What Are The Main Difference Between AC and DC Motors

What Are The Main Difference Between AC and DC Motors

There are two types of electric motors: AC and DC. AC motors are more common, while DC motors are used in more specialized applications. In this blog post, we will focus on the main differences between AC and DC motors, in order to help you choose the right electric motor for your needs.

What Is an AC Motor?

AC (alternating current) motors are powered by alternating currents, which periodically change direction. This type of electricity is generated by power plants and transmitted through the electrical grid. AC motors are more common because they are more efficient than DC motors and can be used to power a wide range of devices.

History of AC Motors | Who Invented The First AC Motor?

AC motors were invented by Nikola Tesla between 1883 and 1888 while he was working with Thomas Edison’s company. Around this same time period, Galileo Ferraris built a primitive AC motor while experimenting on his own without any direct collaboration with Tesla. It wasn’t until the mid-1890s that George Westinghouse, an entrepreneur, and rival of Edison, began to popularize AC power by building a large-scale AC transmission grid.

Different Types Of AC Motors

There are three main types of AC motors:

(i) Induction AC Motor

(ii) Synchronous AC Motor

(iii) Asynchronous AC Motor

Induction AC Motor

Induction motors are the most common type of AC motor. They are simple to construct, operate and can be used in a wide range of applications. Induction motors are typically three-phase motors, which means they have three coils that generate rotating magnetic fields.

Synchronous AC Motor

Synchronous motors are more efficient than induction motors and are often used in industrial applications. They are also more expensive to purchase and maintain. Synchronous motors use DC power to create a rotating magnetic field, which allows them to run at a precise speed.

Asynchronous AC Motor

Asynchronous motors are the least efficient type of AC motor. However, they are the cheapest to purchase and maintain. Asynchronous motors are powered by AC power, but their speed varies depending on the load.

What Is a DC Motor?

DC (direct current) motors are powered by direct currents, which flow in one direction. This type of electricity is generated by batteries and other small-scale electrical systems. DC motors are used in applications where high power or efficiency is important, such as electric vehicles and aircraft engines.

History of DC Motors | Who Invented the First DC Electric Motor?

DC motors were first developed in the early 1800s by Michael Faraday. Faraday was trying to find a way to convert electrical energy into mechanical energy and discovered that DC currents could do this more efficiently than AC currents. However, the development of AC motors eventually overshadowed DC motors due to their greater efficiency and a wider range of applications.

Different Types Of DC Motors

There are two types of DC motors. These are:

(i) Brushed DC Motor

(ii) Brushless DC Electric Motor

Brushed DC Motor

Brushed DC motors are the first types of DC motors available. In the brushed DC motor, the commutator and brushes are used to provide current flow in different directions so that it is possible for the rotor to rotate continuously in a single direction.

Brushed motors are constructed with a permanent magnet rotor and a field coil that surrounds the rotor. When DC voltage is applied to the field coil, it creates a magnetic field that interacts with the permanent magnets on the rotor. This interaction causes the rotor to rotate.

The commutator and brushes are used to provide current flow in different directions so that it is possible for the rotor to rotate continuously in a single direction.

Brushes wear out over time and need to be replaced periodically. Also, as the brushes wear they can cause electrical arcing which can damage the commutator.

Brushless DC Motor

The brushless motor does not use any mechanical contact with brushes or commutators. Brushless motor types include using hall sensors, back-EMF, and encoders in order to position and drive the motor. The brushless DC Electric Motors (BLDC / BRUSHLESS MOTORS) produce less noise, higher efficiency due to less friction and long life when compared with brushed DC electric motors.

Brushless DC Electric Motors is also termed as BLDC motors. In BLDC type motors there are three windings, one for each phase and these windings do not have brushes attached to them.

In a brushless DC electric motor, there is no need for any mechanical contact because all the power required by the system gets from the electronic circuit or controller, so here there is no wear & tear problem so the lifetime of the motor is very long. Another advantage of Brushless DC electric motors is that it produces an inherently balanced rotating field because the three phases must be 120 degrees apart from each other and there is no sparking between brushes and slip rings.

