator is not supplying power Page 11 Dash8 - Q400 - Electrical 1 2 ELECTRICAL DC EXT PWR ON 3 APU GEN BATT LOAD MAIN AUX STBY °C +1. 00 +22 - . 34 +22 - . 34 +22 DC BUS 5 L ESS MAIN SEC FLAP DEG VOLT 27.7 28.5 26.1 0 5 10 AC GEN 1 LOAD +1. 00 DC GEN 1 4 AC EXT PWR ON . 06 TRU 1 A 115 B 115 C 115 . 06 . 06 . 06 AC GEN 2 R 27.7 28.5 26.1 LOAD 2 LOAD +1. 00 VOLT LOAD 2 +1. 00 +1. 00 VOLT LOAD A 115 B 115 C 115 . 06 . 06 . 06 HYD PRESS PSI x 1000 PK BRK STBY 1 2 35 HYD QTY % x 100 3 4 1 2 3 1 2 0 Figure 12.5-6 Copilot’s MFD Electrical Page (1 of 3) Page 12 0 Dash8 - Q400 - Electrical MULTI FUNCTION DISPLAY (MFD) ELECTRICAL PAGE CALLOUTS 1. DC EXT POWER ANNUNCIATOR (green) - displayed when a DC external power source is connected to the aeroplane and supplying DC power within voltage tolerances 2. BATTERY LOAD AND TEMPERATURE ANNUNCIATION AREA BATT (white) LOAD, °C (cyan) MAIN, AUX, STBY (white) 3. DIGITAL DISPLAY OF BATTERY LOAD (white) - displays the load of the battery - + or - sign on the left of the lead digit, whether the battery is in overcharge (“+” displayed) or in discharge (“-” displayed) - nothing is displayed when the battery is in charge within the expected range - leading zero is suppressed in the lead digit position - digital number gives the rate of the load, with 1.00 equal to 100% of load - examples: • “+1.30” indicates that the battery is in overcharge at 30% over the maximum rate of the charge • “.60” indicates that the battery is in charge at 60% of its maximum rate of charge • “-0.30 “indicates that the battery is discharging at 30% over the maximum rate of discharge 4. DIGITAL DISPLAY OF BATTERY TEMPERATURE - battery temperature digits are displayed in white with a + or - sign on the left of the lead digit, when the temperature is within normal limits - when the temperature is in the range (+50°C to +65°C) the digits turn yellow - when the temperature exceeds 65°C the digits are displayed in red 5. DC BUS VOLTAGE ANNUNCIATION AREA DC BUS (white) L, R (white) VOLT (cyan) ESS, MAIN, SEC (white) Page 13 Dash8 - Q400 - Electrical 7 DC EXT PWR ON MAIN AUX STBY °C +1. 00 +22 - . 34 +22 - . 34 +22 +1. 00 DC GEN ESS MAIN SEC VOLT 27.7 28.5 26.1 LOAD +1. 00 DC BUS AC GEN 1 LOAD 1 L AC EXT PWR ON APU GEN BATT LOAD 8 ELECTRICAL VOLT LOAD A 115 B 115 C 115 . 06 . 06 . 06 . 06 AC GEN 2 TRU 1 LOAD 2 +1. 00 +1. 00 VOLT LOAD A 115 B 115 C 115 . 06 . 06 . 06 6 PFCS SPOILERS LO RUD L1 R1 L R ELEV ELEV Figure 12.5-7 Pilot’s MFD Electrical Page (2 of 3) Page 14 11 9 2 R 27.7 28.5 26.1 9 10 10 Dash8 - Q400 - Electrical MULTI FUNCTION DISPLAY (MFD) ELECTRICAL PAGE CALLOUTS (cont’d) 6. DIGITAL DISPLAY OF DC BUS VOLTAGE (white) - indicates the voltage on the associated bus 7. DIGITAL DISPLAY OF APU GENERATOR LOAD (white) APU GEN (white) LOAD (cyan) - is activated only if the APU is installed depending on the aeroplane configuration - the load demand on the APU generator is displayed in the following format: • “+” sign is displayed on the left of the lead digit to indicate an overload of the DC power source • nothing is displayed when the load is in the expected range • leading zero is suppressed in the lead digit position • digital number gives the rate of the load, with 1.00 equal to 100% of load examples: • “.60” indicates that the DC generator or TRU is loaded at 60% of the maximum output • “+1.30” indicates an overload of the DC generator or TRU 8. AC EXTERNAL POWER ANNUNCIATION (green) - displayed when an AC external power source is connected to the aeroplane and supplying AC power 9. AC GEN VOLTAGE AND LOAD ANNUNCIATION AREAS AC GEN 1 and AC GEN 2 (white) VOLT, LOAD (cyan) A, B, C (white) 10. DIGITAL DISPLAY OF AC VOLTAGE (white) - displays AC bus voltage for each phase Page 15 Dash8 - Q400 - Electrical ELECTRICAL DC EXT PWR ON APU GEN BATT °C LOAD MAIN AUX STBY +1. 00 +22 - . 34 +22 - . 34 +22 +1. 00 DC GEN ESS MAIN SEC VOLT 27.7 28.5 26.1 VOLT LOAD A 115 B 115 C 115 . 06 . 06 . 06 11 AC GEN 2 12 2 LOAD . 06 +1. 00 DC BUS AC GEN 1 LOAD 1 L AC EXT PWR ON R 27.7 28.5 26.1 TRU 1 2 LOAD +1. 00 +1. 00 VOLT LOAD A 115 B 115 C 115 . 06 . 06 . 