Ignition And Starting Systems

Question 1

What is a shower of sparks ignition system?

Answer 1

An ignition system that uses an indication vibrator to send pulsating DC into a set of retard breaker points on one of the magnetos. This provides a hot and retarded, spark for starting the engine.

Question 2

What is an impulse coupling and how does it work?

Answer 2

A impulse coupling is a spring loaded coupling between a magneto shaft and the drive gear inside the engine when the engine is rotated for starting the impulse coupling locks the magnet so it cannot turn the coupling up as the crankshaft continues and the piston top dead, the coupling releases and spins the magnet producing hot and retarded spark

Question 3

What kind of electric starting system is used on many of the smaller turbine engines

Answer 3

A starter generator

Question 4

Why are air turbine starter superior to electric starters for large turbine engines?

Answer 4

They are lightweight for torque they produce

Question 5

Where does an air turbine starter get its air for starting the engines on a jet transport airplane?

Answer 5

From an APU GPU from a running engine

Question 6

What prevents too high and air pressure for over speeding and air turbine starter

Answer 6

The air shut off and regulating valve

Question 7

Where does an air turbine starter get its lubricating oil?

Answer 7

It has a self-contained lubrication system with the oil held in the starter housing

Question 8

What device in an air turbine starter warns an aviation mechanic if there are any metal chips or particles in the oil

Answer 8

Magnetic chip detectors, worn of any metal contamination in the oil 

Question 9

What is the function of the capacitor in a magneto?

Answer 9

The capacitor minimizes arcing at the breaker points and its speeds of the collapse of the primary current as the breaker points

Question 10

What happens in a magneto ignition system when the ignition switch is placed in the off position

Answer 10

The primary circuit is connected to the ground

Question 11

What is checked when a magneto is internally timed

Answer 11

Internally timing, a magneto consist of adjusting the breaker points so they will open at the instant the rotating magnet is in its E gap position and the distributor rotator is in position to direct the high voltage to cylinder number one

Question 12

In what position should the ignition switch be placed when using a timing light on the magnetos?

Answer 12

In the both position

Question 13

What is the E gap in a magneto timing?

Answer 13

The E gap angle is the position of the rotating magnet where the primary current flowing in the magneto coil is the greatest

Question 14

What malfunction in the ignition system would cause an aircraft reciprocating engine to continue to run after the ignition switch is placed in the off position

Answer 14

The ignition switch is not grounding, the magnet primary circuit

Question 15

What type of ignition system is used on most turbine engine?

Answer 15

High intensity, intermittent duty, capacitor, discharge ignition systems

Question 16

How many igniters are used with most turbine engines?

Answer 16

2

Question 17

What are two types of ignition systems used in turbine engines?

Answer 17

High voltage system and low voltage systems

Question 18

With which type of turbine engine ignition systems is a glow plug igniter used

Answer 18

Low-voltage system

Question 19

How is the strength of the magneto checked?

Answer 19

The magneto is put on a test stand and rotated at a specific speed. The breaker points are held open, and the primary current is measured the strength of the magnet determines the amount of primary current.

Question 20

In what position is the magnet in the magneto when the greatest change in flux density in the coil core takes place

Answer 20

It is a few degrees beyond neutral position

Question 21

In what position is the magnet in a magneto when the breaker points begin to open?

Answer 21

And it’s E gap position

Question 22

What happens when they start switch for a turbine engine with a starter generator is placed in the start position

Answer 22

Current flows into the starter relay which closes an actuates, the ignition exciter
Current flows through the series coils of the starter generator and rotates the engine until it starts

Question 23

What happens when the start switch for a turbine engine with a starter generator is placed in the run position

Answer 23

The starter relay opens
The generator field relay is closed
The output of the generator flows to the bus through the generator circuit breaker

Question 24

What is indicated if the starter relay chatters rather than locks in when the start switch is placed in the start position?

Answer 24

The battery voltage is too low to supply enough current to hold the relay engaged

Question 25

What is the purpose of the sheer section in a air turbine driveshaft?

Answer 25

The ratchet mechanism fails to release, and the engine drives the starter to a speed higher than it’s design. Speed section will break and disconnect the starter from the engine.