Ignition and starting systems Flashcards
What is a magneto
Self-contained AC generator driven by the engine for purpose of ignition in a reciprocating engine
Why are magneto ignition systems preferred over battery type ignition systems for reciprocating engines
Magnetos are independent ignition sources and do not rely on battery powered to provide ignition
What can cause a reciprocating engine to continue to run when the nation switch is in the off position
Break in the P lead wire
What is the purpose of the condenser in a high tension magneto electrical system
To prevent arcing at points and to hasten the collapse of the magnetic field around the primary coil
Where is E gap position
When the polls of the rotating magnet or a few degrees pass the neutral position. He gap is the position at which the points begin to open
What are the three major circuits of a high tension magneto system
Magnetic circuit, primary electrical circuit, secondary electrical circuit
What are the components of a high tension magnetic circuit
Magnetic circuit consist of a permanent rotating magnet, soft iron core, Pole shoes
What happens when the primary breaker points open in a magneto
Stop the flow of current in the primary coil
The magnetic field that was omitted by the primary coil collapse. As this magnetic field collapses, the flex line that cut across the windings of the secondary coil induce a pulse of high-voltage current in the secondary coil needed to fire the spark plug plug
What is the Piston position when the spark occurs in a cylinder
The piston is a specified number Of degrees Before top dead center on the compression stroke
What is a dual magneto
Incorporates to magnetos in one housing. They share the rotating magnet and cam, However they have their own set of points, coils, and distributor blocks
What is the difference between a low tension and high tension ignition system
Hi tension system, the high-voltage is generated in the magneto and flows to the plugs through a high tension lead
Low tension system the low-voltage his generated and the magneto and flows through a low tension lead to the primary winding of a transformer coil located near her each spark plug
When you ignition is off what is the condition of the primary circuit
It is completed through the ignition switch to ground
What three conditions are required to fire plugs in a cylinder when the piston is in the prescribed position
The magnetos Magnet polls must be in the E gap position, The breaker points must be open in the distributor rotor Must be aligned with a distributor electrode for that cylinder
What is a dual ignition system, and what part of the system is grounded when the ignition switch is placed in the right position
A dual ignition system uses to separate magnetos with the harness arranged so that each magneto fires one plug in each cylinder. If the switch is set a right, they left magneto will be grounded preventing it from firing
What is internal timing of a magneto
Adjusting the breaker points to open when the polls of the rotating magnet are at E gap position
What is the purpose of an impulse coupling used with a magneto
Used to retard the timing of the spark to after top dead center for starting the engine.
it provides a momentarily hi rotational speed to produce a spark at low crankshaft RPM
What is staggered ignition timing
It is the firing of one spark plug before the other instead of firing them simultaneously
What is the proper spark plug reach
When the electrode End of the plug inside the cylinder is in the best position to achieve ignition
Why is it important to keep track of the cylinders that spark plugs are installed in
Spark plugs can provide a lot of information about the health of a specific cylinder
What type ignition system is used in most turbine engine’s
Electric capacitor type ignition systems
What is the function of the igniter plug in a turbine engine
To provide a discharge gap for the current, which is stored in the capacitor.
They discharge results in a high intensely spark which ignite the fuel air mixture
When are turbine engine ignition system is normally in use
Only for starting a restarting an engine
What are two types of igniter plugs
Annular rum -Long reach plugs that extend into the combustion chamber
Constrained gap- A short reach plug that does not extend into the chamber because the spark does not remain close to the plug
What is the purpose of a dual magneto configuration
For redundancy and safety, in case one magneto fails
How can you tell if a starter communtator Is dirty or worn
Excessive noisey starter
What does it mean when the starter relay clicks when the starter switch is placed in the start position
The supply voltage is too low to supply enough current to the relay coil to fully engage the contact points
What is the advantage of air turban starters, when compared to electric starters, for large turbine engine’s
Light weight, and do not have the same cool down periods As electric starters
Why do turban igniters not get carbon filed as often as reciprocating engine spark plugs
Extremely high rates of electrical discharge in the turbine igniter
What are the three parts I have an ignition system of a turbine
Exciter, ignition Lead, and igniter
