An electric motor starter is a crucial component in starting the internal combustion engine in a vehicle. It is responsible for converting electrical energy from the battery into the mechanical energy required to crank the engine and start it running. The starter motor is composed of several key components, each with its specific function, that work together to perform this task. In this article, we will discuss the main components of a starter motor and their functions, including the armature, commutator, brushes, solenoid, lever fork, pinion, and field coils. Understanding these components and how they work together is essential for anyone who wants to have a basic knowledge of how an electric motor starter functions.
Armature
The armature of an electric motor is the rotating component that generates a magnetic field as it rotates within a stationary magnetic field produced by the stator (the stationary component of the motor).
When electrical energy is applied to the armature, it creates a magnetic field that interacts with the magnetic field of the stator, causing the armature to rotate. The armature typically consists of a metal core, wound with wire to form coils, and mounted on a shaft that is supported by bearings.
Commutator
The commutator is a component of a direct current (DC) electric motor that is responsible for reversing the current in the armature coils as the armature rotates.
The commutator consists of a cylindrical structure made of copper segments, which are insulated from each other, and mounted on the armature shaft. The armature coils are connected to the commutator segments, and as the armature rotates, the commutator segments change position concerning the brushes that supply electrical current to the armature.
The commutator ensures that the current in the armature coils always flows in the correct direction, allowing the magnetic field generated by the coils to continuously interact with the magnetic field of the stator and maintain the rotation of the armature.
Brushes
The brushes of an electric motor are sliding contacts that transfer electrical current from a fixed power source to the moving parts of the motor, specifically the commutator.
The brushes are typically made of graphite or carbon and are held in contact with the commutator by springs. They transfer the electrical current to the rotating commutator, which in turn distributes the current to the armature coils. The brushes also help to collect the current generated in the armature coils and transfer it back to the power source.
The brushes play a critical role in the operation of a direct current (DC) electric motor, ensuring a continuous flow of electrical current to the armature and maintaining the rotation of the motor.
Solenoid
A solenoid is an electromechanical device that converts electrical energy into linear mechanical force.
A solenoid consists of a coil of wire that creates a magnetic field when electrical current flows through it. When a current is applied to the solenoid, the magnetic field generated by the coil attracts a ferromagnetic core or plunger, which is then pushed or pulled into the coil. The linear motion of the core or plunger can be used to perform work, such as opening or closing a valve, operating a switch, or controlling a mechanism.
Solenoids are commonly used in a wide range of applications, including control systems, automotive and industrial equipment, and electrical appliances.
Plunger
The plunger of a solenoid is a cylindrical component that moves within the solenoid’s coil in response to changes in the magnetic field generated by the current flowing through the coil.
The plunger is typically made of a ferromagnetic material, such as iron, and its movement is used to perform work, such as opening or closing a valve, operating a switch, or controlling a mechanism. When a current is applied to the solenoid, the magnetic field generated by the coil attracts the plunger into the coil, producing linear motion.
The plunger is an important component of a solenoid, as it is responsible for the solenoid’s ability to convert electrical energy into linear mechanical force.
Lever Fork
A lever fork is a mechanical component that converts rotary motion into linear motion. It typically consists of two arms that are pivoted at one end and connected at the other end to a link or rod.
In an electric motor starter, the lever fork is used to engage and disengage the starter motor with the engine of a vehicle. When the starter motor rotates, the lever fork moves linearly, pushing or pulling a pinion gear into or out of mesh with a ring gear on the engine. This motion is used to crank the engine and start it running.
The lever fork is an important component of an electric motor starter, as it allows the starter motor to engage and disengage the engine in a controlled and reliable manner.
Pinion
The pinion is a small, cylindrical gear that is used in an electric motor starter to transfer rotary motion from the starter motor to the engine of a vehicle.
The pinion gear is typically mounted on the end of a lever fork, which converts rotary motion into linear motion. When the starter motor rotates, the lever fork moves linearly, pushing the pinion into mesh with a ring gear on the engine. This causes the engine to rotate, cranking it and starting it running.
The pinion is an important component of an electric motor starter, as it allows the starter motor to transfer rotary motion to the engine and start it running.
Field Coils
The field coils of an electric motor are a set of stationary coils that generate a magnetic field used to interact with the armature to produce rotary motion.
The field coils are typically wound around a magnetic core, such as a ferromagnetic pole, and are connected to a DC power source. When current flows through the field coils, it creates a magnetic field that interacts with the magnetic field generated by the armature coils to produce rotary motion.
The field coils are an important component of an electric motor, as they play a key role in determining the motor’s torque, speed, and efficiency.
