Why Does a Tesla Car Use an AC Motor Instead of a DC One?

Electric car companies like Tesla are heading to use AC motors instead of DC ones for many reasons; however, the DC motors were the first motors type to be used in electric cars. Over time the DC motors proved that they are not ideal for electric cars and must be replaced.

Why Does a Tesla Car Use an AC Motor Instead of a DC One?

Tesla car uses AC motor instead of dc one for many reasons; the AC motors don’t have permanent magnets or field windings, and they don’t have commutators or brushes that can wear out. The AC motors are highly effective than the DC ones; however, the AC motors were used later after DC motors.

The AC motors were used in cars after the DC motors failed to prove themselves; the main reason why AC motors were not used first is that it was complicated to convert batteries DC to AC to supply the motor. The dynamo was the first step in using AC motors in cars.

Why is AC Motor Preferred Over DC Motor?

Electric cars like Tesla cars use AC motors instead of DC motors to power their wheels; the central concept of AC motors is that they rely on generating a changing magnetic field. The motor consists of a rotating coil known as a stator; the stator is responsible for generating the current-carrying magnetic field.

The magnetic field interacts with the rotor, a magnetized piece of metal; due to this interaction, the rotor rotates at high speed. The final result is rotational kinetic energy which is transferred into torque on the output shaft; the following reasons clarify more:

1). The Generative Feature of AC Motor

AC motors are similar to generators; both generators and AC motors are regenerative, so they can take in energy and regenerate it. Absorbing and returning the energy is done by reversing the current’s direction passing through the coil, where the rotor changes into a stator.

The rotor is a magnetized component made from metal that generates a magnetic field from rotating at high speed. The magnetic field generated induces a current in the other rotating wire. The AC motor is characterized by a significant feature called regenerative, where the motor acts as a generator and charges itself while you are driving.

This feature draws back the power to the car’s battery, so the cycle continues; the electricity goes for the car to move and then comes back to the battery to charge the car. Therefore, the main benefit of the regenerative feature is that the motion energy is converted into electricity, and electricity is converted into motion energy.

As a result, your vehicle’s battery will be drained less than regular cars, as the AC motor charges it while driving. The DC motor can also be used for the same purpose but with less efficiency than the AC motor; the motor will require modifications, making the process complex and costly.

 2). Better Grip in Rough Terrians

One feature that gives the AC motor another advantage is that they are suitable for rough terrains. The advantage of the AC motor comes from the high speed and the torque of the AC motor, making it more adapted to these rough conditions, offering you a better grip on your vehicle.

The AC motor is characterized by high output power; therefore, the high output power overcomes the resistance experienced in the tires in such rough areas. The output power of the vehicle is vital as it determines the wheel rotation; the rotation of wheels should always be higher than the resistance experienced; otherwise, the vehicle will face challenges whenever it passes by rough terrains.

When comparing the AC motor output power with the DC motor output power, you will find that the AC surpasses by a significant difference. This is because the AC motor generates more torque than the DC one, making electric cars like Tesla more potent than regular cars. In addition, the AC motor is weightless than the DC one, which gives another advantage to electric cars; decreasing their weight.

3). High Power Output

Electric cars demand high power, and the AC motor is characterized by high power output which fulfills the demands of electric cars and makes it suitable for them. In addition, the power output generated from AC motors in electric cars like Tesla determines their breaking speed and acceleration.

This can be noticed if you try a vehicle with enhanced power output; the car’s response when you press the acceleration pedal is faster. As a result, the car becomes more efficient and senses every touch of the acceleration pedal. AC motors have a frequency that determines the number of rotations in the motors; the higher the rotations, the higher the vehicle’s speed.

4). Long Lifespan

The vehicle’s lifespan is a crucial aspect you should consider when buying it because you must ensure that your investment is worth it. An excellent example of a good investment is that your car doesn’t need mechanical repairs in the first few years after buying it.

In electric cars, if there is any mechanical failure or problems in the AC motor, you can easily replace it with a new one. In addition, you will not need to replace any control units or batteries; this makes the electric cars have a long lifespan and an excellent choice to invest in.

