24 Electrical Power Flashcards
Describe the B300 electrical system.
28 Volt DC, single loop, triple fed bus with a negative ground.
What components provide your electrical needs?
2 - 28v 300amp Starter gens, 24 volt nicad or 24 volt lead acid.
What are the 5 primary buses?
hot battery bus, center bus, triple-fed bus, left and right generator buses.
Termed a triple fed bus because?
Being fed by 3 primary power sources.
Describe the AC electrical system.
115 VAC & 26 VAC, single phase, 400Hz system, consisting of 2 static inverters, 2 bus transfer relays, ac power monitor circuit, CB’s and annunciators.
During simultaneous operation what happens to the inverters?
They are synchronised.
Power sources for the inverters?
1 - center bus, 2 right gen bus
The bus transfer relays located in the fuel control panel provide what purpose for the AC system?
Manually transfer AC equipment draw from one inverter to the other.
What is the function of the AC power monitor PCB
Monitors both 115/26 VAC buses, both switches and provides power to your #1/2 AC BUS anunciators, closes the sync line
Voltage and frequency regulation?
Voltage - +5% to -7%, freq 400 +/-1%
If a inverter switch is placed to the TRANSFER mode all its load is directed where?
It is shut down and load is transferred to the opposite inverter?
What is the optional AC elec system?
230 VAC 50Hz
What is the purpose of the AC Power Controller?
Distribute to AC power outlets, a RED diag led on the controller indicates a fault.
The DC generation and control system consists of?
2 dual purpose 28 volt, 300 ampere starter gen units for starting and electrical generation.
What would happen if excessive torque is applied at the starter gen spline?
it would shear.
Explain the winding used of the generators.
Series starter winding is used for starting, shunt field winding is used for generation.
Where is the GENERATOR CONTROL PANEL located and what is its purpose?
Main power distribution panel, line contactor relay control, voltage regulation, generator parralelling , differential voltage sensing, reverse current sensing , overvoltage, over excitation, cross starting
Line contactor relay of starter gen system?
each starter gen is connected to its bus by a line contactor relay. the generator control panel will cut power at this relay when a fault is evident.
Starter Gen paralleling
Maintains startgens electrical loads within 10% of each other, by measuring interpole winding voltages
Overexcitation protection
The affected starter gen will be de-energized if generator bus voltage exceeds 28.25 VDC and output differential is greater than 15% for 5 seconds.
Overexcitation protection
The affected starter gen will be de-energized if generator bus voltage exceeds 28.25 VDC and output differential is greater than 15% for 5 seconds.
Reverse current and polarity protection.
If a starter generator is under performing or becoming a load of the system the GCP will open the line contactor relay and remove the affected starter gen from the circuit.
Over voltage protection
If a starter gen exceeds 32.5 VDC, an inverse time delay will trip an internal field de-energizing the affected starter gen. Requiring a manual reset.
What happens if voltage exceeds 40 VDC from a starter generator?
A completly seperate circuit will open the line contactor relay to immediately disconnect the starter gen.
