The electric motor in cars explained

This article seeks to discuss electric motors for everyday car owners. We will discuss what an electric motor is, its functions, where the electric motor is found in an automobile, what can make the motor get bad, how to fix it, and some maintenance tips.

Electric motor overview

Electric motor

It is a very vital component of an automobile. Without the electric motor, the transmission will not take place. An electric motor is a component in a car that transmits electronic power to mechanisms like the key starter and wiper to function appropriately.

An electric motor is an electric device that converts electrical energy to mechanical energy. It operates in contact with the vehicle’s magnetic field on the winding current, producing a torque-shaped force applied to the motor shaft. You’ll find electric car motor in key starters and wipers.

The key starter transmits power to the flywheel to enable the engine to start. And the wiper also has an electronic motor that sends power for the wiping mechanism to occur.  Here, have a read of our previous article to know more about the flywheel. Furthermore, all-electric vehicles have an electric motor instead of an internal combustion engine.

How does the electric motor work?

How does the electric motor work

The motor is linked directly to an energy source, and its rotation speed depends entirely on the strength of the electric current. When power comes into the unit and transmission arises within that axis, a rotational force transmits the power to other components.

The power of an electric motor increases as its speed increases. Electric motors function on the principles of electromagnetism and electromagnetic induction. When an electric current is passed through a conductor wound around an iron rod, the magnetic field expands and focuses on the ends of the iron rod.

An electric motor is a series of iron bar electromagnets arranged in a circle with both ends facing the center. A loop of wire is attached to the shaft between them, and one side of the loop is placed near one electromagnet. The other side of the loop is on the other side of the electromagnet.

Similar magnetic field poles face each other when an electric current flows through the loop and the electromagnet. Then, the magnetic field is pressed against the coil of the wire. Torque is generated on the shaft, and it revolves within the circle of the electromagnet. This torque is what causes rotation.

Parts of an electric motor

Parts of an electric motor

The electric motor comprises of:

  • The Armature: The armature is a rotational field with a magnetic force. It works with friction while rotating with the brush on it.
  • The Brush: The brush is attached to the armature. It works on the armature as it rotates.
  • The magnetic field: Without the magnetic field, the armature cannot transmit power.
  • The dry shaft: The dry shaft transmits power from the fiber polymer on the surface of the electric motor for the rotational force to take place.

The function of the electric motor in cars

  • To transmit revolutionary force to mechanical components.
  • It converts electrical energy to mechanical energy.

What can cause the electric motor to go bad?

bad electric motor
  • Constant rotation

The electric motor is meant to rotate but return to be regulated for 3 to 5 minutes before it starts functioning again. Take, for instance, the motor in the key starter. Once you kick your car, the key starter returns from the flywheel, and rotation will no longer occur. If you continue kicking your vehicle, it will shut down.

  • When the brush gets bad

The brush works on the armature. As the armature rotates with the brush on it, the more the armature revolves, the more the brush reduces in size. There must be friction for the armature to function. When friction act on the brush, with time, its size reduces. At a certain point, the brush won’t touch the armature. This lack of contact will cause the armature to shut down.

  • Excess friction on the Armature

If there is extra friction, the armature breaches. When it breaches, it will burn, and the electric motor will shut down.

  • Winding failure

Electrical failure is a kind of winding failure caused by contactor opening, poor connections, blown fuses, or excessive heat. Electrical overload or broken power lines can also cause it.

  • Pollution

Grease, oil, and dirt are common pollutants that can enter electric motors. Moisture is also a harmful pollutant to motors. It can result in corrosion and cause the parts of the motor to malfunction.

  • Inadequate lubrication

You should lubricate the electric motor adequately because excessive lubrication or inadequate lubrication can cause damage to the motor.

  • Electrical overload

This is when the current flowing within the motor winding is excess and exceeds the standard capacity the motor can carry efficiently and safely.

  • Overheating

This can result from bad power quality or an environment with very high temperatures.

How to solve electric motor problems

How to solve electric motor problems
  • The brush often spoils in this motor. Once the brush is malfunctioning, lose out the motor. Screw out the 8mm bolts around the brush and pull it out. Then replace the brush.
  • For faults relating to the armature or magnetic field, replace the motor. You cannot fix defects like this.
  • You can install a practical current protection device. It is a device that can detect high currents and interrupt the supply to avoid electrical overload.
  • You can prevent overheating by keeping the motor cool and in an environment with a cool temperature.
  • Ensure that you lubricate the motor often to avoid it from getting faulty.
  • Ensure that you keep moisture away from the motor to avoid corrosion.

Where does the electric motor sit in an Automobile?

Electric motor in an automobile
  • The key starter motor is in between the gearbox and the engine at the key starter unit. See more about the gearbox.
  • Wiper: The wiper has two motors. It sits outside the dashboard by the windscreen in front. The first motor controls the wiping mechanism. The second motor transmits coolant fluid or water to the windshield.
  • There is an electric motor which we can also call an alternator. The alternator generates a current. The standard volt of a vehicle is 12volts. When your car comes on, the alternator generates more energy up to 13 or 14 volts to enable the machine to function very well.

You can also find electric motors in door locks, door windows, radiator fans, fuel pumps, intercooler fans, and CD players. Furthermore, electric motors are present in antennas, popup headlights, steerable fog lights, power steering, air conditioners, and sunroofs.

Can I fix a faulty electric motor by myself?

No, unless you have gone through technical training. An expert or technician should fix it.

Can a mechanical issue in my vehicle damage my electric motor?

When a mechanical component gets stuck and cannot rotate, the motor forces it to rotate. When there is a high resistance from the mechanical component, it causes the motor to blow up.

Difference between an engine and an electric motor

The two words come into play interchangeably. Therefore, we must distinguish them from the beginning. Today almost synonymously used in the automobile industry.

A motor is a device that converts energy to mechanical energy (and therefore movement), while an engine is very similar but mainly uses thermal energy.

Therefore, when we talk of thermal energy conversion to mechanical energy, we mean combustion, not electricity. In other words, the engine is a kind of motor. However, the motor is not necessarily the engine. In an electric vehicle, electricity generates mechanical energy, so the term “motor” refers to the device that powers the electric vehicle.

Importance of the electric motor in a car

  • They are perfect for speed regulation.
  • Electric motors have an efficient energy conversion capacity exceeding 95% conversion rate.
  • They are also suitable for braking action.
  • It serves you to maintain a large engine; you can easily use one small motor per wheel.
  • They make use of electronic controls rather than mechanical pedal or lever.

Conclusion and final words from the expert

Please take note of the electric motor as it is a very vital component. For automatic vehicles, once the motor is faulty, there is no manual way to start the vehicle.

For manual vehicles, when the motor shuts down, you can push start the vehicle. Once you discover that when starting your car and it doesn’t give a fast speed showing that rotation is taking place, check your electric motor. It is a sign that the motor is getting bad. At this point, you should fit your motor because anything beyond this will cause the motor to shut down completely.

Also for the wiper, it should give the three maximum speed which is slow, low and high speed. When it doesn’t give these three maximum speeds and is sluggish when moving, you need to inspect the motor. This inspection is to ensure the motor does not get damaged. In future articles, we would out the difference between an AC and DC electric motor.

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