The Function and Mechanism of The Starter

The Function of the Starter Motor

What is the function of a starter motor? The starter is also called a motor, which converts the electrical energy of the battery into mechanical energy and drives the engine flywheel to rotate to start the engine. The starter is divided into DC starter, gasoline starter, compressed air starter, and so on according to the working principle. Most internal combustion engines use DC starters, which are characterized by compact structure, simple operation, and easy maintenance.

The gasoline starter is a small gasoline engine with a clutch and a transmission mechanism. It has high power and is less affected by the temperature. It can start a large internal combustion engine and is suitable for high and cold areas.

Compressed air starters are divided into two categories, one is to drive compressed air into the cylinder according to the working order, and the other is to use an air motor to drive the flywheel. The use of compressed air starters is close to that of gasoline starters and is usually used for starting large internal combustion engines.

The DC starter is composed of a DC series motor, a control mechanism, and a clutch mechanism. It specifically starts the engine and needs a lot of torque, so the amount of current to pass is huge, up to several hundred amps.

The DC motor has a large torque at low speed, and gradually decreases when the speed is high, which is very suitable for use as a starter.

The Principle of the Starter Motor

The starter adopts a DC series-excited motor, and the rotor and stator parts are wound with relatively thick rectangular cross-section copper wires; the driving mechanism adopts a reduction gear structure; the operating mechanism adopts an electromagnetic magnetic attraction method.

As we all know, the starting of the engine needs the support of external force, and the car starter plays this role. Generally speaking, the starter uses three components to implement the entire start-up process. The DC series motor introduces the current from the battery and causes the drive gear of the starter to produce mechanical motion; the transmission mechanism meshes the drive gear into the flywheel ring gear, the flywheel drives the crankshaft to rotate and, can be automatically disengaged after the engine is started; the starter circuit is switched on and off by an Electromagnetic switch to control. Among them, the motor is the main component inside the starter, and its working principle is the energy conversion process based on Ampere's law that we encountered in junior high school physics, that is, the effect of the force on the current conductor in the magnetic field. The motor includes the necessary armatures, commutators, magnetic poles, brushes, bearings, and housings. Before the engine can run on its power, it must be rotated by external force. The process in which the engine transitions from a static state to a self-running state with the help of external force is called the starting of the engine. There are three types of engine starting methods: manual starting, auxiliary gasoline engine starting, and electric starting. The manual starting method adopts rope pulling or hand cranking, which is simple but inconvenient and labor-intensive. It is only suitable for some low-power engines and is only reserved as a backup method in some cars; auxiliary gasoline engine starting is mainly used in high-power engines. On the diesel engine; the electric starting method is easy to operate, quick to start, can start repeatedly, and can be controlled from a long distance, so it is widely used in modern cars.

Institutional Features

The P11C engine deceleration starter has the following salient features:

① The power output structure is divided into two parts: the armature shaft and the transmission shaft. Both ends of the armature shaft are supported by ball bearings, the load distribution is uniform, the use time is long, and it is not easy to wear. The armature is short, and it is not easy to bend the armature shaft and wear out the magnetic field winding.

②A reduction gear is adopted, and a reduction gear is installed between the rotor and the starting gear, and the torque transmitted by the starting motor to the starting gear will increase. Using the electromagnetic switch, the power output of the motor (after the reduction gear) is the starting gear and the starting gear shaft, and the mesher part does not move. The starter with low output power often adopts the external meshing method, and the starter with large output power adopts the internal meshing method.

③ The deceleration starter is operated by an electromagnetic switch, and some are equipped with an auxiliary switch (or auxiliary switch). Its function is to prevent the burning of the electromagnetic switch and the electric gate (starting) switch. The power supply is switched on in stages, which greatly reduces the possibility of damage to the starter, thereby extending the service life of the starter.

④ The volume and weight of the deceleration starter are about half of those of the traditional starter, which saves raw materials and is convenient for disassembly and repair.

⑤ The number of pole pairs of the deceleration starter is the same as that of the traditional starter, but the magnetic field coil winding often adopts the method of connecting multiple small wires in series. Although the winding method of the armature winding is the same as the traditional principle, the manufacturing process is advanced.

Starter Motor Composition

The motor consists of a magnetic field (stator), an armature (rotor), and a commutator. To increase the torque, a multi-pole magnetic field is used, and there are four common magnetic fields.

When current is passed through the armature coil, the entire coil will be rotated by a torque. After the DC motor is energized, a back electromotive force will be generated, which is proportional to the engine speed and inversely proportional to the torque, so it can meet the requirements when the engine is started and drive the piston to move up and down. The starting current of the starter is very large, so the starting time must be short during operation.

Reduction Mechanism

The drive gear of the reduction gear mechanism is engaged with the engine flywheel to start the engine, and a one-way drive is adopted. When the speed of the pinion on the motor is higher than the speed of the flywheel ring gear of the engine, the motor drives the engine to rotate, and when the speed of the engine is higher than that of the motor, the power transmission relationship between them is automatically released.

The deceleration starter is mainly composed of an electromagnetic meshing switch, reduction gear, motor, starting gear (pinion), and one-way meshing device as shown.

Institutional Installation

Clean the armature and external drive mechanism with gasoline first. After cleaning, see if the drive is flexible; during installation, graphite grease should be applied between the friction plates of the friction clutch, and oil should be applied to the threaded part; the starter is installed on the engine, and the distance between the end face of the drive gear and the plane of the flywheel is 3— 5 mm is suitable to ensure the correct meshing of the gears.

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In conclusion, the starter motor and its driving mechanism are key components in the engine starting process. It converts electrical energy into mechanical energy to make your heavy equipment roar. For various types of starters, including DC starters, gasoline starters, and compressed air starters, these starters can ensure smooth ignition of your engine. Understanding the inner workings and construction of these starters is important for both maintaining and troubleshooting heavy equipment.