A starter motor (also self-starter, cranking motor, or starter) is a part present on any modern automobile, its purpose being to help start the engine and provide electricity to the consumers. Also called the starter, the starter motor is composed of an electric motor and a solenoid.
Have you ever seen old footage of people starting their cars in the interwar period? For this they had to get out of the car, stand in front of it and turn a crank to start the engine. What a hassle!
Today’s engines aren’t that different from those days, at least when it comes to how they start. But instead of turning the crank, modern cars have a starter motor (small electric motor) that starts the engine when you turn the key in the ignition.
These starters also worked as generators once the engine was running, a concept that is now being revived in hybrid vehicles.
Here are some things you need to know about a car’s starter motor (motor controller, or electric motor starter).
The first electric starter was installed on an Arnold, an adaptation of the Benz Velo, built in 1896 in East Peckham, England, by electrical engineer H. J. Dowsing.
How the starter motor works
The starter motor is an electromechanical device that has the ability to convert electrical energy into mechanical energy. To do this, it uses electromagnetic waves.
When we put the key in the ignition and turn on the ignition, the starter motor is circulated by a very high electric current whose voltage is regulated to reach 12 volts.
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
Electric car specs
When DC power from the starting battery is applied to the solenoid, usually through a key-operated switch (the “ignition switch”), the solenoid engages a lever that pushes out the drive pinion on the starter driveshaft and meshes the pinion with the starter ring gear on the flywheel of the engine.
The solenoid also closes high-current contacts for the starter motor, which begins to turn. Once the engine starts, the key-operated switch is opened, a spring in the solenoid assembly pulls the pinion gear away from the ring gear, and the starter motor stops.
A solenoid is a type of electromagnet formed by a helical coil of wire whose length is substantially greater than its diameter, which generates a controlled magnetic field. The coil can produce a uniform magnetic field in a volume of space when an electric current is passed through it. The term solenoid was coined in 1823 by André-Marie Ampère.
A starter motor is made up of several elements, which act together, forming an assembly:
- Stator (it is the fixed component of a starter);
- Rotor (unlike the stator, it represents a moving part in the circuit of an electric motor, but together with it (with the stator), driven by an electric current, they produce an energy field that puts the motor into operation);
- Collector brushes (have a role in ensuring and transmitting the electric current to the two components above);
- Bushes (they are the elements that stabilize the starter);
- Clutch (helps to maintain a regular speed of the starter motor);
- Solenoid (it is also called the coil and is found on the walls of the cylinder, next to the rotor. It is the one that engages the electromagnetic circuit, being the component that puts the entire starter motor assembly into operation, from the moment the key turns in the ignition to start the car engine ).
Where is the starter motor?
The starter motor is attached to end of the crankshaft via a flywheel and a pinion gear. When the ignition is turned the starter motor activates and an electromagnet inside pushes a rod out with the pinion gear.
How do you check a starter?
Connect the remote starter switch to the battery positive and the solenoid (smaller wire) terminal on the starter and click the switch. If nothing happens, you’ve got a bad starter. If the starter turns, the problem is in the electrical system.
What gives power to the starter?
The car’s battery sends power to the starter to get the vehicle running. Car’s battery has three responsibilities: Powering the lights, radio, and other vehicle components when the engine is off.
During actual start-up of an engine, a starter will draw 250 to 350 amps. The typical starter for a gasoline 4-cylinder engine has a wattage rating between 1,000 and 1,200 watts.
Why doesn’t the engine start?
If when we turn the key in the ignition the engine does not start, it is a sign that there may be a problem at the level of the starter, either at the level of the solenoid or at the level of its motor.
Another cause could be an electrical issue with the starter motor or a dead battery. If the starter motor has completely gone there’s no way to get your car going again.
The dial reading should be 12 volts or more. Work the starter switch, and the reading should fall, but not below 10.5 volts. If the reading does not fall, there is a fault in the ignition-switch circuit or in the solenoid. The least volts you need to start your car is 11.8v.
For what reasons can the starter fail?
From the point of view of the type of car components, electric motors are part of that category that has a long life span, without requiring replacement after a certain period of time or after a limit of kilometers driven by the car.
Consumer Reports: New EVs have problems
In principle, a starter motor can work in perfect condition for several years. However, there are certain actions that drivers frequently commit erroneously, certain inappropriate behaviors or “unhealthy” habits that affect the existence of the electric motor and shorten its service life.
Here are the causes that can lead to the wear and/or failure of a starter motor:
- Power supply issues – When the supply and transmission of electrical current oscillates, and this happens frequently (either too much electrical energy load is being transmitted to the motor, or too little), the starter can go through various states, from to overheating and overloading, until it is under voltage.
It is essential to check the voltage in the battery terminals at a certain interval and, if you notice that there are difficulties in starting the engine, for these reasons, to fix the problem before it is too late.
- Excessive humidity – Condensation resulting from the too long interval between stopping the engine and restarting it can be quite harmful to the electric motor.
When the engine is warm, the water is evaporated, but when it is cold, the existing moisture can be a decisive factor in damaging the engine insulation and corroding it.
Car won’t start in the cold – possible causes
It would be ideal for any driver not to allow too much time to pass between turning off the engine and restarting it, obviously as much as possible to prevent condensation.
- Excessive heat – When the electric motor constantly overheats, it can cause the protection system, which surrounds the coil, to melt.
If the coil is no longer protected, a short circuit can occur more often, which is meant to damage the entire system of the electric motor. For this reason, you should make sure that this key component of any car is welcome so that overheating is avoided.