Electrical System Breaker Function Quiz

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Questions and Answers

What is the function of the stationary breaker point in the primary electrical circuit?

To provide an adjustable timing mechanism for ignition (correct)

To reduce corrosion on the cam follower

To connect the cam follower directly to the rotor shaft

To generate electrical current when points are closed

Which component is responsible for forcing the movable breaker contact away from the stationary contact?

The cam follower (correct)

The felt oiler pad

The metal leaf spring

The magneto rotor shaft

How does the felt oiler pad contribute to the operation of the electrical system?

It connects the cam follower to the rotor

It lubricates and prevents corrosion on the cam (correct)

It adjusts the timing of the breaker points

It prevents wear of the breaker contacts

What material is typically used for the cam follower in the primary electrical circuit?

Micarta block Signup and view all the answers

Which mechanism drives the breaker-actuating cam in the electrical system?

A gear train from the rotor shaft Signup and view all the answers

What occurs at the moment when the breaker points are closing in the ignition system?

A maximum amount of flux is passing through the coil core. Signup and view all the answers

What timing mechanism is responsible for the opening and closing of the breaker points?

The breaker cam. Signup and view all the answers

At which point does the magnetic rotor open the breaker points?

After reaching the neutral position. Signup and view all the answers

What does the top of Figure 4-7 represent?

The original static flux curve of the magnets. Signup and view all the answers

What is the primary purpose of the condenser in the electrical circuit?

To store electrical energy for discharge. Signup and view all the answers

Which of the following best describes a FADEC system?

It is an electronic control system for reciprocating engines. Signup and view all the answers

What is a key characteristic of high-tension magneto systems?

They are widely used due to advancements in technology. Signup and view all the answers

What is the primary reason low-tension magneto systems are now rare?

Advancements in materials and shielding have rendered them obsolete. Signup and view all the answers

How does a magneto generate current?

Through the interaction of a moving permanent magnet and a coil of wire. Signup and view all the answers

Which statement is true regarding the throttle input in FADEC systems?

Throttle input is primarily controlled electronically. Signup and view all the answers

What differentiates high-tension from low-tension magneto systems?

High-tension systems use higher voltage outputs. Signup and view all the answers

What does the acronym FADEC stand for?

Full Authority Digital Engine Control Signup and view all the answers

What type of generator is a magneto classified as?

Engine-driven alternate current generator Signup and view all the answers

What happens to the flux in the primary coil when current ceases to flow?

It decreases to zero. Signup and view all the answers

How does the primary current affect the magnetic field during the ignition process?

It prevents the field from changing. Signup and view all the answers

What role does the condenser play when the breaker points open?

It helps interrupt the current flow. Signup and view all the answers

What phenomenon occurs right after the spark discharge?

A series of small oscillations appear. Signup and view all the answers

What effect does the high-voltage in the secondary winding have during ignition?

It ignites the fuel/air mixture. Signup and view all the answers

What occurs as the magnet rotor reaches the position before the breaker points open?

High stress builds up in the magnetic circuit. Signup and view all the answers

Which of the following best describes the condition of the spark after it initially occurs?

It lasts for a brief moment only. Signup and view all the answers

What happens when voltage in the secondary winding becomes too low?

The oscillations cease. Signup and view all the answers

What causes the spark to follow a carbon track to the ground instead of reaching the spark plug?

Carbon provides an alternative path for current when moisture evaporates. Signup and view all the answers

Which of the following factors contributes to reducing the tendency of flashover in magnetos?

Adequate drainage and proper ventilation Signup and view all the answers

Why can magnetos not be hermetically sealed?

Changes in altitude affect pressure and temperature. Signup and view all the answers

In what scenario does flashover become more likely?

At high altitudes due to lower air pressure. Signup and view all the answers

What role does good magneto circulation play in an ignition system?

Carries away corrosive gases produced by arcing. Signup and view all the answers

What is essential in some magneto installations to prevent flashover during high altitude flight?

Pressurization of internal components Signup and view all the answers

What is the consequence of carbon tracking in an ignition system?

Impaired ignition leading to failure of cylinder firing. Signup and view all the answers

Which of the following is a normal byproduct of arcing within the distributor air gap?

Ozone Signup and view all the answers

What is the maximum voltage that can be generated in the secondary circuit of high-tension magnetos?

20,000 volts Signup and view all the answers

What are the two main components of a distributor?

Distributor rotor and distributor block Signup and view all the answers

In a secondary circuit, what role does the distributor rotor play during ignition?

It directs the high voltage to the spark plug Signup and view all the answers

How does the orientation of the distributor rotor affect ignition in the cylinders?

It aligns with the electrode in the distributor block Signup and view all the answers

What material is the distributor rotor typically made of?

Non-conducting material Signup and view all the answers

Why does the distributor rotate at one-half crankshaft speed in four-stroke cycle engines?