06 11 13 SPOILERS 0 5 10 FLAP DEG LO RUD LI RI L 35 R ELEV HYD PRESS PSI PK BRK 3000 STBY 0 1 2 3000 3000 ELEV HYD QTY % 3 Figure 12.5-8 Composite MFD Electrical Page (3 of 3) Page 16 RO 1 0 100 2 3 100 100 Dash8 - Q400 - Electrical MULTI FUNCTION DISPLAY (MFD) ELECTRICAL PAGE CALLOUTS (cont’d) 11. DIGITAL DISPLAY OF AC GENERATOR LOAD (white) - the load demand on the AC generator is displayed in the following format: • “+” sign is displayed on the left of the lead digit to indicate an overload of the AC power source • nothing is displayed when the load is in the expected range • leading zero is suppressed in the lead digit position • digital number gives the rate of the load, with 1.00 equal to 100% of load - examples: • “.60” indicates that the AC generator is loaded at 60% of the maximum output • “+1.30” indicates an overload of the AC generator 12. DIGITAL DISPLAY OF DC GENERATOR LOAD (white) DC GEN (white) 1,2 (white) LOAD (cyan) - DC generator load is displayed in the same manner as the APU generator load 13. DIGITAL DISPLAY OF TRU LOAD (white) TRU (white) 1,2 (white) LOAD (cyan) - TRU load is displayed in the same manner as the APU generator load Page 17 Figure 12.5-9 Pilot’s Lower Circuit Breaker Panel Page 18 1 2 3 4 5 6 7 8 9 10 75 A 10 TAXI PWR 5 B 5 C 5 EXT LIGHTS TAXI LDG CONT CONT 1 D 25 L FLARE 5 E 5 AIR STAIR 5 3 2 2 2 J ARCDU 1 3 H VHF NAV 1 2 G 10 F PLT AUDIO 5 VHF COM 1 3 STBY ATT 7 1 5 ENG 2 FADEC A 5 FUEL HLCU 3 CABIN PRESS MAN 5 FLAPS CONT 5 K 5 L 5 WRB & BAGGAGE FLT ATT ADV SIGNS LT 5 STORM/PLT CARGO CB PNL IND LTS 5 ENG 1 FADEC A 7 12 7 12 5 PROP 2 PEC B 5 ENG 2 IGN A 1 STBY ALT 5 EMER LTS 10 ENG 1 IGN A 5 PROP 1 PEC A 5 5 ENG 1 OIL CLG 75 STBY BATT M 5 FCS ECU 1 5 REFUEL DEFUEL 1 DE-ICE CONT 20 FAN 1 PWR SEC 2 FLAPS POS IND L 5 DC GEN 1 AUX BATT BUS FAULT RESET SW EXCITE CONT 50 FIRE DET ENG 1 VLV IND IND 5 RIGHT BUS TIE 50 1 STBY CMPS 7 1 ADVSY LTS PASS WARN SIGNS 3 FEEL ACT 1 3 3 3 ECIU A 5 ENG START 5 50 AUX BATT INPUT 1 INPUT 2 50 L MAIN INPUT 1 INPUT 2 L ESSENTIAL HYD SYS CONT 5 PITCH TRM ACT 1 PROP 1 BETA LTS SOL 7 12 3 PLT FLT 5 LDG GEAR ALT WOW 2 + CONT DLK IND 5 3 PANEL LIGHTS GLARE O/H CONS SHIELD 5 7 12 EMERGENCY LIGHTS PLT RELAY MAP LTS 3 5 RUD TRIM ACT IND 5 20 AIL TRIM ACT IND 20 50 BUS TIE AVIONIC FEEDERS HYD PRESS IND 1 TRIM IND ENG MONITOR 3 20 CABIN PRESS AUTO CONT 20 20 2 LDG GEAR ALT WOW 2 + CONT DLK IND 5 RUD SYS ISOL 50 L ESS BUS 2 5 50 3 FAN 3 PWR SEC FAN 1 PWR PRI 5 NLG STEER CONT 1 AC GEN CONT 1 5 VOLT IND 75 DC PWR MON L ESS BUS 1 3 5 5 20 75 ECS/BA CONT L AUTO R MAN 20 1 DE-ICE CONT 20 AVIONIC FEEDERS 75 L MAIN INPUT L MAIN 3 20 5 Q 5 P 25 N ATT RDG LTS 5 CABIN SIDEWALL LTS PWR 1 CONT 3 PROP 2 ALT FEATH 5 INTK DEF ACT 1 3 DR SEAL CV HTR RESTRICT 3 AIRFRAME DEICE V/HTR V/HTR #1 & #2 #5 50 L SEC INPUT 50 EXT LTS APPR L WING L PWR INSP 5 FLT COMP DOME LTS 5 PRESS IND 1 5 VOLT IND 50 10 MAINT PNL 10 PLT W/S WIPER 3 R 7 12 LAVATORY LTS 5 S 50 STBY HYD PRESS PROP 2 IND 1 AUX PMP 1 PLT WS/HT CONT 5 CV/DRAIN HTRS 3 PROP O/SPD DEICE CONT TEST 50 L SECONDARY Dash8 - Q400 - Electrical Figure 12.5-10 Pilot’s Upper Circuit Breaker Panel Page 19 1 2 3 4 5 6 7 8 9 10 11 LEFT MAIN RIGHT MAIN LEFT ESS TCAS 5 GPWS ANN 1 B 10 GPWS 3 A C 5 5 ESID CP PFD 1 EFIS CP 5 AHRS 2 CP AHRS 2 2 OBS AUDIO 5 D VHF COM 3 VHF 3 CP 2 VHF NAV 2 EFIS CP 2 7 1 VHF COM 2 5 VHF COM STBY 2 ARCDU 2 5 ICP 2 5 ICP 1 5 5 5 AHRS 1 CP AHRS 1 5 10 ESID PFD 2 10 10 MFD 2 10 MFD 1 2 ADU 2 2 ADU 1 7 12 PA AMP 5 PLT SPKR AHRS 1 CP AHRS 1 5 2 COPLT AUDIO 5 COPLT SPKR 5 AHRS 2 CP 10 ESID 5 2 RIGHT ESS AHRS 3 STBY ATT 10 E 7 12 F 5 7 12 AP AU PITCH SPM 1 1 7 12 AP AU ROLL FDR 5 CVR 5 SPM 2 10 YD AU 1 2 FLT ATTD ANN G 2 DME 1 2 DME 2 5 FG CP 2 5 10M/ 10P FG CP FGM 1 1 1/2 ELT CLOCK 10M/ 10P 2 FGM 2 1 AP DISENG ANN 1 1 CLOCK 1 1 AP DISENG ANN 2 H 1 WX CP 5 WX RDR 3 ADF 1 3 ADF 2 J 5 FMS 1 FMS 2 K 7 12 STICK PUSHER SELCAL MLS 1 MLS 2 HF COM 2 7 12 STICK PUSHER L 3 RAD ALT 1 RAD ALT 2 HF 2 AMP M HF COM 1 5 ATC 1 5 ATC 2 N HF1 AMP 1 ATC ANT SW P Q 2 FLT ATTD HANDSET PWR Dash8 - Q400 - Electrical Page 20 Figure 12.5-11 Copilot’s Lower Circuit Breaker Panel 1 2 3 4 5 6 7 8 9 10 CTRL 5 D 25 C 15 B 20 A EXT LTS R R WING FLARE INSP PWR 3 GALLEY PWR NVS 3 CABIN SIDEWALL LTS PWR 2 PWR 2 5 50 PWR 1 1 STBY HYD PMP 1 PROP 1 AUX PMP 3 FUEL XFER PANEL 1 PROP 1 ALT FEATH 5 5 10 CLOCK 2 1 CLOCK 1 1 2 5 5 5 7 12 K 5 J 5 H G F FLT COMP APU/CARGO DOME LTS MAN EXT 7 12 5 5 5 COPLT CB PNL LTS L 5 GEN EXC 