A DC motor or direct current motor is a type of rotary electric motor that converts direct current (DC) electrical energy into mechanical energy. The most common types are based on magnetic field forces. Almost all types of DC motors have an internal mechanism, either electromechanical or electronic, that changes the direction of current in a portion of the motor regularly.
DC motors were the first widely used type of motor because they could be powered by existing direct-current lighting power distribution systems. The speed of a direct current motor can be varied over a wide range by varying the supply voltage or changing the current strength in its field windings. Small direct current motors are found in tools, toys, and appliances.
The universal motor is a lightweight brushed motor that can operate on direct current and is used for portable power tools and appliances. Larger DC motors are currently used in electric vehicle propulsion, elevator and hoist drives, and steel rolling mill drives. With the advent of power electronics, it is now possible to replace DC motors with AC motors in many applications.
Working
A DC motor operates on the principle that when a current-carrying conductor is placed in a magnetic field, it generates mechanical force. The left-hand rule determines the force’s direction. Because DC motors and DC generators are built the same way, they can be used interchangeably.
Types of DC Motors
It is necessary to understand the various types of DC motors to appreciate their benefits. Each type of DC motor has advantageous characteristics that must be considered before purchase and use. One of the primary advantages of direct current (DC) motors over alternating current (AC) motors is their ease of installation and low maintenance.
The connections between the field winding and the armature distinguish DC motors. The field winding can be connected in series or parallel to the armature. In some cases, the link is both parallel and serial.
Another distinction between DC motors is whether the rotor is brushed or brushless. Brushes apply current to the rotor in brush DC motors. A permanent magnet is used in the rotor of a brushless DC motor.
Because DC motors are ubiquitous and used in a wide range of applications, each application requires a different type. Regardless of your need for DC motors, it is critical to understand each type because they are present in almost every aspect of life.
Brushed DC Motor
A brush’s magnetic field A direct current motor is created by passing a current through a commutator and a brush that is connected to the rotor. Brushes are made of carbon and can be excited separately or simultaneously. The stator is the enclosure that houses the motor’s components and the magnetic field. The coil on the rotor can be wound in series or parallel to form a series wound DC motor or a shunt wound DC motor.
The commutator is an electrical switch that allows current to flow back and forth between the rotor and the external power source. It is a technique for applying electrical current to windings and producing a constant rotating torque by reversing the current direction.
The commutator sections are connected to the rotor windings via a set of contact bars installed in the motor’s shaft.
DC motors are classified into three types: separately excited, self-excited, and permanent magnet. In the stator structure of the separately excited and self-excited, an electromagnet is used. The magnetic field is created by a powerful magnet in the case of a permanent magnet.
Shunt, series, and compound self-excited DC motors are the three types. The compound exciting type is divided into cumulative and differential types, each with short and long shunts.
Brushless DC Motor
Brushless direct current motors are made up of a permanent magnet rotor and a coil wound stator. Brushes are not required in this DC motor design. The benefit of a brushless DC motor is that it eliminates brush wear and tear because the rotating magnet produces very little heat. Brushless DC motors are more expensive due to their efficiency.
Applications of DC Motors
- AIR conditioners.
- Computer drives
- Electric toothbrushes
- Portable vacuum cleaners. Drilling machines,
- trimmers,
- Food mixers
- drones
- Traction systems
- Sewing machines
- Cranes
- Air compressors. etc
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