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Electric cars are making big waves[br]in the automobile world.

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These noise-free, pollution-free[br]and high-performance vehicles

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are expected to make their IC engine[br]counterparts obsolete by 2025.

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This video will unveil the hidden [br]technologies behind the Tesla model S,

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which recently became the world's[br]fastest accelerating car.

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We will see how electric cars have[br]achieved superior performance

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by analyzing the technology [br]behind the induction motor,

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inverter,

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lithium-ion battery power source,

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and, above all, the synchronized[br]vehicle mechanism,

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in a logical step-by-step manner.

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The powerhouse of the Tesla[br]car is an invention

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made by the great scientist Nikola Tesla[br]around 100 years back:

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the induction motor.

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The induction motor has two main parts:

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the stator and the rotor.

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You can see the construction[br]details of the motor here.

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The rotor is simply a collection of conducting[br]bars short-circuited by end rings.

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A three-phase AC power input[br]is given to the stator.

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The three-phase alternating current in[br]the coils produces a rotating magnetic field.

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The Tesla motor produces [br]a four-pole magnetic field.

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This rotating magnetic field that induces[br]current on the rotor bars to make it turn.

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In an induction motor, [br]the rotor always lags behind the RMF.

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An induction motor has neither [br]brushes nor a permanent magnet.

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At the same time it is robust and powerful.

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The beauty of an induction motor is that

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its speed depends on [br]the frequency of the AC power supply.

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So just by varying the frequency[br]of the power supply,

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we will be able to alter [br]the drive wheel speed.

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This simple fact makes electric car [br]speed control easy and reliable.

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The motor supply is from [br]a variable frequency drive,

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which in turn controls motor speed.

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The motor speed can range[br]from 0 to 18,000 rpm.

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This is the most sizable[br]advantage electric cars have

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when compared to internal combustion cars.

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An internal combustion engine[br]produces usable torque

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and power output only [br]within limited speed range.

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Therefore,

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directly connecting the engine rotation[br]to the drive wheel is not a clever idea.

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A transmission must be introduced[br]to vary the drive wheel speed.

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On the other hand, an induction motor[br]will work efficiently in any speed range.

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Thus, no speed varying transmission[br]is needed for an electric car.

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Moreover, an IC engine does not[br]produce direct rotational motion.

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The linear motion of the piston has [br]to be converted to rotational motion.

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This causes major problems [br]for mechanical balancing.

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Not only is the internal combustion engine[br]not self-started like an induction motor.

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Further, the power output of[br]an IC engine is always uneven.

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Many accessories are needed[br]to solve these issues.

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On the other hand, you will[br]have direct rotational motion

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and uniform power output [br]with an induction motor.

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Many components in the IC engine[br]can be avoided here.

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As a result of these factors,

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a great response rate and[br]higher power to weight ratio

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comes naturally to an induction motor[br]resulting in superior vehicle performance.

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But from where does [br]the motor receive power?

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It's from a battery pack.

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The battery produces DC power.

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So before supply get to a motor [br]it has to be converted to AC.

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An inverter is used for this purpose.

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This power electronic device also[br]controls the AC power frequency,

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thus controlling the motor speed.

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Moreover, the inverter can even[br]vary the amplitude of the AC power

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which in turn will control [br]the motor power output.

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Thus, the inverter acts as [br]the brain of the electric car.

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Now, let's turn our focus [br]to the battery pack.

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You will be amazed to find

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that they are just a collection[br]of common lithium-ion cells

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similar to those used in your daily life.

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The cells are connected in a combination[br]of series and parallel

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to produce the power required [br]to run your electric car.

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Glycol coolant is passed [br]through metallic inner tubes

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through the gap between the cells.

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This is one principal innovation of Tesla.

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By using many small cells[br]instead of a few big cells

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effective cooling is guaranteed.

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This minimizes thermal hot spots and[br]even temperature distribution is achieved

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leading to higher battery pack life.

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The cells are arranged [br]as detachable modules.

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There are 16 such modules in the battery[br]pack constituting around 7,000 cells.

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The heated Glycol is cooled down[br]by passing through a radiator,

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which is fitted at[br]the front of the vehicle.

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Moreover, you can see how[br]such a low height battery pack,

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when fitted close to the ground level,[br]will lower the vehicle center of gravity.

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The lower of gravity improves[br]the stability of the car considerably.

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The large battery pack is[br]also spread across the floor

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offering structural rigidity [br]against side collisions.

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Now let's get back to Tesla's drive-train.

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The power produced by the motor is[br]transferred to the drive wheels via a gearbox.

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As previously discussed, Tesla Model S[br]uses a simple single speed transmission

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because the motor is efficient in [br]a wide range of operating conditions.

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You can see that output speed from [br]the motor is reduced in two steps.

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Even achieving the reverse gear[br]is quite easy in an electric car.

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Just change the order of[br]the power phase for this.

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The only purpose of electric[br]car transmission

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is speed reduction and[br]associated torque multiplication.

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The second component in [br]the gearbox is a differential.

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The reduced speed drive is passed to it.

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You can see this is [br]a simple open differential.

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However, open differentials, [br]have a problem of traction control.

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But, why does such an advanced[br]car use an open differential

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rather than a limited slip differential?

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The answer is that the open differential[br]is more rugged and can carry more torque.

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The traction control problem that[br]occurs in an open differential

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can effectively be overcome [br]with help of two methods:

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selective braking

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and cutting the power supply.

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In an internal combustion engine,

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this power supply cut by cutting[br]the fuel is not so responsive.

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In an induction motor, however,[br]the power supply cut is quite responsive

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and an effective means for[br]obtaining traction control.

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In the Tesla,

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this can all be accomplished using[br]a state-of-the-art algorithm

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with help from Sensors and controllers.

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In short, Tesla Motors has replaced [br]a complex mechanical hardware system

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with smart responsive software.

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Did you know an electric car[br]could be driven efficiently

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with the help of just one pedal?

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This is due to its powerful [br]regenerative braking system.

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That means saving the huge[br]kinetic energy of the car

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in the form of electricity [br]without wasting it as heat.

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In an electric car, as soon as[br]you release the accelerator pedal,

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the regenerative braking [br]comes into action.

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The interesting thing is that,[br]during the regenerative braking

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the same induction motor [br]acts as a generator.

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Here the wheels drive the rotor[br]of the induction motor.

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We know in an induction motor [br]the rotor speed is less than the RMF speed.

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To convert the motor to a generator,

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you just have to make sure that the rotor[br]speed is greater than the RMF speed.

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The inverter plays a crucial role here[br]in adjusting the input power frequency

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and keeping the RMF speed[br]below the rotor speed.

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This will generate electricity[br]in the stator coils,

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which is way higher than [br]the supplied electricity.

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The generated electricity [br]can then be stored

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in the battery pack after the conversion.

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An opposing electromagnetic force acts[br]on the rotor during this process,

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so the drive wheels and [br]the car will slow down.

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This way vehicle speed can [br]be accurately controlled

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during the drive using a single pedal.

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The brake pedal can be applied [br]for a complete stop.

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As you might already be aware,

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electric cars are much safer [br]than internal combustion cars.

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The cost of maintaining and[br]driving an electric car

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is much lower than that [br]of an IC engine car.

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With the drawbacks of the electric car evaded

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through the advent of improved technology,

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electric cars promise to [br]be the cars of the future.

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We thank Mr. Jehu Garcia,

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an electric car expert and YouTuber[br]for his technical support for this video.

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Your support at patreon.com [br]is highly appreciated.

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It enables us to make additional [br]free educational videos for you.

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Thank you.