Since electric cars use AC motors, they don’t face any twisted shafts, broken gear teeth, or damaged joints; they don’t have brushes or commuters like DC motors. However, the mentioned parts require regular maintenance, which can affect the life span of your motor if you ignore them.

Regular check-ups and maintenance will cost a lot and can be very irritating if you don’t have time or a budget. AC motors miss many of these parts and components, requiring minimal check-ups and maintenance; they are also highly rigged.

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5). Electric Cars Demand High Specifications

Electric cars require a significant torque to obtain their high speeds, which makes the AC motor a perfect fit for electric cars as they are suitable for high torque and quick acceleration. The torque is used to power the vehicle wheels, making them go faster because it’s the generated rotational energy.

The main reason why the AC motors surpass the DC motor is that they are devoid of brushes, as the brushes affect the torque speed. The brushes are found in DC motors; they generate resistance force when the rotor spins, generating a magnetic field. The magnetic field creates a current in the stator that causes a commutation.

Therefore, the power and the torque are reduced by a significant degree due to the effect of the brushes, and brushes also can be damaged at high RPMs. This makes AC motors suitable for electric cars as they can offer high speed without damage. However, if the vehicle has a low torque and will need to be pushed until it starts, electric cars can’t have this solution as they require minimal pushing.

The AC motors provide the electric cars with the required torque, so they don’t need to be pushed; the high torque of AC motors also benefits the electric cars by providing quick speed changes. In addition, AC motors can have high torque at low speeds so that cars will have a high acceleration; the desired speed change can be achieved in the desired time.

6). Safe on The Environment 

AC motors give electric cars an advantage over gasoline cars; the AC motors work by the power of electricity and magnetic fields, so they do not produce any emissions that can pollute the environment. Companies that aim not to pollute the environment can benefit from this feature in AC motors. 

AC motors’ efficiency is very high compared to the best DC motors; the AC motors have an efficiency of 94%; meanwhile, the best DC motors have an efficiency of 75%. The efficiency means that the motor doesn’t waste any converted energy; the AC motors surpass 94% efficiency. 

7). No Noise Polluiton

Electric cars are unlike gasoline cars; they don’t create as much noise as gasoline cars when moving. The reason for the less noise pollution of electric cars lies in the AC motors, which are much quieter than DC motors and produce fewer vibrations. Therefore, when you see an electric car passing by, you may not be able to hear its motor sound, the only sound you can hear is its tire sound.

8). AC Motors Can Be Programmed

A fantastic feature of AC motors is that they can be programmed, and you can set the suitable driving style for you. This process is controlled by designing the AC inverter where each style has a special AC inverter, and you can set the parameters according to your choice.

For example, if you want to increase the vehicle’s range, you can set the regen to maximum and the voltage of the battery to a minimum for driving. Unfortunately, this feature is not available in gasoline cars; the electric cars in the future will surpass the gasoline ones by a significant difference making the gasoline ones not ideal for use. 

9). Increased Safety

Safety is a critical aspect that companies always look after in electric cars, especially those that use lithium-based batteries. The AC motors ensure that the electric cars don’t overheat, which was a problem with lithium-based batteries. Solving the overheating problem decreases the costs of installing cooling systems. 

AC motors have many benefits economically, environmentally, and safely; electric cars have gotten rid of flywheels and batteries as they generate electricity consistently; therefore, there is no need for them to store energy.

The voltage of the AC motor can be controlled, where it’s turned off and on per the speed needed to generate the energy from it. As a result, the AC motor is safer for electric cars as it doesn’t produce much heat. In addition, the AC motor presence clears the chance of batteries exploding in case of an accident. 

Conclusion

Electric car companies like Tesla use AC motors instead of DC motors for many reasons. For example, AC motors don’t have permanent magnets or field windings, and they don’t have commutators or brushes that can wear out. In addition, the AC motor has higher efficiency in converting energy than DC motors. 

AC motors have an efficiency of 94%; meanwhile, the best DC motors have an efficiency of 75%; in addition, AC motors have a longer lifespan and need minimal maintenance, which makes electric cars an excellent investment.

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