RI-15 (I4390): 8/2/05

•	Electrical System
* 5 Amp fuses/CB for everything on fuel bus but fuel bus boost pump (10)
* AC ground: 1000A for 0.1 sec, 300A continuous
* Inverter circuits: each 26V:5A fuse, each 115V:6A fuse, 1A fuse for everything on bus.
* Lose inverter select relay fuse, lose that side's 115VAC bus.
Malfunction: Gen Fail...
Evaluate Current Limiters, 3 possibility:
1) Good Current Limiters: no drop in batt, everything works.  Keep load under 1.0.
2) Bad CL (same side): lose avionics bus, fuel bus, inverter for that side.
3) Bad CL (opp side): batter discharging, everything works.  Conserve batt.
1) Gen - OFF, Reset, back on
2) Gen - OfF (if still broke)
If works in reset, Gen Control Box broke.
3) CLs check
4) Op gen - don’t exceed 1.0
5) Land as soon as practibile 
NOTE: Fail w/ smoke+fumes=internal failure.  Check by closing bleed air.  Consider engine shutdown.

Dual-gen Fail:
Ensure maximum battery duration
1) Cabin Temp, heater, antiice/deice, autoignition, lights, radar - OFF
2) Emergency voice report - complete
3) VMC - Gang Bar - OFF, IMC - Gens -OFF
4) Boost pumps - OFF
5) VMC - Inverters - OFF, IMC  - #2 Inv:OFF
6) Pull a lot of CBs.
7) VMC: Avionics Master - OFF, Batt - ON
8) IMC w/ GCA: Pull a lof of Nav CBs
9) IMC w/VORTAC: Pull more CBs for other stuff.
Note: No-flap, pump down the gear.

Excessive Load:
Due to ground fault or excessive batt charge.
1) Battery/Ammeter - Check
>30 A: 2) Battery - OFF
3) Battery/ammeter - Check
>30 still: battery relay failed.  Land as soon as possible.  If it drops:
4) Recheck loadmeters
If normal, excessive battery charge.  Land as soon as practibile.  If excessive, ground fault land as soon as possible.  Watch for fire.  Note: load splits >0.1=bad paralleling.  W/ AC on, CL broke.

Inverter Fail
1) Failed Inv - OFF
2) Check for AC Switchover.
3) Land as soon as practibile.

Inst Inv Fail
Torquemeters Lie.  Can’t fix.

Tripped CB:
1. Nonessential - Don’t reset.
2. Essential- Push to reset.  If pops again, do not reset.
DON’T Reset Subpanel Feeder CBs.

Avionics Master
Lose all avionics, poweris good.  Pull MASTER POWER CB.

1)  Battery:  24v 42a  lead acid, in right wing root.   Emergency power, starts engines, acts as damper.  

2)  Starter/Generator:  250 amps (Accessory gearbox) Generator Control Box located under main wing spar in center aisle.  (Regulates voltage, automatic paralleling, overvoltage protection 31VDC, undervoltage protection 18VDC, reverse current protection)  Load is measured in percent of 250 amps.  (.3-.6)

3) APU in rt engine nacelle...  No more than 28VDC, capable of 300A with 0.1 sec bursts of 1000A. 

4) DC Busses:  10:  Hot Batt Bus, Batt Bus, #1/2 Subpanel Bus, #1/2 Avionics Bus, L/R Main Bus, #1/2 fuel bus.  Hot batt bus:  Singularly powered:  L/R Fire Extinguishers, Threshold lights (wing spar, baggage door, cabin door observer lt, aft compartment lt, xfeed lt) Dual powered (w/fuel bus): L/R Boost Pumps, L/R Firewall Valves, Xfeed valve.

5) Current limiters: Bus ties.  Allow either bus to get power from other generator..   Also isolates shorts from rest of system.  325A Slow fuse.   