To synchronize with the spark plug firing Signup and view all the answers

What is the purpose of the high voltage in the secondary circuit when it reaches the spark plug?

To ignite the fuel/air mixture Signup and view all the answers

What does the term 'circumferentially' refer to in the arrangement of electrodes around the distributor block?

In a circular pattern Signup and view all the answers

What happens when the breaker points in the secondary circuit open?

The secondary voltage is induced Signup and view all the answers

How many electrodes does the distributor block have in relation to the engine's cylinders?

Equal to the number of cylinders Signup and view all the answers

Study Notes

Reciprocating Engines AVIA 1065 Ignition Systems

Reciprocating engines utilize ignition systems to deliver high-tension sparks across spark plug electrodes.
The spark timing needs to be precise in each cylinder, following the correct firing order.
The spark must happen before the top dead center position of the piston.
The output voltage of the system must be sufficient to arc across the spark plug-electrode gap under all operational conditions.
The spark plug threads into the cylinder head, exposing its electrodes to the combustion area.

Engine Ignition and Electrical Systems

Basic ignition system requirements are similar, regardless of the engine type.
Systems need to fire sparks in the correct cylinder order.
Appropriate spark timing is crucial; it occurs degrees ahead of top dead center.
Sufficient output voltage is needed for adequate spark across gaps in spark plugs.
Spark plugs need to be threaded correctly into the cylinder head for optimal performance.

Two Ignition System Classifications

Magneto-ignition systems are a common type.
Magneto systems for a single engine might consist of one magneto with the necessary wiring alongside another.
Dual magneto systems often feature one rotating magnet serving more than one magneto.
Another set of ignition systems are those using electronic controls called Full Authority Digital Engine Controls or FADEC.

Magneto-Ignition System Operating Principles

The magneto is a special type of engine-driven alternating current (AC) generator.
The magneto employs a permanent magnet as its energy source.
Current generation happens due to the movement of a wire coil within a magnetic field.

Engine Ignition and Electrical System Components

Magneto Unit: Contains the components that generate and deliver the spark.
Spark Generation: Components generating the spark.
Condenser: Stores electrical energy to enhance the spark's intensity.
Contact Breaker: Opens and closes the circuit to control the timing of the spark and regulate current.
Coil: Conducts and stores energy to intensify the spark.
Ignition Switch: Controls the flow of electricity for the ignition system.

Recip Engine Ignition Systems- Operation

High tension magneto operation relies on a distributor block, gears, various bearings, and a cam.
Timing for a high-tension magneto system is reliant on components such as output coils, distributor gears, and a cam.
The distributor block, a major component, is involved with the operation.
All components involved in the operation of the ignition system for a reciprocating piston engine need precise timing and cooperation from the cam, output coils and gears and bearings.

Engine Ignition and Electrical Systems - Magnetic Circuit

The magnetic circuit in a magneto device consists of a rotating multi-pole magnet, a soft iron core, and pole shoes.
This setup creates magnetic lines of force which in turn generate an electrical voltage.
The poles of the magnet are arranged alternatingly, allowing the flux to move from north to south through the coil core.

Primary Electrical Circuit

The primary coil's electrical configuration includes a coil, breaker contacts, and a condenser positioned in parallel to the breaker contacts.
The primary circuit is complete only when the ungrounded breaker contact touches the grounded breaker point.
A condenser(capacitor) is included in the primary circuit, crucial for preventing arcing at the contacts when it's opened.
The use of the condenser hastens the magnetic field collapse in the primary coil circuit.

Secondary Electrical Circuit

The secondary circuit components include a secondary coil, distributor, rotor, distributor cap, ignition electrical lead to spark plug.
The secondary coil creates high voltage electricity.
As the rotor turns and the breaker points open, the secondary coil receives energy generating a flux change causing a voltage pulse.
The voltage is distributed through the distributor rotor to the relevant spark plug.
The number of windings in the secondary coil dictates the high voltage output produced.

Magneto and Distributor Venting

Proper venting of magneto systems, which might incorporate drains and ventilation systems, maintains consistent circulation of gases and prevents moistures from condensing inside components preventing corrosion and damage.
Moisture inside the magneto components will create problems for the ignition system operation.
This is especially vital at high altitudes and with turbocharged engines, where there's less air pressure, which causes voltage to more readily jump the gaps.

Summary

Various components work together in detailed sequence to generate electrical energy for the spark plug ignition.
Different types of ignition systems exist, each with their own unique components and operating principles.
Understanding the intricacies of both primary and secondary circuits is vital for troubleshooting and maintenance of reciprocating engine ignition systems.

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Description

Test your understanding of the primary electrical circuit, focusing on components such as breaker points, felt oiler pads, and the role of the condenser. This quiz covers the mechanisms driving the operation of electrical systems including magneto systems and FADEC. Perfect for students and technical enthusiasts.