Ignition and Starting Systems

Question 1

Name one general type of inertia starter.

Answer 1

Electric

Question 2

What is a magneto?

Answer 2

Self-contained AC generator driven by the engine for the purpose of ignition

Question 3

Why are magneto ignition systems preferred over battery type ignition systems for reciprocating engines?

Answer 3

Magnetos are an independent ignition source and do not rely on battery power to provide ignition

Question 4

What can cause a reciprocating engine to continue to run when the ignition switch is in the OFF position?

Answer 4

A break in the p-lead wire from the magneto to the switch

Question 5

What is the purpose of the condenser in a high-tension magneto electrical system?

Answer 5

To prevent arcing at the points and to hasten the collapse of the magnetic field around the primary coil

Question 6

What does a capacitor do in a magneto circuit?

Answer 6

Prevents arcing and hastens the collapse of the magnetic field about the primary coil

Question 7

Where is the E-gap position?

Answer 7

When the poles of the rotating magnet are a few degrees past the neutral position when the points begin to open

Question 8

What are the three major circuits of a high-tension magneto system?

Answer 8

Magnetic and Primary and Secondary Electrical

Question 9

What are the components of a high-tension magnetic circuit?

Answer 9

Permanent rotating magnet, soft iron core, and pole shoes

Question 10

What happens when the primary breaker points open in a magneto?

Answer 10

Stops the flow of current in the primary coil

Question 11

What is the position when the spark occurs in a cylinder?

Answer 11

A specified number of degrees before top dead center on the compression stroke

Question 12

What is a dual magneto?

Answer 12

Two magnetos in one housing that share the rotating magnet and cam

Question 13

What is the difference between a low tension and a high-tension ignition system?

Answer 13

In a High-Tension System, high voltage is generated in the magneto and flows to the plugs through high tension leads. In Low-Tension Systems, the low voltage is generated in the magneto and flows through the low tension leads

Question 14

When the ignition switch is in the OFF position, what is the condition of the primary circuit?

Answer 14

It is completed through the ignition switch to ground

Question 15

What three conditions are required to fire plugs in a cylinder when the piston is in the prescribed position?

Answer 15

The magneto’s magnet poles must be in the E-gap position, the breaker points must open, and the distributor rotor must be aligned with a distributor electrode for that cylinder.

Question 16

What is a dual ignition system and what part of the system is grounded when the ignition switch is placed in the RIGHT position?

Answer 16

A dual ignition system uses two separate magnetos with the harness arranged so that each magneto fires one plug in each cylinder. If the switch is set to RIGHT, the left magneto will be grounded, preventing it from firing.

Question 17

What is internal timing of a magneto?

Answer 17

Adjusting the breaker points to open when the poles of the rotating magnet are at the E-gap position

Question 18

What is the purpose of an impulse coupling used with a magneto?

Answer 18

To retard the timing of the spark to after top dead center for starting the engine

Question 19

What is staggered ignition timing?

Answer 19

Firing of one spark plug before the other

Question 20

What is the proper spark plug reach?

Answer 20

When the electrode end of the plug inside the cylinder is in the best position to achieve ignition

Question 21

Why is it important to keep track of the cylinder that spark plugs are installed in?

Answer 21

Spark plugs can provide a lot of information about the health of a specific cylinder

Question 22

What type of ignition system is used in most turbine engines?

Answer 22

Electronic Capacitor Type

Question 23

What is the function of the ignitor plugs in a turbine engine?

Answer 23

Provide a discharge gap for current, which is stored in the capacitor

Question 24

When are turbine engine ignition systems normally in use?

Answer 24

Only for starting or restarting an engine

Question 25

What are two types of ignitor plugs?

Answer 25

Annular gap - long reach, Constrained gap - short reach

Question 26

What is the purpose of the dual magneto configuration?

Answer 26

Redundancy and safety

Question 27

How can you tell if a starter commutator is dirty or worn?

Answer 27

Excessively noisy starter

Question 28

What does it mean when the starter relay clicks when the starter switch is placed in the START position?

Answer 28

Supply voltage is too low to supply enough current to the relay coil to fully engage the contact points

Question 29

What is an advantage of air-turbine starters when compared to electric starters for large turbine engines?

Answer 29

They are light weight and do not have the same cool down periods as electric starters

Question 30

Why do turbine ignitors not get carbon fouled as often as reciprocating engine spark plugs?

Answer 30

Due to extremely high rates of electrical discharge in the turbine ignitors

Question 31

What are three parts of an ignition systems of a turbine?

Answer 31

Exciter, Ignition Lead, Ignitor

Question 32

What is the difference between a temporary magnet and a permanent magnet?

Answer 32

A permanent magnet retains its magnetic properties for a long period of time. Temporary magnets act like permanent magnets when they are within a strong magnetic field

Question 33

What does the ignition light indicate when timing a magneto?

Answer 33

When the points are beginning to open

Question 34

In terms of the engine crankshaft position, when does the ignition event occur?

Answer 34

A specified number of crankshaft degrees before top dead center on the compression stroke

Question 35

What is the purpose of the capacitor in a magneto?

Answer 35

It prevents arcing at the points and aids in the collapsing of the magnetic field

Question 36

What is the main concern when preparing a magneto for installation?

Answer 36

Internal timing

Question 37

What are the three events required to fire a spark plug in a cylinder when its piston is in the prescribed position?

Answer 37

Magneto in E-gap position, Breaker points opening, Distributor electrically aligned with that cylinder

Question 38

What is the function of a duty cycle in relation to a turbine engine ignition system?

Answer 38

A duty cycle allows the operation of the ignition system for a given amount of time, to be followed by a minimum specified cooling down period

Question 39

Name 3 sources of high volume, low pressure compressed air commonly used for starting jet transport aircraft equipped with air turbine starters.

Answer 39

APU, GPU, Compressed Bleed Air

Question 40

Name two parts of a starter generator that commonly require periodic inspection to ensure that they do not wear beyond operational limits.

Answer 40

Commutator and brushes

Question 41

Between the field and armature windings in starter generator, which ordinarily receive current from operation in the start mode?

Answer 41

Both the field and the armature

Question 42

What are the three components of a spark plug?

Answer 42

Electrode, Insulator, Bore

Question 43

Spark plug leads perform 2 functions; what are those functions?

Answer 43

Carry the voltage and shield the power from radios.