DC Motor For Electric Car

Electric cars can run on AC (alternating current) and DC (direct current) depending on the motor used to power them. In this article, we will look at the application of a DC motor for electric vehicles and what advantages and disadvantages it holds for EVs. 

A DC motor for an electric car will convert electrical energy into mechanical energy to power and run the car. Advantages of a DC motor include higher torque on starting, little to no transmission, and less heat production over an AC motor. 

AC and DC motors are used to build a fully functioning electric vehicle. Alternating current runs on a high voltage and is usually used to power these cars. Still, DC motors are cheaper and offer some obvious advantages over AC motors, like eliminating the need for an inverter, which is why most home-built electric cars run on DC motors. 

How Does A DC Motor Work? 

In summary, DC motors take direct current from a source and convert it to mechanical energy. The very first DC motor was developed in the 1830s-1840s, but its use was quite limited due to batteries being expensive. 

As years passed, the electrical grid was developed, and batteries became cheaper. However, other motors were also invented, which ultimately kept the DC motor and its use at bay. 

The rotor of a DC motor is located on the inside while the stator is on the outside. The rotor has coil windings powered by the DC. The stator comes with permanent magnets or electromagnetic windings. 

As the motor gets powered by the DC current, a resulting magnetic field gets created in the stator, which attracts and repels the magnets on the rotor. This causes rotation in the rotor. 

A commutator in the motor keeps the rotor rotating. When the rotator gets aligned with the magnetic field, it stops spinning. However, it reverses the current passing through the stator and the magnetic field. 

Four Types Of DC Motors 

Over the years, the traditional DC motors have evolved and become advanced. There are four main types of DC motors that we’re going to explore below: 

Brushless DC Motor 

The development of solid-state electronics made the invention of a brushless DC motor possible. These are also known as synchronous DC motors or commutated motors. The major difference between a brushless DC motor and other varieties is the absence of a commutator.

Instead, they have an electronic servo mechanic which detects and adjusts the rotator’s angle.

A brushless DC motor is more durable and suffers less wear and tear as compared to its brushed counterpart. This is because it has no commutator and its brushes. 

Brushed DC Motors 

This is the original design invented by Sprauge in the 1830s. This contains a traditional commutator that reverses the current every half cycle to produce a single-direction torque. 

Although these are still used for paper machines, cranes, electrical propulsion, and steel roller mills, they have been gradually replaced by safer and more durable brushless DC motors. 

Shunt DC Motors 

This is a variation of the brushed motor with field windings parallel to the armature. These parallel windings cause the motor to have a lower current. These are used in places where a constant torque is required with minimum alteration of load through speed, like conveyor belts, mixers, and hoists. 

Series DC Motors

The field windings are connected in a series and provide a high torque on starting, which is why this type of DC motor is often used in electric cars. 

DC motors are used in electric cars due to their reliability and efficiency. Kit car makers and hobbyists like to use these large DC motors when building their own electric vehicles. 

Advantages Of Using A DC Motor For Electric Cars

Being one of the oldest technologies has its advantages. Some obvious benefits come with a DC motor. Let’s explore these in a bit more detail: 

Speed Control 

Highly controllable speed is no problem with a DC motor. A simple change in the armature of the field voltage can allow you to control different speed variations. 

High Torque Levels

A DC motor offers high torque on starting and also consistent drive power. This makes it the perfect choice for electric vehicles and their extra mass. 

Easy Operation 

DC power is stable and can immediately start and stop as per the driver’s needs. It can directly deliver high torque and also stop immediately. This and the fact that it offers a wide range of controllable speeds make it the obvious choice for electric vehicles. 

No Harmonics 

A harmonic is a multiple of the fundamental frequency of any electrical system. These happen due to non-linear loads and are present in some AC motors. This causes power quality issues and pulsations that can reduce torque. DC motors don’t have harmonics-related issues. 

Frequently Asked Questions

1. How Many Batteries Does An EV Have? 

There are two batteries in an electric vehicle, each serving its own purpose. Like traditional vehicles, EVs also have a 12-Volt lead-acid battery which helps start the vehicle and power some of the electrical accessories and functions. 

2. Can Fast Charging Damage An Electric Vehicle In The Long Run?

Fast charging can reduce the lifespan of your EV’s battery and do more harm than good in the long run. 

3. Can A DC Fast Charger Be Installed in Homes? 

A DC fast charger cannot be installed in a house because it is specifically designed to be installed in commercial and industrial areas. You can quickly locate a public DC charger in places like parking spots, malls, and near highways. These will typically cost you $0.04 to $0.06 per kW. 

Final Thoughts

DC motors are not widely used when it comes to electric vehicles. However, they offer a good alternative for manufacturers to add them to their future models. They are cheaper and sometimes even more reliable than AC motors.

Best of all, they don’t require an inverter with the car battery. Check out the details of the advantages a DC motor can offer to an electric vehicle.