50 R ESS BUS 2 50 R ESS BUS 1 5 1 M 7 12 PA EMER PWR 7 12 POSN 10 BATT REFUEL 7 12 2 3 5 N 25 P 5 EXT LTS APPR LDG R PWR CONT 2 3 COPLT CGO VENT VLS MAP LTS 7 1 CAUT/WRN CAUT/WRN LTS 1 LTS 2 5 5 NLG STEER CONT 2 5 AC GEN CONT 2 CONT 5 VOLT IND 75 PLT WDO HT RLY LDG GEAR WOW 1 WOW 1 + IND + IND SMK DET LAV/CGO1 BAG/CGO2 5 FCS ECU 2 5 25 5 PRESS IND 2 HYD SYS 3 CONT HYD BATT 75 STBY PITOT HTR STBY 5 PWR XFER 20 FUEL SOV ENG 1 ENG 2 5 7 12 BOARD'G LTS 7 12 2 ENG 2 FADEC B 7 1 ENG 2 IGN B 5 PROP 2 PEC A 5 AIRFRAME MANUAL CONT 5 BATTERY MASTER SW BATTERY PWR 5 ENG 1 FADEC B 7 1 ENG 1 IGN B 5 PROP 1 PEC B FUEL & FMU ENG 1 ENG 2 5 3 1 7 12 HYD SOV ENG 1 ENG 2 7 12 FIRE EXT/CONT AMP 1 & 2 ENG CARGO 3 7 12 3 ECIU B 5 PITCH TRM FEEL 2 ACT 2 ACT 2 3 5 REFUEL DEFUEL 3 PROP 2 BETA LTS SOL 5 IND 5 ENG 2 IND FIRE DET ENG 2 VLV IND 5 5 50 MN BATT INPUT 2 COOLING FAN 2 FAN CONT PWR SEC 50 MN BATT INPUT 1 BATT CONT STBY MAIN 5 LEFT BUS TIE 50 BUS TIE 10 DC GEN 2 EXCITE 5 SEC BUS TIE 5 DC PWR MON R ESSENTIAL ROLL SPLRS ARM OUTBD INBD INTAKE DEFLECT ACT 2 5 CABIN COPLT-WS PLT-MOD DUCT HT CONT TEMP IND 5 2 1 PRESS IND 2 COPLT W/S WIPER APU IND FLAP POSN IND R E 20 DC BUS TIE CONT ENG 2 MAIN OIL PRESS EXT PWR LOGIC 20 AVIONIC FEEDERS 50 5 3 V/HTR #6 5 ENG 2 OIL CLG 50 5 5 AIRFRAME DEICE CV DRN V/HTR HTRS #3 & #4 5 50 3 50 VOLT IND 50 PROP DEICE CONT 2 R MAIN INPUT 1 INPUT 2 3 5 AUTO DIST VLV 50 R SEC INPUT R SECONDARY 75 5 20 FAN 2 PWR PRI 3 20 FAN 3 PWR PRI 1 DE-ICE CONT 5 AFR DE-ICE BOOT LTS 20 75 Q 30 5 5 R 30 S 20 CABIN LTS PWR 2 20 CABIN LTS CONT PWR 1 5 READING LTS L R 7 12 ANTI COLL 5 PANEL LIGHTS COPLT ENG CTR FLT INSTR CONS 3 ANTISKID INBD OUTBD 5 ECS/BA CONT L MAN R AUTO PWR 20 AVIONIC FEEDERS APU FIRE 20 75 R MAIN INPUT R MAIN Dash8 - Q400 - Electrical PH A L ICE DET 1 5 PITOT HEAT 1 Figure 12.5-12 Copilot’s Upper Circuit Breaker Panel Page 21 5 35 L TRU FUEL AUX PMP 1 1 PH B PH C LEFT AC VM 10 INTK LIP HTR ENG 1 1 72 L AOA VANE HT L WSHLD HT 1 1 72 30 3 PH PH A L WDO HT R ICE DET 1 10 5 10 1 72 PITOT HEAT 2 FUEL AUX PMP 2 R TRU PH B 5 35 1 PH C RIGHT AC VM INTK LIP HTR ENG 2 R AOA VANE HT R WSHLD HT RIGHT BUS 115V AC VARIABLE FREQUENCY LEFT BUS 1 1 72 30 Dash8 - Q400 - Electrical Figure 12.5-13 DC Power Electrical Schematic - Fully Operational Page 22 #1 AC GEN OFF GCU L VARIABLE AC BUS L TRU #1 DC GEN OFF EXT PWR #1 AC GEN L SEC FEEDER L MAIN FEEDER AUX BATT AUX GCU BATTERY BUS #1 DC GEN GALLEY BUS STBY STBY BATT LEFT ESSENTIAL OFF EPCU MAIN BUS TIE OFF #2 AC GEN R SEC FEEDER R MAIN FEEDER GCU OFF ON GEN WARN OFF APU DC GEN GALLEY BUS GCU #2 DC GEN #2 AC GEN R VARIABLE AC BUS R TRU #2 DC GEN OFF GCU OFF BATTERY MASTER MAIN MAIN BATT RIGHT ESSENTIAL Dash8 - Q400 - Electrical STBY STBY BATT Page 23 #1 DC GEN L TRU #1 DC GEN OFF EXT PWR L SEC FEEDER L MAIN FEEDER AUX BATT AUX GCU BATTERY BUS LEFT ESSENTIAL OFF EPCU MAIN BUS TIE OFF R SEC FEEDER R MAIN FEEDER R TRU #2 DC GEN OFF GCU GCU #2 DC GEN OFF APU DC GEN ON GEN WARN OFF BATTERY MASTER MAIN MAIN BATT RIGHT ESSENTIAL Dash8 - Q400 - Electrical Dash8 - Q400 - Electrical 12.5.4 Detailed Description The Electrical Power Generation and Distribution System (EPGDS) (Figure 12.5-13) has an Electrical Power Control Unit (EPCU) to control, monitor and distribute DC power to the aeroplane’s electrical buses. The EPCU automatically re configures the EPGDS for power source and bus failures, by the closing and opening of bus ties contactors. Contactor control is determined by automatic functions during the operation of the aeroplane. Manual inputs are achieved through the selection of switches in the flight deck that may be vetoed by the EPCU. 12.5.5 AC/DC Power Monitor System System parameters are monitored in the flight deck on the Electronic System Indicating Displays (ESID). Select the SYS (System) position on the appropriate Multi Function Display (MFD) rotary switch on the ESID control panel to give electrical system indications. 