Ignition & Starting Systems

Question 1

1. What is a magneto?

Answer 1

Self contain AC generator that provides ignition to the engine

Question 2

2. Why are magneto ignition systems preferred over battery type ignition systems for reciprocating engine?

Answer 2

Magnetos are independent ignition source & do not rely on battery power

Question 3

3. What can cause a reciprocating engine to continue to run when ignition is in the off position?

Answer 3

P-lead break needs ground to shut off

Question 4

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

Answer 4

Prevent arcing at the points & hasten magnetic field around primary coil

Question 5

5. Where is the e gap position?

Answer 5

Poles of rotating magnet are few degrees past neutral
Points start to open

Question 6

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

Answer 6

Magnetic
Primary
Secondary

Question 7

7. What are the components of a high tension magnetic circuit?

Answer 7

Permanent rotation magnet
Soft iron core
Pole shoes

Question 8

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

Answer 8

Stops flow of current in primary coil
Magnetic field collapses creating induce pulse of high voltage current creating spark

Question 9

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

Answer 9

Specified # of degrees before TDC

Question 10

10. What is a dual magneto?

Answer 10

Two magnetos in one housing

Question 11

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

Answer 11

High tension - high voltage from magneto to plugs
Low voltage - low voltage from magneto to transformer coil near plug then increased to high

Question 12

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

Answer 12

Completed through ignition switch to ground

Question 13

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

Answer 13

E gap
Breaker points open
Distributor rotor aligned with electrode

Question 14

14. 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 14

The left magneto is grounded meaning OFF

Question 15

15. What is internal timing of a magneto?

Answer 15

Adjusting the breaker points to open with poles of magnet

Question 16

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

Answer 16

Retard the timing of the spark till after TDC for starting

Question 17

17. What is staggered ignition timing?

Answer 17

Fires one spark plug before the other vs all at same time

Question 18

18. What is the proper spark plug reach?

Answer 18

When electrode end of the plug inside the cylinder is in the best opposition for ignition

Question 19

19. Why is it important to keep track of the cylinders that spark plug are installed in?

Answer 19

Spark plugs provide health information about that cylinder

Question 20

20. What type ignition system is used in most turbine engines?

Answer 20

Electronic capacitor type ignition system

Question 21

21. What is the function of the igniter plugs in a turbine engine?

Answer 21

Provide discharge gap for current

Question 22

22. When are turbine engine ignition system normally used?

Answer 22

For starting or restarting

Question 23

23. What are two types of igniters plugs?

Answer 23

Annular gap
Constrained gap

Question 24

24. What is the purpose of the dual magneto configuration?

Answer 24

Redundancy

Question 25

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

Answer 25

Excessively noisy starter

Question 26

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

Answer 26

Supply voltage too low

Question 27

27. What is an advantage of air turbine starters, when compared to electric starter, for large turbine engines?

Answer 27

Light weight

Question 28

28. Why do turbine igniters not get carbon fouled as often as reciprocating singe spark plugs?

Answer 28

Due to High rates of electrical discharge

Question 29

29. What are the three parts of an ignition system of a turbine?

Answer 29

Exciter Ignition lead Igniter

Question 30

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

Answer 30

Permanent retains its magnetic properties Temporary acts as permanent when within magnetic field of permanent magnet