6)  Inverters:  750 Volt-Ampere single phase inverters.  Supplies 26Volt AC,for Torquemeters, 115 vac for the avionics.  Inverter relays driven off inverters, fail-safe?  System adjusts for failed inverters.  If you lose an inverter relay select fuls, you lose the AC avionics on that side.  

7)  Lights:  Master Cockpit is everythign except for Threshold lights, Door locking light, Seatbelt light, reading light, utility light, indirect instrument lights, aft compartment ligght.  Pull GYRO INST CB if Master Cockpit lights fails, for all lights other than gyro lights.  Exterior lights (Landing/Taxi) shutoff with gear retraction.

8) Emergencies:  Generator fail boldface:  good voltage in RESET indicates failed gen control, not bad generator.  Lose both gens, on battery power (42Ah remains.) Run off math from batt amp. Current limiter fail inflight = 0.2 difference btw busses.  Ususally L. Main higher.  Both curr limiter fail, same thing as one failing.  Variable split in loadmeters.  Gen fail w/opp Curr Lim fail:  everything works, but batt being discharged.   Same side gen fail curr lim fail, lose avionics bus, lose fuel bus on that side.  Inverter fails, turn it off and land.  Total AC failure: can only uses fuel flow, oil px, itt, n1, pitot static, prop rpm, clocks, ncs31, aoa, radalt, compass, turn and bank.  (Heading, attitude, nav all fail, and torque.)  Only have DME, ADF audio, XPDR, marker beacons, UHF VHF audio.  

9) CBs:  Can reset once, but NOT Subpanel feeder, non-essential.  If Avioinics Master switch fails, pull Master Power CB to bypass.    

1. Sources of DC power: 1 24V/42A battery, 2 28V/250A starter-generators
2. Sources of AC power: DC power routed through 2 750V-A single-phase inverters.
3. The generator control box: overvoltage protection (31V), undervoltage protection (18V), reverse current protection, & automatic paralleling.
4. The generator control boxes are under the cabin center aisle aft of the main spar.
5. The inverters are located outboard of the engines on the wings.
6. The current limiters: tie the main buses & provide fault protection.
7. To get around a faulty master avionics switch, pull the master power CB.
8. Limitations of the generators: 28.25 (+/- 0.8)V.
9. Limitations of the inverters: 114 (+/-7)V, 400 (+/-6)Hz.
10. For APU start, the unit must be able to provide 1000 Amps for 0.1sec and 300Amp continuous load thereafter.
11. A failed Inverter Select Relay Fuse will cause failure of respective AC bus without illum of inverter light (switch over impossible).
12. Illum of INST INV OUT light indicates loss of 26VAC inverter select relay & torquemeters.
13. Procedures for INVERTER failure: [1] Fail Inverter - OFF [2] AC Bus switchover [3] Land ASA practicable
      Total ac failure, still have: fuel flow, oil press, oil temp, turn & bank, pitot static, N1, ITT, prop RPM, clocks, NCS-31A, AOA indexers, RADALT, wet compass14. Procedures for GENERATOR failure: OFF, reset momentarily, ON.
15. If generator fails to reset, yet registers normal volts in reset position, indicates failure of generator control.
16. Total loss of power, still have: copilot turn and slip, VSI, altimeters, airspeed indicators, wet compass, N1 and N2, ITT, & clocks.
17.  Dual inverter failure, still have DME, radar, VOR (audio), ADF-LF (audio), xponder, MKR BCNs.  For comm still have, UHF & VHF.
18. Excessive load indications (>1.0): [1] Battery/ammeter - Note.  If charge rate in excess of 30A: [2] Battery - OFF. If loadmeter still over 1.0: [3] Non-essential loads - OFF.  Splits of >0.1 indicate abnormal generator paralleling.
19. If get a GEN OUT light, check Current Limiters: [1] Battery- no discharge, no other equip failures = CL intact. [2] Battery - discharge, no other equip failures = opposite CL failed. [3] Battery - no discharge, other equip failures = same side CL failed.