12.5.6 DC System The DC electrical schematic is shown in Figure 12.5-14. The DC generation system has the following sources: • • • • • Main, Auxiliary, and Standby Batteries Two Starter/Generators Two Transformer Rectifiers Units (TRU) DC External APU Starter/Generator (Optional) The power sources supply power to the following buses in order of priority: • • • • Battery Left and Right Essential Left and Right Main Left and Right Secondary DC Electrical Medical Outlet A 24 VDC, 35 A electrical outlet for medical purposes is installed on the inboard face of the G1 galley. Page 24 Dash8 - Q400 - Electrical 12.5.6.1 Batteries The main and auxiliary 24-volt NiCad batteries are located in the lower left nose compartment. The main and auxiliary batteries have a 40-amp-hour capacity. The standard standby 17-amphour battery (optional 40-amp-hour) is located in the tail compartment, when no APU is installed. With an APU installed, the standby battery is located in the nose compartment. The MAIN and AUX batteries are used for engine starting if ground power is not available. All 3 batteries supply backup power to the aeroplane essential services in flight for 45 minutes or more. The batteries are connected to the left and right essential buses (Figure 12.5-15) by selecting the BATTERY MASTER switch. Selecting the BATTERY MASTER switch to the ON position closes 3 contactors and connects all three batteries to the essential buses. The connection required for the control of the above contactors is directly hard wired and is independent of the EPCU operation. The EPCU itself is energized from the essential buses. NOTE: Battery power cannot be applied to the secondary buses. Battery temperatures, as indicated on the ESID Electrical Page, should be equal to or greater than -20°C prior to dispatch. NOTE: There is no battery temperature limitation for starting Engines or APU. With the BATTERY MASTER switch on, the batteries are connected to the essential buses at all times. In this way powering of flight safety equipment, which is also connected to the essential buses, is enabled. In case of emergency operation the batteries are the main energy sources for the aeroplane. In addition to the BATTERY MASTER switch, each of the batteries has a dedicated switch. Selecting the MAIN BATT switch to ON, will directly connect the main battery to the right main bus. Similarly, selecting to ON of the AUX BATT switch will connect the auxiliary battery to the left main bus. The connections of the main and auxiliary batteries to the main buses are controlled by the EPCU logic. Conditions that require battery disconnection from the bus are the following: • • Emergency operation (defined later) Bus fault detected Manually selecting the STBY BATT switch to ON will connect the standby battery to the left main bus. This connection is achieved electronically by the EPCU if the following conditions are met: • • • DC external power (battery charge option) connected No emergency operation No bus faults detected MAIN BATTERY, AUX BATTERY and STBY BATTERY caution lights come on whenever the related battery is not connected to its feeder bus. A battery temperature indicator on the MFD Electrical page, continuously shows Main, Aux and Stby battery temperatures when selected on the ESID control panel. High battery temperature will turn on the MAIN BAT HOT, AUX BAT HOT or STBY BAT HOT warning light, and cause associated temperature value on the MFD to turn red. The warning light will go out when the temperature drops below the overheat condition. 17 AMP HR Standby Battery-Forward Fuselage The 17 AMP HR stanby Battery is re-located in the forward fuselage adjacent to the two 40 AMP Page 25 Dash8 - Q400 - Electrical The charge characteristics of the 40 Ahr batteries are as follows: Discharging Characteristics - The 40 Ahr batteries have a nominal voltage of 24 VDC (20 cells at 1.2 VDC/cell). This is the voltage that would be measured with a fully charged battery under a load equal to its ampere-hour rating, i.e. in this case 40 Ahr. The ‘no-load’ voltage as measured at the battery terminals approaches 28 VDC. This explains why the batteries will discharge with DC Ground power connected, particularly if the cart voltage is lower than 28 VDC. Battery reserves will be depleted at a higher rate, as the cart voltage is lower. Charging Characteristics - In order to restore batteries to a full state of charge, charging voltage should be at least 1.4 to 1.6 VDC/cell, or 28 to 32 VDC. This is provided with any DC generator on line. However, if an external ground power cart has an output voltage of less