Ignition Systems
In a high tension turbine engine ignition system, what input voltage is applied to the system
115 volts 400 hertz alternating current
Which federal aviation regulation states that each spark ignition engine must have a dual ignition system with at least separate electrical circuit with separate sources of electrical energy or have an ignition system with equivalent in flight reliability?
14 CFR 33
What is the input voltage of a low tension gas turbine engine ignition system
28 volts DC
Once the center or ground electrodes are worn, how much percent the spark plugs should be replaced
50%
How does the ignition system of a gas turbine engine differ from that of a reciprocating engine?
A high-energy spark is required for ignition.
Cleaning magneto components must be done with only what?
Approved solvent and cleaning methods
When a shower of sparks ignition system starts both the retard and advanced points
Both must be open
What mechanical devices consist of two
Breaker points
What phenomenon appears as a fine pencil like
Carbon tracking
When the ignition switch is in the OFF position, what is the condition of the primary circuit?
Closed, grounded
The rotational speed necessary for a magneto to fire a spark plug is known as magneto what
Coming in speed
What type of turbine engine igniter plug has the center electrode recessed in the body of the plug?
Constrained gap igniter
In an aircraft ignition system, one of the functions of the capacitor or condenser is to what?
Facilities a more rapid collapse of the magnetic field
What phenomenon causes the spark to jump to the wrong electrode in the distributor of a magneto
Flashover
How many positions are on a typical ignition switch?
Four
What type of igniter is a resistance coil that generates a very high heat value, capable igniting a fuel air mixture
Glow plugs
What are the basic components of a high tension magneto?
Harness and Spark Plugs
The capacitor type ignition system is used almost universally on turbine engines because of its what?
High heat intensity
What is the purpose of shielded ignition leads?
It prevents current leakage and reduces radio interference
Name the parts that are in the magnetic circuit
Magnet and Pole Shoes
Any complete path of magnetic lines of flux that leave the North Pole of the electrical machine such as a motor or generator and enters the magnetic South Pole is known as what?
Magnetic Circuit
Where is a compensated cam used?
On magnetos installed on radial engines
The distributor rotor in a magneto always turn how much in relation to the engine crankshaft
One half
At the E Gap position the breaker points are what?
Open
Once you have done maintenance on an ignition switch, what should be accomplished?
Operationally check the switch
What does a magneto in a high tension system utilize instead of a battery to induce voltage into an ignition system?
Rotating magnet
The circuit inside the magneto which produces the high voltage energy required to produce a spark
Secondary
If the ignition switch is in the OFF position, how is the mag affected
The P Leads on both magnetos are grounded
What is used to prevent arcing across the points when they open and increase the rate the magnetic field and the primary winding collapses?
The condenser or capacitor
Why are igniter plugs in gas turbine engines less to fowling
The high energy spark removes carbon and other deposits
If you have a single probe cylinder head temperature system,
The hottest cylinder
What device in a battery or magneto ignition system steps up the voltage to
The ignition coil
Describe the neutral position
The magnetic field is at its weakest point
When timing a magneto internally, the alignment of the timing marks indicates what?
The magnets are in the E gap position
What system of the magneto consists of the housing, driveshaft and othe non electric
The mechanical system
How are the spark plugs grounded?
Through the stricture of the magneto
What is the purpose of a resistor on a spark plug?
To prevent capacitance after firing
What is the primary function of a turbine engine ignition system
To provide the spark needed for combustion, ignited the fuel in the combustion chamber during engine start
What is E-gap angle?
When the magnetic field collapses and the breaker points open
The E gap angle is usually defined as the number of degrees between the neutral position of the rotating magnet and the position of what?
Where the breaker points open
