Difference Between DC Motors and AC Motors (With Table)

The term “motor” simply means that an electrical machine whose motive is to transform electrical energy into mechanical energy. It helps to make something work by its force. When the magnetic field interacts with direct (DC) or alternating (AC) current, it generates force within the motor. 

Motors can be used in industries, workplaces, and even at house. From a toy to pull elevators, motors are used depending on their size and power. Motors can be majorly classified into two types: DC and AC motors. 

DC Motors vs AC Motors 

The main difference between DC motor and AC motor is that they both have different power sources. DC motors get power from direct current (DC). On the other hand, AC motors get power from alternating current (AC). The life expectancy of DC motors is shorter than that of AC motors. This is because DC motors use brushes while their construction as well as commutator too. 

DC motor is one of the classes of the electric motor which changes electrical energy into mechanical energy. The speed can be controlled with the help of varying the winding’s current. They were widely used due to their capability of getting power by lighting power distribution system of existing direct current. Some famous brands of DC motors are crouzet, RS PRO, and maxon. 

The main motive of the AC motor is to convert the electrical input signal into mechanical energy. AC linear motors work on the same principles as rotating motors but the only difference is their parts are arranged in a straight line. There are different types of AC motors that have different output abilities and operating characteristics. Some famous brands of AC motors are Panasonic, ABB, and DKM AC motors, etc. 

Comparison Table Between DC Motors and AC Motors 

Parameters of comparisonDC motorsAC motors
PowerFrom Direct CurrentFrom Alternating Current
Life spanShorterLonger
Frequency0 (in India)50 Hz (in India)
PhaseOnly single phaseSingle-phase or three-phase
Repairing costNot costlyCostly

What is DC Motors? 

DC motor or direct current motor is one of the types of the electric machine whose main motive is to transfer electrical energy into mechanical energy. As this motor is based on DC it uses electrical power from direct current. Later, it converts this energy for the mechanical rotation of the motor. Majorly range of DC motors works on internal mechanism change the current’s direction. 

DC motors can be used in small toys to large appliances such as pull elevators due to their differentiation in terms of power and size. The DC motor is a constituent of the stator which stands stationary. And an armature whose main role is to rotate. As a result, magnetic fields are produced by the stator and in return armature drives in rotate motion. 

In 1832, the DC motor was invented by William Sturgeon. The invention of the DC motor contributed a lot in reshaping the face of the industry and hence, led to development because many new appliances were invented based on DC motors. DC motors can be classified majorly into four types: brushless, brushed, shunt, and series DC motors. 

Each type of DC motor has its advantages which are made for specific use. There are several appliances available in the market which makes day-to-day life easier. Small DC motors are used at home in several household appliances and toys. For industrial purposes, large DC motors are used to brake and reverse applications. 

What is AC Motors? 

AC motor or alternating current motor is one of the types of motor which is common. As this motor is based on AC, this motor works with the help of alternating current. The main motive of an AC motor is to produce mechanical energy from the electrical input signal. As a result, the current which flows around the circuit takes the help of alternating to produce mechanical energy. 

In 1887, the AC motor was invented by Nikola Tesla. AC motors are used in industries, workplaces, and at home due to their ease of operation, durability, general affordability, and low manufacturing costs. Clocks, audio turntables, disk drives, power tools, fans, and washing machines are some of the appliances which use AC motors. 

In AC motors, flow around a circuit at regular intervals gets reversed or it can be said that on AC circuit voltage changes periodically. An alternator is a device on which AC motors rely because it helps to produce alternating current direction. The alternator generates an electromagnetic field when electricity passes through the rotor and itself turns around the stator. 

There are many types of AC motors are available in the market such as brushless, squirrel cage, shaped-pole AC motors, and many more. But among them induction and synchronous AC motors are common. The speed of the induction motor is less than synchronous but the speed of the synchronous motor is irrespective of the load. 

Main Differences Between DC Motors and AC Motors 

  1. DC motors are preferred when you control externally the speed of the motor. On the flip side, AC motors are useful if the power performance is required for a longer period. 
  2. When it comes to magnitude and direction, DC motors have constant and it flows only in one direction. On the other hand, in AC motors, the current reverses on a periodical basis. 
  3. In terms of controlling the speed of motors, by varying the winding’s current of an armature, DC motors’ speed can be controlled. But by varying the current’s frequency, AC motors can be controlled.  
  4. In DC motors, the magnetic field is left with no rotation but the armature does rotate. Whereas in AC motors, magnetic fields constantly rotate but there is no movement in armatures. 
  5. To start any operation, external help is not required in DC motors. While in AC motors, external help is required or starting equipment such as a capacitor to start any effective operation. 

Conclusion 

So, it can be concluded that motors play an important role from industry to home. As they can be used in toys to huge appliances such as pull elevators. DC and AC motors are two of the major classification of motors. There is one common function of DC and AC motors is that they both transform electrical energy into mechanical energy. 

But they can be differentiated based on the source of power. DC motors use direct current to power themselves whereas, AC motors use alternating current. The speed of both motors can be controlled by different measures when armature winding current is varied, speed of DC motors can be controlled. While by varying the frequency, the speed of AC motors can be controlled. 

References 

  1. https://ieeexplore.ieee.org/abstract/document/90349/
  2. https://ieeexplore.ieee.org/abstract/document/282477/
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2D vs 3D