than 28 VDC, the batteries cannot be recharged to full capacity, regardless of the time that voltage is applied. When the DC External power cart output voltage is low, the discharge current from the batteries is not being supplied to the cart but instead supplied to the aircraft loads. When the batteries are online, the DC External cart and batteries are connected in parallel allowing current to be consumed by either source. If a low voltage output cart is connected with properly charged batteries online, as the case is after flight since the engine generators output 28.5 VDC to charge the batteries, the batteries will provide most of the current to the aircraft loads because charged batteries have a low internal impedance. As the batteries discharge, their internal impedance increases and most of the current to the aircraft loads is provided by the DC External cart. However by this time a significant portion of the batteries’ reserve can be consumed. Also, it should be noted that even if the DC External cart and the batteries are at the same potential, there would be a small current flow from the batteries. Based on the charge/discharge characteristics of NiCad batteries, it is evident that the external DC Power cart must have a voltage of at least 28 VDC or battery reserves will be depleted and cannot be fully restored. Operators are advised, that if 28 VDC carts are not available or their voltage is lower than 28 vdc, the batteries should be isolated from the aircraft loads by selecting the BATTERY MASTER, MAIN, AUX and STBY battery switches OFF while DC External power is connected. Page 26 Figure 12.5-15 DC Power System Battery Power Only Page 27 L TRU AUX BATTERY #1 DC GEN L TRU GCU AUX BATT OFF OFF EPCU L SEC DIST BUS L SEC FEEDER BUS L MAIN FEEDER BUS OFF R TRU R TRU R SEC #2 DC FEEDER BUS GEN R MAIN FEEDER BUS OFF #2 DC GEN #2 DC GEN OFF BEFORE START BATTERY MASTER SWITCH - ON MAIN BATTERY - ON AUX BATTERY - ON STBY BATTERY - ON GEN1 AND GEN2 SWITCHES - ON MAIN BUS TIE SWITCH - TIE NORMAL OPERATION: GCU OFF BATTERY MASTER MAIN BATT MAIN BATTERY MAIN BATTERY RIGHT ESSENTIAL R MAIN DIST BUS R SEC DIST BUS OFF MAIN BUS TIE L MAIN AUX BATTERY DIST BUS EXT BATTERY BUS PWR #1 DC GEN #1 DC GEN STBY BATT OFF STBY BATTERY STBY BATTERY LEFT ESSENTIAL Dash8 - Q400 - Electrical Dash8 - Q400 - Electrical 12.5.6.2 Starter/Generators The starter/generators are located on the accessory gearbox of each engine. Each starter/generator serves as a starter motor and will revert to generator operation if the DC GEN switch is in the ON position and the engine speed exceeds 50% NH following successful engine start. Each generator output is monitored and controlled by its Generator Control Unit (GCU). After engine start, the GCU ensures the generator supplies 28.5 VDC (400 Amps max) to its feeder bus regardless of load. The EPCU will then monitor and control the DC EPGDS. The EPCU will turn on the #1 DC GEN or #2 DC GEN caution lights in the event the DC generator is disconnected from its feeder bus. If a generator overheat condition occurs, the appropriate caution light #1 DC GEN HOT or #2 DC GEN HOT will come on. The light will go out when the temperature drops below the overheat condition. 12.5.6.3 Transformer Rectifier Units Located in the nose, the two Transformer Rectifier Units (TRU) change three-phase, 115-volt, variable-frequency AC input power into 28 VDC (300 Amps max) nominal output. The TRUs are unregulated but provide DC power in the range of 26 to 29 VDC during operation. Under normal conditions, each TRU powers its respective secondary bus. The L TRU or R TRU caution light comes on if either TRU is off line or failed. The L TRU HOT or R TRU HOT caution light comes on if the sensor in either detects an overheat condition. The light will go out when the temperature drops below the overheat condition. The two TRUs alone are capable of powering the entire DC system. 