DC Motor electrical technology electrical engineering
- 1. DC Motor Types and Applications Submitted To: Engr. Asad Munir Submitted by: Aman Fatima (22013123-031), Akasha Fiaz (22013123-011), Ayesha Ishtiaq (22013123-005), Ayesha Azmet (22013123-026), Salman Sajeel (22013123-012) Course: Electrical Technology (CHE-202)
- 2. DC Motor • Defination: A DC motor is defined as a class of electrical motors that convert direct current electrical energy into mechanical energy. • DC Motor Construction Parts:
- 3. Different Parts of DC motors A DC motor is composed of the following main parts: • Armature or Rotor: The armature of a DC motor is a cylinder of magnetic laminations that are insulated from one another. The armature is perpendicular to the axis of the cylinder. The armature is a rotating part that rotates on its axis and is separated from the field coil by an air gap. • Field Coil or Stator: A DC motor field coil is a non-moving part on which winding is wound to produce a magnetic field. This electro-magnet has a cylindrical cavity between its poles.
- 4. Different Parts of DC motors • Commutator: The commutator of a DC motor is a cylindrical structure that is made of copper segments stacked together but insulated from each other using mica. The primary function of a commutator is to supply electrical current to the armature winding. • Brushes: The brushes of a DC motor are made with graphite and carbon structure. These brushes conduct electric current from the external circuit to the rotating commutator. Hence, we come to understand that the commutator and the brush unit are concerned with transmitting the power from the static electrical circuit to the mechanically rotating region or the rotor.
- 5. DC Motor Working • A magnetic field arises in the air gap when the field coil of the DC motor is energised. The created magnetic field is in the direction of the radii of the armature. The magnetic field enters the armature from the North pole side of the field coil and “exits” the armature from the field coil’s South pole side. Construction of Torque in the DC motor
- 6. DC Motor Working The conductors located on the other pole are subjected to a force of the same intensity but in the opposite direction. These two opposing forces create a torque that causes the motor armature to rotate. • Working principle of DC Motor: When kept in a magnetic field, a current-carrying conductor gains torque and develops a tendency to move. In short, when electric fields and magnetic fields interact, a mechanical force arises. This is the principle on which the DC motors work.
- 7. Types Of DC Motor
- 8. Types of DC Motor: DC Motor are classified into different types based on the field winding connections to the armature as: 1. Self Excited DC Motor 2. Separately Excited DC Motor 3. Permanent Magnet DC Motor Now, let us discuss the various types of DC Motors in detail: • Self Excited DC Motor In self-excited DC motors, the field winding is connected either in series or parallel to the armature winding. Based on this, the self-excited DC motor can further be classified as: 1. Shunt wound DC motor 2. Series wound DC motor 3. Compound wound DC motor
- 9. Shunt Wound DC Motor • In a shunt wound motor, the field winding is connected parallel to the armature as shown in the figure.
- 10. Series Wound DC Motors • In a series wound DC motor, the field winding is connected in series with the armature winding as shown in the figure.
- 11. Compound Wound DC Motor DC motors having both shunt and series field winding is known as Compound DC motor, The compound motor is further divided into: • Cumulative Compound Motor • Differential Compound Motor Cumulative Compound Motor: In a cumulative compound motor, the magnetic flux produced by both the windings is in the same direction. Differential Compound Motor: In a differential compound motor, the flux produced by the series field windings is opposite to the flux produced by the shunt field winding.
- 12. Compound Wound DC Motor
- 13. Short Shunt DC Motor • If the shunt field winding is only parallel to the armature winding and not the series field winding then its known as short shunt DC motor or more specifically short shunt type compound wound DC motor. The circuit diagram of a short shunt DC motor is shown in the diagram below.
- 14. Long Shunt DC Motor • If the shunt field winding is parallel to both the armature winding and the series field winding then it’s known as long shunt type compounded wound DC motor or simply long shunt DC motor. The circuit diagram of a long shunt DC motor is shown in the diagram below.
- 15. Separately Excited DC motor • In a separately excited DC motor, the field coils are energised from an external source of DC supply as shown in the figure.
- 16. Permanent Magnet DC Motor • The permanent magnet DC motor (also known as a PMDC motor) consists of an armature winding as in case of an usual motor, but does not necessarily contain the field windings.
- 17. Brushless DC Motor • A brushless DC motor, also known as synchronous DC motor, unlike brushed DC motors, do not have a commutator. The commutator in a brushless DC motor is replaced by an electronic servomechanism that can detect and adjust the angle of the rotor.
- 18. Brushed DC Motor A brushed DC motor features a commutator that reverses the current every half cycle and creates single direction torque. While brushed DC motors remain popular, many have been phased out for more efficient brushless models in recent years.
- 19. Applications of DC Motors The applications of different types of DC motors are listed below: • Shunt DC Motors Owing to the fairly constant speed and medium starting torque of shunt DC motors, they are used in the following applications: 1. Centrifugal and reciprocating pumps 2. Lathe machines 3. Blowers and Fans 4. Drilling machines 5. Milling machines 6. Machine tools
- 20. Applications of DC Motors • Series DC Motors Owing to the high starting torque and variable speed of series DC motors, they are used in the following applications: 1. Conveyors 2. Hoists, Elevators 3. Cranes 4. Electric Locomotives • Cumulative Compound DC motors Owing to the high starting torque of cumulative compound DC motors, they are used in the following applications:
- 21. Applications of DC Motors 1. Shears 2. Heavy Planers 3. Rolling mills 4. Elevators
- 22. END