EV Motors: Behind The Scenes

Electric cars offer a more environmentally friendly option for our modes of travel. Ev’s may seem new but they have been around since the 1830’s. This predates gas powered vehicles. Fast forward to today ev’s have evolved to compete with gas powered vehicles offering all the creature comforts of any internal combustion engine (ICE) and more. However, there are certain conveniences EV’s haven’t been able to win over the ICE.

You may hear the biggest complaint from car enthusiasts is the sound. What sound ? Exactly. But there are other attributes of fun, luxury and convenience that the EV nails. You’ve probably seen videos of electric cars embarrassing the best sports cars in racing, showing off what electric power can do. You might have seen your favorite car get embarrassed by an electric car and you might be wondering, how? This is why we’re here.

What you will learn about:

EV motor :

How do EV motors work ?

An EV motor is what an electric car uses to harness the electric power from the vehicle’s battery pack. At first glance it may look or seem complicated but they all work by basic principles we can all understand. The basic principles of an electrical circuit and the basic principles of a magnet. At some point both will be combined to form an electromagnet, but first let’s explain the basics of an electrical circuit.

Electrical circuit

An electrical circuit is a flow of electrical current from a power source such as a battery, through electrical wires to a unit that can harness that electrical power like a light bulb or motor etc. Let’s work with the light built for now. If you remove the battery, the current stops flowing. However, our little circuit has a switch. This is a point where the flow of current can be disconnected and connected instantly by the separation of the electrical wires. Simply put the switch is our on/off button. One important piece of information to note is that once the battery connects, the flow of current is in one particular direction. If you flip the battery, the flow of current changes to the opposite direction. Either way the light bulb will still remain lit once current is flowing.

Magnets

Magnets are metals that have the ability to attract other metals. A couple basic things to note about magnets are, they have two points on opposite ends called a “North Pole” and a “South Pole”. Another thing is that opposite poles attract each other and like poles repel. In a scenario where you have two magnets of rectangular shape, if you put both close enough together with like poles on the same side, it will push away from one another. Now if you were to stick a circular pin into the middle of one of the magnets, then align like poles again they would push from one another and the magnet on the pin would start to spin in a circular motion. As the magnets rotate to one side, if you keep putting the same poles together the rotation continues. This reactionary rotation of the magnet is the very basics of how EV motors work.

Electromagnet

Lets combine both basics of an electrical circuit and magnets so we can develop a deeper understanding of EV motors. In an electrical circuit you have the battery connected to a light bulb via electrical cords, with a switch installed for an easy way to disconnect the flow of electrical currents. Now let’s replace the light bulb with a metal bolt. A metal bolt is made up of magnetic domains pointing in different directions. This is the opposite of a magnet which has their domains pointed in a particular direction. However, in this electrical circuit the light bulb is replaced by the metal bolt. The bolt is then wrapped in electrical wires from one end to the next. The wire connected to the battery is connected at each end just like the light bulb was.

With everything being connected the flow of current forces the magnetic domains of the bolt in the same directional flow thus creating a magnet out of the bolt, hence electromagnet. Now the bolt has become an electromagnet, it has a north and south pole like a permanent magnet. The north and south pole will depend on the directional flow of the electrical current. For instance if you flip the battery the flow of current will change, thus changing the poles. The same thing will happen if you switch the wires with one another on each side of the bolt. This process is called changing the polarity of the magnet. Now if we put a circular pin in the middle of the bolt so it can rotate, then put two magnets on each side with north and south pole on opposite ends, it rotates because of the magnetic reaction.

With the north and south pole on each side of the electromagnet the reaction to the outer magnets should be, like sides repelling and opposite sides attracting. However, we will have to keep switching the connected wires of the bolts to each side in order to change its polarity. Once polarities line up we get the right reaction from the magnets to cause rotation. This is a deeper understanding of EV motor basics. The constant changing of polarity to inspire movement. Rotation in this instance. This doesn’t mean wires are being  constantly switched out. The design is a lot more sophisticated and efficient, harnessing more energy from this reaction. This example is based on a DC motor design, which stands for Direct Current motor. There are other types of motors like AC that work a little differently but all of them produce rotational motion. AC motors mean alternating current motors. An electric vehicle uses a mix of both, but mostly AC motors.

What motors are used in electric vehicles ?

The most common motors used in electric vehicles are AC motors. This is an alternating current motor which uses alternating currents like the term suggests. The basic concept is similar to that of a DC motor which is explained above. This version of motor also uses electromagnetism just like the DC motor except it uses the magnets’ electromagnetic fields to induce a rotor causing it to spin. A magnet has a magnetic field which causes the magnet to attract other metals and also repel like poles or attract opposite poles.

The same goes for an electromagnet. Just like in the DC motor it is wrapped in coils of copper to make it stronger. Once electricity is flowing through it, the electromagnetic field expands. Once alternating currents flow through, the field expands and contracts with the poles switching sides. Once the rotor is in close proximity the fields can induce the rotor inspiring movement which is the basics of an operating AC motor. The AC motor’s design allows the rotor to spin in a circular motion making useful mechanical energy.

What is the best ev motor ?

The best EV motors are AC motors. Hence the reason they are mostly used in electric vehicles. Induction AC motors to be exact. Even the famous Tesla EV cars use this. AC motors have a great balance of power and efficiency. They also don’t require as much maintenance. AC motors don’t need parts like brushes nor commutator rings, a permanent magnet or position sensors. Pieces like the commutator ring and brushes will experience wear and the position sensors are extra parts,which means more opportunity for things to go wrong.

Electric motors price ?

Ev motor prices can cost anywhere from 9k – 18k in parts and another $3,000 in batteries. Retrofitting can even cost up to 20k. Here is a list of manufacturers that make EV motors :

• Tesla
• Toyota
• Nidec Corporation
• UQM Technologies
• TVS Motor Company
• Xpeng
• ABB Ltd
• Robert Bosch
• Denso
• Brose Fahrzeugteile SE & Co. KG
• Johnson Electric Group

EV Controllers :

How is an EV motor controlled ?

An EV motor is controlled by what we call a controller or an inverter. This unit regulates the flow of electric current coming from the battery pack to the EV motor. It’s basically a really fast lightswitch turning current on and off in milliseconds thousands of times. That control gives it the ability to regulate how strong or weak the flow of current is in an EV motor.

Controllers used in EV Cars

Most EV cars use AC controllers due to the fact that they used AC motors. AC controllers convert DC Power from the battery pack to Alternating current for the AC motors. AC motors used alternating current which is what “AC” stands for.

What is a speed drive controller for electric motors ?

Speed drive controllers regulate the speed of an electric motor by regulating how much power flows into the motor. This also makes the motor more performance oriented, by having more control for specific applications.

Conclusion

Although an electric car doesn’t offer as much sound and excitement of a traditional internal combustion engine, it still offers a different type of fun. EV may be less engaging but the thrill of driving is something both EV’s and Gas engines do well. We don’t know what the future holds when it comes to vehicle travel but it for sure will still be an experience worth having.