12.5.6.4 Auxiliary Power Unit (APU) Starter/Generator The APU Starter/generator is located in the tail cone section of the aeroplane. The APU is designed to supply 28VDC to the essential main, and secondary DC buses on the ground. A Contactor allows the connection of the APU Starter/generator to the right main feeder bus for APU starting and powering of the aeroplane DC buses. Its control is achieved from the APU GCU. After the APU is started, the starter/generator is available to supply power in parallel with the batteries to start the aeroplane engines. Page 28 Dash8 - Q400 - Electrical 12.5.6.5 Fault Tolerant Operation The DC Power subsystem is extremely tolerant to power source failures. It has four separate sources of DC power in flight. They are the two generators and two TRUs. When all DC power sources are operational, each source powers its own dedicated bus. When one or more source failures are detected, the EPCU will automatically reconfigure the power flow. The EPCU monitors the system for failures. Once a failure is detected, the EPCU will cause the bus system to reconfigure and ensure mission completion with minimal effect for the EPGDS and for the utilization equipment power supply. Four bus tie contactors are controlled by the EPCU that connect the appropriate feeder buses together when there are one or more inoperative DC power sources. The EPCU ensures operation of all DC buses with loss of up to two power sources. Automatic load shedding will occur only after more than two DC source failures. The four contactors connect the following feeder buses: • • • • L Main to R Main L Secondary to R Secondary L Main to L Secondary R Main to R Secondary For example, if one DC generator fails, the L to R Main bus tie closes and the other generator then powers both main feeder buses. If one TRU fails, the L to R secondary bus tie closes, and the other TRU then powers both secondary buses. If both DC generators fail, the vertical bus tie close, and the TRUs supply DC power to both the secondary and main buses. If both TRUs fail, the vertical bus tie close, and the DC generators supply power to both secondary buses. The EPCU operates in emergency mode when: • • • the aeroplane is in air and both DC Generators are not available and at least one TRU is not available When the EPCU operates in emergency mode, it automatically disconnects the batteries from the main buses. The main buses are not powered in this mode. In case of emergency operation the batteries are the main energy sources for the aeroplane. If an engine start attempt is made during an emergency condition, the batteries will automatically be reconnected to the main buses for the duration of the start attempt. 12.5.6.6 Bus Fault Protection The EPCU and the DC GCUs protection function protects the DC subsystem against short circuits on the main and secondary buses. The selectivity and protection coordination is ensured by the logic, detection and by reaction timing in these units. Page 29 Dash8 - Q400 - Electrical 12.5.6.7 Main Bus Failures If a main bus fault occurs, the EPCU prevents the upper horizontal and two vertical bus ties from closing, isolating the bus. The DC BUS caution light comes on to warn of the fault impending condition. If the fault persists after approximately 5 seconds, the EPCU sends a TRIP signal to the GCU, isolating the affected generator. The EPCU will also open and lock-out the contactors connecting the batteries to the affected main bus. The MAIN BATTERY or AUX and STBY BATTERY caution light(s) and related DC GEN caution light will come on as a result. The EPCU continues to monitor the operating buses. All main DC services on the faulted bus side will not function. NOTE: Manual operation of the main bus tie through the MAIN BUS TIE switch is not possible once the EPCU has reacted to a fault. If the fault subsequently clears, power may be restored with the BUS FAULT RESET switch. 12.5.6.8 Secondary Bus Failures In the case of a secondary bus short, the over current condition will immediately trip the associated TRU primary circuit breaker. Seven seconds later, with the EPCU declaring TRU failed the contactor L to R Secondary bus tie will close, transferring the short circuit to the opposite side TRU. At that moment, the cross tie fuse is blown isolating the fault. This is indicated by a L TRU or R TRU caution light and loss of services on the associated secondary bus. Page 30 Dash8 - Q400 - Electrical 12.5.6.9 Engine Starting The starting process is initiated by selecting an engine position using the SELECT switch from the Engine Start control panel. The starting