The contact breaker system, also known as a points ignition system, is a crucial component in the ignition process of internal combustion engines. It was widely used in vehicles manufactured from the early 20th century up until the 1970s, when electronic ignition systems started to become more prevalent. In this blog, we will discuss what the contact breaker system is, how it works, and its advantages and disadvantages.

What is a Contact Breaker System?

A contact breaker system is a type of ignition system that uses a mechanical switch called a “breaker” or “points” to open and close the electrical circuit that delivers the spark to the engine’s cylinders. The contact breaker system consists of four main components:

  1. Distributor: A component that distributes high voltage spark from the ignition coil to each spark plug in the correct firing order.
  2. Ignition Coil: A high voltage transformer that converts the low voltage from the battery to the high voltage required to create a spark at the spark plugs.
  3. Contact Breaker: A mechanical switch that opens and closes the circuit between the ignition coil and the distributor.
  4. Capacitor: A component that helps to reduce arcing and prolong the life of the contact breaker.

How does it work?

The contact breaker system works by using the rotation of the engine’s camshaft to open and close the contact breaker. The camshaft has a lobe that pushes against a lever attached to the contact breaker, causing it to open and close. When the contact breaker is closed, it allows the low voltage from the ignition coil to flow through the primary winding of the coil and build up a magnetic field. When the contact breaker opens, it interrupts the flow of current, causing the magnetic field in the coil to collapse. This collapsing magnetic field induces a high voltage in the secondary winding of the coil, which is then sent to the distributor and on to the spark plugs.

Advantages of a Contact Breaker System:

  1. Simple design: The contact breaker system is relatively simple and straightforward to understand, and its components are easy to maintain and replace.
  2. Low cost: Compared to electronic ignition systems, the contact breaker system is less expensive to manufacture and repair.
  3. Robust: The contact breaker system is less susceptible to damage from high temperatures and electromagnetic interference, making it suitable for use in harsh environments.

Disadvantages of a Contact Breaker System:

  1. Maintenance: The contact breaker system requires regular maintenance, such as cleaning and adjusting the points, to ensure that it is working correctly.
  2. Limited lifespan: The contact breaker system has a limited lifespan due to the wear and tear of the contact points, which can eventually lead to a loss of performance or failure.
  3. Inaccurate timing: The accuracy of the ignition timing in a contact breaker system can be affected by wear and tear on the mechanical components, which can lead to poor engine performance or damage.

Conclusion:

The contact breaker system is an essential component of the ignition system in internal combustion engines. While it has some advantages, such as its simplicity and low cost, it also has some disadvantages, such as requiring regular maintenance and having a limited lifespan. Despite being widely used in the past, electronic ignition systems have largely replaced contact breaker systems in modern vehicles due to their increased accuracy and reliability. However, the contact breaker system remains an important part of automotive history and is still used in some vintage and classic cars today.

How the Contact Breaker System Works:

The operation of the contact breaker system can be broken down into four main stages: charging, dwell, ignition, and exhaust.

  1. Charging: The ignition coil is charged with a low voltage from the battery through the primary winding. As the engine rotates, the camshaft moves the breaker points to the closed position, completing the circuit.
  2. Dwell: With the circuit closed, the ignition coil charges up and stores energy in the magnetic field. This is the “dwell” period, which is the length of time the points stay closed.
  3. Ignition: When the camshaft rotates and opens the breaker points, the circuit is broken, causing the magnetic field in the ignition coil to collapse. This sudden collapse induces a high voltage in the secondary winding, which is sent to the distributor and then to the spark plugs, creating a spark that ignites the fuel-air mixture in the cylinder.
  4. Exhaust: The burned fuel-air mixture is expelled from the cylinder during the exhaust stroke, and the process repeats itself for the next cylinder in the firing order.

Advantages of the Contact Breaker System:

  1. Simple and Reliable: The contact breaker system is relatively simple and robust, consisting of only a few mechanical components that are easy to maintain and repair. With proper maintenance, the contact breaker system can be very reliable.
  2. Low Cost: The contact breaker system is less expensive to manufacture and repair compared to electronic ignition systems.
  3. Compatible with Multiple Fuel Types: The contact breaker system is compatible with different fuel types and can be used with a wide range of internal combustion engines.

Disadvantages of the Contact Breaker System:

  1. Maintenance: The contact breaker system requires regular maintenance to keep the ignition timing accurate and the breaker points clean and properly adjusted.
  2. Wear and Tear: The breaker points are subject to wear and tear, which can cause the ignition timing to become inaccurate, leading to poor engine performance and increased emissions.
  3. Limited Lifespan: The contact breaker system has a limited lifespan due to the wear and tear on the breaker points and other mechanical components, which can lead to the system’s failure.

Conclusion:

The contact breaker system played a significant role in the development of the internal combustion engine and was widely used in vehicles from the early 1900s until the 1970s. While it has some advantages, such as its simplicity and reliability, it also has some disadvantages, such as requiring regular maintenance and having a limited lifespan. Despite being replaced by electronic ignition systems in modern vehicles, the contact breaker system remains an important part of automotive history and is still used in some vintage and classic cars today.

Advantages of the Contact Breaker System:

  1. Simplicity: The contact breaker system is relatively simple, consisting of only a few mechanical components, making it easy to understand, maintain, and repair. This simplicity also makes the system more reliable as there are fewer components that can fail.
  2. Cost: Compared to electronic ignition systems, the contact breaker system is less expensive to manufacture and repair. This makes it a more cost-effective option for older vehicles or those with lower budgets.
  3. Compatibility: The contact breaker system is compatible with a wide range of internal combustion engines and can work with multiple fuel types, including gasoline, diesel, and LPG.

Disadvantages of the Contact Breaker System:

  1. Maintenance: The contact breaker system requires regular maintenance to keep the ignition timing accurate and the breaker points clean and properly adjusted. Failure to do so can result in poor engine performance and increased emissions.
  2. Wear and Tear: The breaker points are subject to wear and tear, which can cause the ignition timing to become inaccurate, leading to poor engine performance and increased emissions. Additionally, the mechanical components of the system can wear out over time, leading to system failure.
  3. Limited Lifespan: Due to the wear and tear on the breaker points and other mechanical components, the contact breaker system has a limited lifespan. Eventually, the system will need to be replaced or upgraded to an electronic ignition system for improved performance and reliability.

In conclusion, the contact breaker system has its advantages, including simplicity, cost, and compatibility. However, it also has some disadvantages, including maintenance requirements, wear and tear, and a limited lifespan. While still used in some vintage and classic cars today, electronic ignition systems have largely replaced the contact breaker system in modern vehicles.

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