DC motors refer to devices that convert electrical energy into mechanical energy. DC stands for ‘direct current’, and these equipment specifically use this form of energy and transform it into mechanical rotations. Such devices primarily leverage magnetic fields associated with electric current and ascribe rotation to a motor. These motors, in turn, ensure the rotation of an output device attached to them.
However, there are several types of DC motor about which you should know. Such models use two categories of currents – through rotors and start windings. The latter of these two provide magnetic fields that help these motors function.
How Does a DC Motor Function?
As per DC motor definition, a source of direct current generates mechanical energy from electrical energy. These devices usually possess a magnetic device, which may be permanent or electromagnetic. Besides, they comprise a stator, armature, rotor, and a commutator containing brushes.
When you supply electric current through the armature, or a coil, a magnetic field springs into action. This field, in turn, reacts with the installed magnet and produces a specific torque. Therefore, you can see a rotation in the motors. The commutator regulates the flow of current among the coils.
On the other hand, it also acts as a link between stationary power sources and armature by implementing conductive rods.
What are the Types of DC Motors?
If you are wondering how many types of dc motor are there, you have come to the right place to acquire knowledge.
Notbably, the kinds of DC motor include the following –
Permanent Magnet DC Motor – This category of DC motor uses permanent magnets in the form of poles. These magnets usually remain mounted inside the periphery of a cylindrical steel stator. This stator, in turn, helps receive the magnetic flux.
The torque for shaft rotation leverages the contact between rotor conductors which carry axial current and permanent magnets. In this device, the flux remains constant. However, armature voltage control, rheostat control, and chopper control techniques help in controlling both speed and torque.
Series Motor – Series motor is one of the different types of DC motors that use the self-excited technique. It is because field winding connects to the armature winding in series and internally. This type of DC motor comprises a stator, rotor, and commutator brush.
In this case, the stator consists of field winding, and rotors carry armature conductors. However, field coils constitute fewer field winding since the armature current is the field current.
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Furthermore, torque in series DC motors is directly proportional to the current. The torque produces the motor speed, which finds industrial application in cranes.
Shunt Motor – In this case, the field winding links with armature windings of the motor, placed in parallel. It forms another type of self-excited motor. Both of these components have a steady supply of the same voltages. However, armature windings ensure the excitement of this shunt field. As a result, these offer a greater regulation of speed and also have the option of reverse control.
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Compound DC Motor – This DC motor and type comprises both the functions of series and shunt motors. These distinct categories of field coils generate appropriate magnetic flux. Also, it connects to the armature coil and produces a torque that becomes adequate for rotation at a required speed.
This category of DC motor combines effective speed regulation properties of shunt motor and high starting torque characteristics of a series motor.
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Short Shunt DC Motor – This motor leverages the parallel connection between shunt field winding and armature winding. The series field coil interacts with the supplied current. After that, it diverges into the armature.
Long Shunt DC Motor – Long shunt DC Motor links in parallel with the series field coil along with the armature. These, in turn, interact with each other in series.
How to Classify DC Motors?
The classification of DC motors include the following –
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Now that you know DC motor types and working, keep an eye on the related topics to gather further knowledge on this subject. Also, you can download our Vedantu app for a personalized learning experience along with convenience of access.
FAQs on Types of DC Motor
1. What is a DC motor and how does it convert electrical energy into mechanical energy?
A DC motor converts electrical energy from direct current into mechanical energy through the interaction of magnetic fields produced by the armature and the field windings. This process occurs as current flows in the armature, generating a force that rotates the motor's shaft.
2. Which major types of DC motors are included in the CBSE syllabus and what distinguishes them?
The main types of DC motors as per the CBSE 2025–26 syllabus are:
- Separately Excited DC Motors: The field winding is powered separately from the armature.
- Self-Excited DC Motors: The field winding is powered by the motor’s own armature. Subtypes include shunt-wound, series-wound, and compound-wound DC motors.
- Permanent Magnet DC Motors: Use permanent magnets instead of field windings.
3. How does a shunt-wound DC motor differ from a series-wound DC motor in terms of application and characteristics?
Shunt-wound DC motors have the field winding connected in parallel with the armature, providing constant speed and are used where speed regulation is important. Series-wound DC motors have their field winding in series with the armature, resulting in high starting torque, making them suitable for applications like traction and cranes.
4. What is the function of the armature and field winding in a DC motor?
The armature produces motion by interacting with the magnetic field generated by the field winding. Together, they create the torque required to turn the motor shaft and drive mechanical loads.
5. Why are permanent magnet DC motors preferred in certain applications?
Permanent magnet DC motors are preferred for their compact size, high efficiency, and simplified construction since they do not require field windings or external excitation. They are ideal for portable devices and battery-operated equipment.
6. What is the significance of short shunt and long shunt configurations in compound DC motors?
In a short shunt compound DC motor, the shunt field winding is connected only in parallel with the armature. In a long shunt compound DC motor, the shunt field winding is parallel to both the armature and series field winding. This affects the motor’s performance and speed regulation.
7. How does the working principle of a DC motor demonstrate Fleming's Left-Hand Rule?
The working principle of a DC motor is based on Fleming's Left-Hand Rule, which states that when a current-carrying conductor is placed in a magnetic field, a force acts perpendicular to both. This force causes the armature to rotate, generating mechanical work.
8. What factors should be considered while selecting a type of DC motor for industrial use?
Selection of a DC motor type depends on:
- Required speed regulation
- Starting torque
- Load characteristics
- Efficiency and cost
- Maintenance requirements
9. How can one identify if a misconception exists about the uses of compound DC motors in examination questions?
A common misconception is that compound DC motors are only used where high torque is needed. In reality, they are chosen for applications that require both good starting torque and stable speed regulation, offering a balance between shunt and series types.
10. What role do DC motors play in real-world devices covered under the CBSE curriculum?
DC motors are widely used in fans, mixers, electric vehicles, and robotics. Their ability to control speed and torque precisely makes them critical in applications that require variable speed or high starting power.
