Difference Between AC and DC Motor (With Table)

Electric motors are usually used to convert electrical energy to mechanical energy. The AC and DC motors are two types of electric motors. The concepts of AC and DC motors are popular among science students. But, these AC and DC motors are more than mere concepts and are used in real-life instances too.

AC vs DC Motor

The difference between AC and DC motors is that they use different types of current. The AC motor uses an alternative current and turns it into energy by the electric motor. The DC motor uses direct current and turns it into energy by the electric motor. Apart from this, the AC and DC motors differ in various aspects too.

AC motor is a powerful motor and is always preferred over DC motor because of their efficiency and easy availability. The power for the AC motor is supplied from the AC. AC motor involves the conversion of the Alternating current into the mechanical current. AC motor has two types, namely Synchronous motor and Asynchronous motor (also known as induction motor).

The DC motor is an electric machine or motor that uses direct current and converts electrical energy to mechanical energy. Various projects and experiments use DC motor as the source. The DC motors come in handy in several daily life instances too. There are four types of DC motors and, they serve different purposes.

Comparison Table Between AC and DC Motor

Parameters of ComparisonAC MotorDC Motor
Power sourceThe AC motors use alternating current only and do not work with anything else. The alternative current goes through the electric motor’s input and is converted as mechanical energy.The DC motors derive their current from direct current. Some of the power sources of direct current are the DC power supply and batteries. The AC to DC converter is occasionally used.
UsageThe AC motors are specifically utilized in circumstances where powerful performance is required. Also, it is used for longer periods.The DC motors come in handy in circumstances that require more motor speed. The motor speed can be limited externally.
Life expectancyThe AC motors have a longer life span. As the AC motors do not possess commutators and brushes, they have a longer life expectancy period.The DC motors have a short and limited life span. As the DC motors possess commutators and brushes, the life expectancy is limited.
Speed controlThe AC motor’s speed can be controlled by changing the frequency. This is usually performed by using an adjustable frequency drive control.The DC motor’s speed can be controlled by changing the armature winding’s current. By varying the armature winding’s current, DC motors can be kept in control.
EfficiencyThe AC motors are less efficient than DC motors. As AC motors have induction current loss and possess a motor slip, the efficiency is reduced.The DC motors are more efficient than AC motors. As DC motors do not have any induction current loss or a motor slip, the efficiency of DC motors is high.

What is AC Motor?

AC motor means Alternating current motor. AC motors get supplied with power from the Alternative current. AC motor is used for the conversion of mechanical energy from electrical energy. AC motor can be single phased as well as three phases. In terms of life span, Ac motor tends to have an extended life span.

To start the operation, the AC motor requires equipment like a capacitor. AC motor’s speed can be controlled by differing the current flow’s frequency with the help of variable frequency drive. When it comes to repairing, the AC motor is budget-friendly. It does not use brushes like a DC motor to control the current. AC motor is easily available and is always preferred over DC motor.

AC motors have two types. They are Synchronous motor and Asynchronous motor. The synchronous motor drives at a synchronous speed, and it consists of a rotor that receives energy from DC. Synchronous motor is often considered to be expensive.

On the other hand, Asynchronous motor drives at a speed less than that of a synchronous motor. It is also known as an induction motor. Asynchronous motor is used frequently due to its reliability and usefulness. Asynchronous motor is used in the operating of lift and grinders.

What is DC Motor?

The DC motor is a rotary electric motor used for the conversion of energy. The DC motor is also known as the direct current motor. This motor uses direct current to convert electric energy to mechanical energy. It is dependent on the magnetic field’s force.

The DC motors are the product of the early 19th century. When it was invented in the 1840s, dc motors were unsuccessful. The heavy battery usage required to run these dc motors was expensive and was of low quality. With the advent of rechargeable batteries, DC motors were used extensively.

An interaction occurs between an electric field and a magnetic field. A new mechanical force is produced out of the interaction between those two fields. It is the basic underlying idea behind how mechanical energy is produced. This process is also known as the motoring action.

Fleming’s left-hand rule explains the direction of the motor’s rotation. According to the rule, the middle, index and, thumb fingers are extended mutually perpendicular. The index finger points in the direction of the magnetic field. The middle finger points towards the movement of the current. The thumb shows the direction of the movement of force. The four types are Permanent magnet DC motors, shunt motors, compound motors and, series motors.

Main Differences Between AC and DC Motor

  1. The AC motors use alternating current, which is used to turn into the mechanical current. The DC motors use direct current, which is converted into mechanical current.
  2. The AC motors have three different input terminals as RYB present within them. The DC motors have two different input terminals as positive and negative are present within them.
  3. The AC motors are controllable by changing the frequency of the motor. The DC motors can be limited by changing the armature winding’s current.
  4. The AC motors are very slow in responding to the change in load. The DC motors are very quick in responding to the change in load.
  5. The AC motors are less efficient because of the induction current loss and motor slip. The DC motors are more efficient because there is no induction current loss and motor slip.

Conclusion

The AC motors and DC motors differ in their components and even in their uses. The AC and DC motors are frequently used in scientific studies, especially in physics. Apart from its academic uses and experiments, AC motors and DC motors are used in real life too.

The AC motors are generally used in large industries as it provides powerful performance for a long period. In contrast, DC motors are generally used in small domestic appliances. The AC and DC motors have their own applications in our daily lives. These are the differences between the alternative current motors and direct current motors.

References

  1. https://doi.org/10.1109/T-AIEE.1941.5058394
  2. https://doi.org/10.1109/41.873209
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