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Bell 407 > Electrical System > Flashcards

Electrical System Flashcards

1
Q

Voltage of the electrical system

A

28 VDC

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2
Q

General description of the electrical system

A

28 VDC electrical system
24v 28amp Lead Acid Battery
30v 200 amp Starter/Generator
- solid state voltage regulator

All circuits are single wire with fuselage common ground

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3
Q

What type of battery do we have?

A

24v 28 amp Sealed Lead Acid Battery

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4
Q

Where is the battery located?

A

aircraft nose compartment

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5
Q

Describe the battery relay

A

Connects battery to main bus bar

- located under shelf of battery compartment

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6
Q

Describe the battery switch

A

Opens/closes circuit to relay

- located on overhead console

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7
Q

Describe the external power system

A

28 VDC Ground Power Unit (GPU)

  • 500 amp limit to reduce risk of starter damage due to excessive heat
  • Through External Power Relay connected to buss
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8
Q

What does the starter/generator system consist of?

A 
30v 200amp Starter/Generator
Voltage regulator
Generator Relay
Reset switch
Shunt
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9
Q

Generator Limitations

A

0-200 amps
Continuous <10,000

200 amps
Max Continuous <10,000

180-300 amps
Transient: 2 min

300-400 amps
Transient: 5 sec

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10
Q

Starter Limitations

with Battery

A 
60 sec - ON
60 sec - OFF
60 sec - ON
60 sec - OFF
60 sec - ON
30 min - OFF
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11
Q

Starter Limitations

with External Power

A

28 VDC GPU Limit 500 amos

40 sec - ON
30 sec - OFF
40 sec - ON
30 sec - OFF
40 sec - ON
30 min - OFF
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12
Q

Voltage regulator with the Gen switch On

A

VR monitors and controls output voltage
- connects generator to 28 VDC bus through relay

Voltage Regulator disconnects Gen from system if:

  1. Under voltage 18 +/- 1.8v
  2. Over voltage 32 +/- .5 v
  3. Reverse current (0.8 - 0.15 VDC, for 350 milsec)
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13
Q

Describe the starter system

A

Includes - starter, relay, FADEC/starter relay, starter switch

Start switch engaged: Power supplied to starter through its relay
- relay located on electrical shelf above baggage

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14
Q

What is the purpose of the igniter exciter

A
  • Igniter exciter provides increased voltage to igniter plug to ensure fuel ignition during start cycle
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15
Q

Describe the ignitor system

A

With starter switch engaged

  • Igniter exciter provides increased voltage to igniter plug to ensure fuel ignition during start cycle
  • Power is supplied to igniter and VR through FADEC/Start Relay and igniter relay when starter is engaged
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16
Q

Start CAS

A

Starter relay is energized

  • AUTO Mode: start relay stays engaged until 50 +/- 1 Ng
  • MANUAL Mode: start relay stays engaged until start switch is released from start position
17
Q

Auto Relight CAS

A

Engine Igniter is operating

Activated when:

  • During start sequence up to 60% Ng
  • In Manual Mode > 55% Ng
  • If FADEC Detects engine out > 50% Ng
18
Q

GEN Fail

A

Gen will not come on until output is >/= 24v +/-2.4

Voltage Regulator disconnects Gen from system if:

  1. Under voltage 18 +/- 1.8v
  2. Over voltage 32 +/- .5 v
  3. Reverse current (0.8 - 0.15 VDC, for 350 milsec)

GEN Fail CAS - Gen not connected to DC Buss

  1. verify Gen Switch - ON, then RESET, then ON
  2. If CAS remains, Gen - OFF
  3. Land as soon as practical
19
Q

Under what conditions would the voltage regulator disconnect the generator from the system?

A

Voltage Regulator disconnects Gen from system if:

  1. Under voltage 18 +/- 1.8v
  2. Over voltage 32 +/- .5 v
  3. Reverse current (0.8 - 0.15 VDC, for 350 milsec)
20
Q

Gen Fail CAS

A

GEN Fail CAS - Gen not connected to DC Buss

  1. verify Gen Switch - ON, then RESET, then ON
  2. If CAS remains, Gen - OFF
  3. Land as soon as practical
21
Q

Battery life if total electrical failure

A

Battery switch immediately turned off

- with 80% charge: can supply fuel boost/xfr pumps approximately 2.8 hours

22
Q

What are the Fail Safe - ON items in the event of full electrical failure?

A
  1. Anti-Ice
  2. Hydraulic Solenoid
  3. Pedal Stop System - with Vne of 60 knots
  4. Left boost/transfer Pump Alternate Circuit
    - with battery/generator off, and fuel valve on
23
Q

What do these relays do:

  • Battery relay
  • Generator relay
  • Starter relay
A

Battery relay: connects battery current to main bus bar. The battery switch opens and closes the circuit to the relay
Generator relay: connects generator to main bus bar, controlled by the VR
Starter relay: energizes the starter to start when switch is engaged

24
Q

Describe the Battery Alternate Circuit

A 
Allows operation of the left fuel boost/transfer pumps
Battery - OFF
Circuit Breaker - IN
Fuel Valve - ON
Left B/T Switch - ON

Bell 407 (19 decks)

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