Ignition and Starting Systems Part 3 Flashcards
Magneto breaker points must be timed to open when the
greatest magnetic field stress exists in the magnetic circuit.
Which of the following would be cause for rejection of a spark plug?
Insulator tip cracked.
When testing a magneto distributor block for electrical leakage, which of the following pieces of test equipment should be used?
A high-tension harness tester.
Which of the following could cause damage to the nose ceramic or to the electrode of an aircraft spark plug?
Improper gapping procedure.
A safety feature usually employed in pneumatic starters that is used to prevent the starter from reaching burst speed if inlet air does not terminate on schedule is the
drive shaft shear point.
When using an electric starter motor, current usage
is highest at the start of motor rotation.
If an ignition switch is turned off and the engine continues to run normally, the trouble is probably caused by
an open ground lead in the magneto.
Magneto timing drift is caused by erosion of the breaker points and
wear of the cam followers.
What is the approximate position of the rotating magnet in a high tension magneto when the points first close?
Full register.
What is a result of “flashover” in a distributor?
Conductive carbon trail.
A spark plug’s heat range is the result of
its ability to transfer heat from the firing end of the spark plug to the cylinder head.
Defective spark plugs will cause the engine to run rough
at all speeds.
In an aircraft magneto system if the p-lead is disconnected, the magneto will be
on regardless of ignition switch position.
What are two parts of a distributor in an aircraft engine ignition system?
1. Coil
2. Block
3. Stator
4. Rotor
5. Transformer
2 and 4.
Ignition check during engine runup indicates excessive RPM drop during operation on the right magneto. The major portion of the RPM loss occurs rapidly after switching to the right magneto position (fast drop). The most likely cause is
faulty or fouled spark plugs.
Ignition check during engine runup indicates a slow drop in RPM. This is usually caused by
incorrect ignition timing or valve adjustment.
What is the radial location of the north poles of a four pole rotating magnet in a high tension magneto?
180° apart.
The capacitor type ignition system is used almost universally on turbine engines primarily because of its high voltage and
high heat intensity.
When timing a magneto internally, the alignment of the timing marks indicates that the
magnets are in the E gap position.
Capacitance afterfiring in most modern spark plugs is reduced by the use of
a built in resistor in each plug.
What components make up the magnetic system of a magneto?
Rotating magnet, the pole shoes, the pole shoe extensions, and the coil core.
In a turbine engine dc capacitor discharge ignition system, where are the high voltage pulses formed?
At the triggering transformer.
The primary advantage of pneumatic (air turbine) starters over comparable electric starters for turbine engines is
high power-to-weight ratio.
The secondary coil of a magneto is grounded through the
primary coil.
What are two parts of a distributor in an aircraft engine ignition system?
Block and rotor
Great caution should be exercised in handling damaged hermetically sealed turbine engine igniter transformer units because
some contain radioactive material.
If a spark plug lead becomes grounded, the
magneto will not be affected.
Aircraft magneto housings are usually ventilated in order to
provide cooling and remove corrosive gases produced by normal arcing.
A magneto ignition switch is connected
parallel to the breaker points.