process is initiated by depressing the START button. The power source (which feeds the main buses for the supply of the starter/generator) for the starting process can be different. Therefore, the availability of different power sources results in the following starting modes: • • • • Starting from batteries Generator assisted starting Starting from DC external power APU assisted starting In all cases the BATTERY MASTER, MAIN BATT, AUX BATT, STBY BATT and MAIN BUS TIE switches are selected on prior to start. a) Starting from Batteries Only the main and auxiliary batteries, in parallel, participate in the starting process. The standby battery is diode isolated from to the left main, to ensure an acceptable level of voltage on the essential buses during engine start. NOTE: Observe starter cranking limits. NOTE: After an aeroplane NiCad battery start, the charge rate for fully serviceable batteries will decrease after approximately three minutes. NOTE: Battery temperatures and charging rates must be continuously monitored on the MFD Electrical page, while charging. b) Generator Assisted Starting The generator assisted starting is usually performed, after the start up of an engine is finished (in any mode of starting). After the right DC generator is connected to the right main bus, together, in parallel with the batteries, will perform starting of the other engine. During the start process and 15 seconds following it, the DC GCUs will be supplied with a ‘CURRENT LIMIT’ signal. This will limit the current the opposite side generator will contribute to the starting and also to limit the current the starter/generator (in generating mode) will supply to the loads. Page 31 Dash8 - Q400 - Electrical A OPEN CLOSED A fs number Figure 12.5-16 DC External Power Receptacle Page 32 Dash8 - Q400 - Electrical c) Starting from DC External Power A Ground Power Unit (GPU) can be connected to the DC external power receptacle (Figure 12.5-16) on the left side of the forward fuselage. The GPU can supply DC power for the aeroplane EPGDS and for engine starting (Figure 12.5-17). Contractors connecting the main and aux batteries to the main buses are closed automatically upon selection of engine start, as the main and auxiliary batteries assist in the start. The standby battery is diode isolated from the left main, to ensure an acceptable level of voltage on the ESS Busses during the starting process. When the starting process is terminated the power source is still the external power. While DC external power is connected to the aeroplane, the generators connections to the main buses is inhibited by the EPCU. The main and auxiliary batteries stay connected to the main buses and the standby battery is reconnected. Once the DC EXT PWR switch is turned off after engine start, the generators will come on line if the GEN switches are in the ON position. Both vertical bus ties connecting the main to the secondary buses will remain closed until DC power is available from the TRUs. The EPCU incorporates external DC power protection from too high or too low supply of external DC power voltage. If the external voltage is more than 31+0.5/-0.75 VDC, or less than 22 ± 1 VDC, an over/under voltage condition will cause the external ground power to stop supplying electrical power to the aeroplane. If the external power over/under voltage is rectified, the external power source can be reselected by moving the DC EXT PWR switch to OFF and then to EXT PWR. Page 33 Figure 12.5-17 External DC Power Schematic Page 34 L TRU #1 DC GEN L TRU GCU AUX BATT OFF OFF EPCU L SEC DIST BUS L SEC FEEDER BUS OFF R TRU R SEC FEEDER BUS #2 DC GEN OFF OFF #2 DC GEN #2 DC GEN R TRU GCU OFF BATTERY MASTER MAIN BATT MAIN BATTERY RIGHT ESSENTIAL R MAIN FEEDER BUS R SEC DIST BUS OFF MAIN BUS TIE EXT PWR L MAIN FEEDER BUS L MAIN BATTERY AUX BUS BATTERY DIST BUS #1 DC GEN #1 DC GEN STBY BATT OFF STBY BATTERY LEFT ESSENTIAL Dash8 - Q400 - Electrical Dash8 - Q400 - Electrical 12.5.7 AC System The AC electrical schematic is shown in Figure 12.5-18. Electrical power sources for the AC portion of the EPGDS include: • • Two alternating current variable frequency generators AC External The power sources supply power to the following buses in order of priority: • • Left or Right AC bus Left or Right Galley bus During normal mode of operation, one AC source supplies its dedicated bus. AC power is required for the following systems: • • • • • De-icing/Anti-icing heaters Standby hydraulic pump Galley loads Transformer Rectifier Units (supplements DC power) Auxiliary fuel pumps AC Electrical Outlet A 115 V AC, 15A, 400 Hz electrical outlet for vacuum cleaning requirements is installed on the inboard face of the G1 galley. 