Difference Between AC and DC Motors: Advantages and Disadvantages

The main advantage of AC motors is that they are more efficient than DC motors. AC motors can convert more of the electrical energy into mechanical energy, which means they require less power to operate. This makes them ideal devices that need to draw a lot of electrical power, such as household appliances.

DC motors are simpler than AC motors because they don’t require the use of electrical rotors or stators to function. They also tend to be more rugged, which makes them useful in situations where safety is important. DC motors are often used in aircraft and electric vehicles because their lack of rotating parts makes them safe to use around extreme heat or flames that could start due to an oil or grease leak.

Advantages of AC Motors

  • More efficient than DC motors
  • Can be used to power a wide range of devices
  • Simple design
  • Low cost

Disadvantages of AC Motors

  • Require a reliable power grid to operate
  • Can be susceptible to voltage fluctuations
  • Produce more noise than DC motors

Advantages of DC Motors

  • More efficient than AC motors in certain applications
  • Rugged and reliable
  • Can be used in hazardous environments

Disadvantages of DC Motors

  • More expensive than AC motors
  • Require a battery or other electrical source to operate
  • Produce less noise than AC motors

How Does AC Motors Work?

Ac motors have two basic parts: a rotating part that turns the shaft, and stationary windings called stators around it. The stators are made up of coils of wires with electricity running through them. When alternating currents are applied to the coils, they generate magnetic fields around them. These magnetic fields interact with each other to create a force on the coils which pushes them out of alignment with the field, causing them to rotate. This repositioning of coils is known as excitation, while their rotation is called armature reaction.

A piston-like device called a rotor is attached to the motor’s shaft. The rotor, which has permanent magnets on one side and coils of wire on the other, spins around inside the stator coils.

The magnetic field from the stator causes the rotating rotor to turn as well. This happens because alternating currents create a constantly changing magnetic field that pulls at a wire’s electrons in a particular direction. If those changes are synchronized with the movement of a conductor through that magnetic field, it creates an electromagnetic torque that sets up rotation in much the same way as if you pushed someone across a room by alternately pulling them back and forth with your own arms. Instead of pushing them forward or backward, however, our example pushes them sideways from where they are standing, causing them to rotate.

Because they can create a rotating force on their own, ac motors don’t need any bulky external gear systems or transmissions between the electricity source and power delivery point as dc motors do. As a result, they’re lighter weight and more compact than other types of electric motors. In industrial applications they also offer benefits similar to those of dc motors: since their electrical currents are reversible, ac drives can start from rest with no additional parts needed. This helps increase equipment life expectancy by reducing wear from starts and stops. Unlike most forms of induction motor, however, ac induction motors can be started at very low rpm without a lot of noise and vibration due to the rotor’s permanent magnets being stationary when it is not turning.

How Does DC Motors Work?

DC motors are mainly used for small, low-power applications. They were predominant in older cars to control the speed and direction of the vehicle because they are relatively simple devices with low cost. DC motors have two main parts: a stationary stator containing coils of wire rigged across multiple poles, called slots, and an armature containing coils wound around a cylindrical core that rotates inside it.

When current passes through these windings, it creates electromagnetic fields around them. The rotating part is connected to the drive shaft by some mechanical device that turns this rotation into movement or vice versa. This movement applies force to the magnetic field surrounding the armature windings which causes them to reposition themselves as needed and produce a torque on their axis (just like our example motor above). The force applied to the armature is simple due to its cylindrical construction. Because of this, DC motors are often used in robotic projects which require a lot of torque and motion control. In fact, DC motors can even produce fast enough speeds to work as generators for powering external devices.

What Makes a Motor “Universal”?

