The starter is the most important element of the car. The main task is on his shoulders - starting the engine. But, like any DC motor, the starter is not very reliable. Sometimes it breaks down, so repair or replacement is required.
Somehow you don't think too much about how car systems work. Until something breaks down. And that something is often a starter, which is designed to start the engine. Most often, its mechanical part breaks down, a little less often the electrical one. To carry out diagnostics and repairs, you need to know the principle of operation of the starter and its main components. And small, at least general, knowledge in electrical engineering will not be superfluous. So what are the main components of the starter and why does it spin only when the key is turned all the way?
Device and principle of operation
The starter is a DC motor, it has two windings (rotor and stator). On the rotor, the winding is designed to create an electromagnetic field, without which it is impossible to get movement. Around the rotor, one magnetic field is created, and around the stator, a field that opposes it. It turns out that one pushes the other and sets the engine rotor in motion. If you describe it in simple and accessible language.
On the stator, the winding is stationary; applying voltage to it is quite simple. But the rotor is a moving part, so you have to use a brush assembly. The supply voltage is fed through the brushes to the lamellas on the collector, and then to the rotor winding. The brush assembly is the most vulnerable part in the starter, as it is composed of copper and graphite. The material is such that it is quickly erased, so the brushes need to be replaced.
Bendix is an element that serves to transfer motion from the starter rotor to the flywheel. It consists of an overrunning clutch, gear and fork. The clutch allows the mechanism to rotate in one direction only. The plug connects the solenoid relay and the bendix itself. With its help, the gear with an overrunning clutch moves along the rotor. You can find two designs of starters. High-speed ones, in which a planetary gearbox is used, the motor rotor and the final shaft are not one-piece. And a simple design in which the shaft is one-piece from start to finish.
Starter Malfunction Symptoms
Malfunction often occurs when the starter motor turns and the flywheel does not move. At the same time, extraneous metal sounds, grinding are heard. This indicates that the flywheel crown is worn out and needs to be replaced. It is worth noting that when the crankshaft is scrolled a few centimeters, the starter “grabs” and the car starts up. For repairs, you will need to remove the gearbox and change the crown. As a last resort, you can simply turn it over, as it wears out to the middle.
But if the starter is spinning, but the movement is not transmitted, there are no extraneous sounds, and when the crankshaft is cranked, the engine does not start, then the problem is in the overrunning clutch. Remove the starter, disassemble it, check the clutch. If it rotates freely in both directions, replace it immediately. Usually, the clutch comes in a single design with a fork and gear.
But if you do not hear the click of the retractor relay, then you can judge that there are two breakdowns. The most harmless is a dead battery, so there is not enough current to attract the armature. If the battery is charged, then there is a malfunction in the retractor relay. Either the winding burned out, or the contacts burned out and stopped conducting electricity.
