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  1. Technology

Starter

The automotive starter is a key component of the engine cranking system, responsible for starting the vehicle. It is an electrical device that converts electrical energy from the battery into the mechanical energy required to crank the engine.

The key component of the starter is an electric motor fitted with a one-way clutch. When the car is started, the starter motor rotates the crankshaft of the engine, giving it speed. The electrical energy from the battery is converted into mechanical energy, allowing the engine to run autonomously.

There are mainly electric starters on the market, which are the most common in modern vehicles. However, it is also possible to find internal combustion starters and pneumatic starters, which are used in specific applications.

Starter construction

  1. Slip sleeve
  2. Overrunning clutch limiter
  3. Pinion
  4. Overrunning clutch
  5. Lever
  6. Solenoid starter switch
  7. Electrical connection
  8. Slip sleeve
  9. Brushes
  10. Commutator
  11. Electric rotor
  12. Stator
  13. Frame
  14. Starter spring

Typical signs of a faulty starter motor

Overheating

If the starter motor "won't turn", makes a noise, or operates with too little power to turn the crankshaft fast enough, it has probably been overheated. The starter is a DC motor designed to run for short periods of time. Manufacturers of first-assemblies specify that it should run for a maximum of about 15 seconds. After that, it deserves a break of at least two minutes. Few drivers are able to follow these rules when their car won't start.
Internal damage

The Bendix not only moves the clutch mechanism towards the pinion (to drive the engine flywheel), but also pulls it back at the right moment (when the engine reaches a higher rpm than the starter). A fault in the electrical installation can lead to a lack of return stroke, in which case the engine speed is transmitted to the pinion. The result is complete destruction of the starter components.
Corrosion

Rust is the enemy of all electrical systems. Even a small amount of moisture in the starter can be the cause. Simply put, corroded components lose their mechanical and electrical properties. How does moisture get into the starter? The culprit is usually a missing flywheel cover or leaks caused by harsh operating conditions. It can also be caused by water ingress, which can also be considered mechanical damage, as described in the next section.
Mechanical damage

The starter is at risk of becoming flooded or contaminated when the vehicle is used in severe conditions, such as off-road driving. However, the most common external damage to the starter is not caused by harsh working conditions, but by installation errors.

The most common problems are

Incorrect starter selection
Improper installation procedures
Incorrect bolt tightening