The universal motor is an induction-type AC electric motor with a wound rotor and a squirrel cage design. It requires no field windings on the stator making it very popular for robotics because it does not produce much heat when turned at high speeds or under load. This means that they are also well suited to use in environments where there might be hazardous dust or corrosive gasses/chemicals present since the windings will not be damaged. Additionally, the universal motor can be started and run in either direction by reversing the polarity of the applied voltage.

Some disadvantages to using a universal motor include the fact that they are not as efficient as other types of motors and they require more maintenance because of the brushes and commutator. Additionally, they are not as reliable at high speeds or under load, so they are not typically used for industrial applications.

While all-electric motors use magnets to create movement, there is a wide variety of different motors available on the market today. Each type has its own unique benefits and drawbacks which may make it better suited for certain applications than others. By understanding how each type works, you can make a more informed decision next time you need to purchase or assemble your own motors for your project.

Which Motor Is More Powerful: AC or DC?

Typically, AC motors are more powerful than DC motors because they use an iron core in the rotor that helps to increase the torque by creating a larger magnetic field. However, DC motors can be designed to produce sufficient power output for certain applications, but the maximum RPM will usually be lower than 1/3 of what you would find with an equivalent AC motor.

What Kinds of Motors Are Used in Robots?

Almost all robots use some form of electric motor or actuator to provide movement and control functions. The two main types include servo/stepper motors and brushed DC motors. Stepper motors are used primarily in precision applications where very accurate movements are required even when dealing with resistance from difficult loads like gravity or other external forces. Brushed DC motors are much more common in consumer and industrial applications because they tend to be larger, stronger, and cheaper than their servo or steper counterparts.

Which Type of Motor Is Most Efficient?

Brushless DC electric motors are one of the most efficient types of motors available today because there is less friction between the various moving parts due to no mechanical contact between brushes or commutators during operation. The only downside with BLDC type motors is that they require a special controller because it requires H-bridges to operate which creates cogging torque at start up. However, that issue has largely been resolved by using advanced microprocessor-based controllers which overcome that problem without creating other issues like noise or interference with an external control system.

Frequently Asked Questions

AC or DC Motor for Ceiling Fan?

If you are having a room with less power supply then it is better to go for a ceiling fan that can work on a DC motor rather than AC Motor. Because in case of an AC motor the time taken for completing one revolution becomes a little more because during starting & stopping phase of its life, it requires 3 phase power supply but in the case of a DC fan you just need a single wire, so here time will not increase.

Do electric motors run on AC or DC?

Both of them will work on AC, but there are certain electric motors that can also work on DC.

Does Tesla use DC or AC motors?

Tesla uses AC motors.

Can a DC motor be used on AC power?

Yes, it can be done if there is an inversion unit.

What does AC & DC stand for?

AC stands for Alternating Current and DC stands for Direct Current.

Is a magnet powered by AC or DC?

It is powered by an alternating current because the magnetic field of the permanent magnets is reversed at regular intervals due to which the magnet gets its energy supply from electric alterations. This means that the direction of the current changes constantly and hence it’s called Alternating Current (AC). But there are certain applications where direct currents are also required, so instead of changing the magnetic field, one tube with permanent magnets is kept so that they have a similar effect as bar magnets, adjacent to each other. So in this case, it would be called Direct Current (DC) motor.

What is the difference between AC and DC motors?

The main difference between an AC and a DC motor is that an AC motor requires an induction coil to generate rotations, while a DC motor uses permanent magnets. Additionally, an AC motor usually has more starting torque than a DC motor. Finally, an AC motor will run at any voltage, while a DC motor must have a constant voltage supplied in order to function.

Is it better to use a DC or AC motor?

There is no definitive answer as to whether one type of motor is better than the other. It really depends on the specific needs of the application. However, most general-purpose applications tend to use AC motors, while DC motors are more commonly used in industrial or specialized applications.


Now that we have discussed the differences between AC and DC motors, it is ultimately up to the specific needs of the application as to which type of motor is better. Most general-purpose applications tend to use AC motors, while DC motors are more commonly used in industrial or specialized applications. However, there are some cases where a DC motor may be preferable.