12.5.7.1 Variable-Frequency AC Power Two 115 V, 45 KVA AC generators (mounted on the propeller reduction gearbox) supply variable frequency (340 to 560 Hz) AC power. The AC power is supplied to the left and right AC buses. AC power sources are prevented from being operated in parallel. AC power is available once the condition levers are out of START & FEATHER in the MIN/850 to MAX/1020 range, and the GEN 1 and GEN 2 switches on the AC CONTROL panel are on. If one AC generator fails, the #1 AC GEN or #2 AC GEN caution light comes and the remaining generator is capable of carrying the aeroplane’s AC electrical load except galley power. An automatic cross tie function, controlled by the AC GCU logic circuits, ensures that all variable-frequency buses are powered when only one AC generator is on line. Whenever a fault condition exists, the GCU of the inoperative generator issues a transfer request signal to the operational side AC GCU. The operational side AC GCU will issue a CLOSE command to the failed side line contactor. In this configuration, the remaining generator will power both AC buses. In this situation the load shedding relays will not allow power to the galley buses. The AC generators are protected from bus faults by the GCUs that detect any excessive load that might result from a short circuit on a bus. Once a heavy load is detected, the GCU isolates the bus, and turns on the appropriate L AC BUS or R AC BUS caution lights. The # 1 AC GEN HOT or # 2 AC GEN HOT caution lights come on whenever an AC generator overheats. The AC generator must be switched off. NOTE: All AC and DC aeroplane services can be operated from the AC generators or the AC external power alone. Page 35 GALLEY BUS Page 36 GCU #1 AC GEN HOT #1 AC GEN OFF L VARIABLE AC BUS L TRU #1 AC GEN #1 AC GEN L AC BUS 28V DC #2 AC GEN R AC BUS EXT PWR #2 AC GEN OFF 28V DC #2 AC GEN HOT GCU #2 AC GEN R VARIABLE AC BUS R TRU OFF GALLEY BUS NOTE Condition levers above start and feather. Min/850 to Max/1050 RPM range. AC GEN1 and AC GEN2 switches on. Dash8 - Q400 - Electrical Dash8 - Q400 - Electrical A GROUND POWER A.C. 115V Figure 12.5-19 AC External Power Receptable Page 37 Dash8 - Q400 - Electrical 12.5.7.2 AC External Power Location of the AC Ground Power Connection A GPU can be connected to the AC external power receptacle on the forward right hand fuselage near the nose cone (Figure 12.5-19), to supply AC power to the aeroplane. An external power switch on the overhead AC CONTROL panel (Figure 12.5-5) connects power directly to the left and right variable-frequency buses, supplying power to all AC and DC buses. The External Power Protection Unit monitors the qualities of the incoming power. The external power must be within acceptable limits, otherwise the external power is rejected. 12.5.7.3 External Power Protection An External Power Protection Unit (AC PPU) is installed on the right ACCB to make sure the external ground power is within specified limits before supplying power to the aeroplane busses. The AC PPU monitors the following parameters: • • • • • Undervoltage Overvoltage Underfrequency Overfrequency Phase Rotation (A-B-C) 12.5.8 Circuit Breakers The EPGDS utilizes passive protections in the form of circuit breakers and current limiters. Circuit breakers are protection devices that open the circuit in case of excess current flow. Circuit breakers protect electrical system power sources, component control circuits and bus distribution. There are circuit breakers on: • • • Four flight deck circuit breaker panels DC Contactor box in the nose compartment AC contactor boxes in the left and right main landing gear wheel wells Two wardrobe circuit breaker panels Each circuit breaker is identified by the: • • • • Circuit breaker panel Electrical bus Identification label Alphanumeric location. Page 38