The working principle of the brushless motor is just the reverse of the former. Electromagnets are used for spinning the motor. A brushed motor is an electric motor that uses direct current to do the required work.
It uses an armature, which functions as an electromagnet. This is used on the external rotor. There is a physical commutator for turning the rotor on. The poles of the electromagnet rub back and forth against that of the permanent magnet, which gradually forms a direct current.
Brushed motors have been in use since the late s. They are highly preferred for commercial and industrial usage. There are four basic components in a brushed motor: the stator, the rotor, brushes, and a commutator. The speed of the motor can be adjusted by changing the voltage amount of the magnetic field strength that is formed within them. Brushed motors have zinc and pressed steel coating on them, along with a cap made up of plastic, fixed at one of the ends.
The coating and cap usually have quite a few holes in order to facilitate airflow although the motor, for preventing it from overheating. Screw holes are also present for fixing the motor in position.
The cap also contains connection pins that come in pairs for the power supply connection. Brushed motors are widely used in households. For example, electric toy cars, electric toothbrushes, bread slices, etc. In other machines such as cranes, mills, drills, etc. A brushless motor is another type of DC motor. It also uses direct current for its functioning. Brushed motors can be varied in speed by changing the operating voltage or the strength of the magnetic field within them.
We'll discuss how these components work in conjunction with the next section. As previously mentioned, a brushed motor consists of four basic components. The first, called the stator, generates a stationary magnetic field that surrounds the rotor. Top right: from left to right the plastic cap with exposed brushes, the rotor with the commutator and electromagnetic windings, and the casing showing permanent magnets and stator inside.
This magnetic field is generated using two curved permanent magnets. These magnets are usually stationary do not move , hence the term. It is also important to note that one will have its North pole pointing towards the rotor, and the other its south pole toward the rotor. The rotor, or armature, is made up of wire coils that can, when electricity is run through them, produce a magnetic field. This is the part that moves hence the name 'rotor' and turns the main shaft of the motor.
When electricity is run to the motor a magnetic field is generated that attracts and repels against the fixed magnets in the stator. In order to keep the rotor spinning, the magnetic field needs to be reversed every degree turn of the rotor in a simple single-armature brushed motor. This change in rotor magnetic polarity is performed by the motor's brushes usually made of carbon and a commutator the part that "commutes" or reverses the electrical current to the rotor's armature.
The brushes are usually just two fixed electrodes that rub against the commutator ring as it spins with the rotor. The brushes will also tend to be spring-loaded to ensure they remain in contact with the commutator. The commutator usually consists of a small, usually copper, cylinder attached to the rotor with breaks at regular intervals e,g, degrees in a single armature rotor. Electrical current will flow through one half of the commutator, through the armature, and back out of the other half of the commutator.
As the rotor armature spins, the also commutator spins, constantly making and breaking an electrical circuit with the brushes. This causes the magnetic poles of the rotor's windings to flip magnetic polarity as the circuit is broken in one direction and reconnected in the other -- i. More complex motors will have a series of armatures with breaks between them on the commutator. This helps prevent potential seizing of the motor if the brushes complete a circuit across the commutator gaps.
Pretty neat. In real motors, armatures will also consist of a mass of wires instead of a single wire. This helps greatly improve the strength of the electromagnet and therefore the torque of the motor. Typically, brushed DC motors are housed in a pressed steel and zinc coated housing with a plastic cap on one end.
The housing and cap will usually have a series of holes that are generally present to allow airflow through the motor to help prevent overheating. There are also usually screw holes too for mounting the motor in place.
The plastic cap will also hold a pair of connection pins for connecting the power supply and preventing shorting through contact with the metal motor housing. If you are having trouble visualizing how a DC brushed motor works, here is a great simulation. Whenever a means of converting electricity into rotational motion is required, chances are you will find a brushed DC motor. Here's what separates them in terms of excitation, starting mechanism, efficiency and applications.
Thursday April 16, Views. Here's an article that explains how a Servo Motor works? Monday March 15, Views. The electrical motor is the biggest advancements in the engineering and technology field ever since the invention of electricity Your email address will not be published. What is a Brushed DC Motor? What is a Brushless DC Motor? Tags : DC motor , motor , types of DC motor.
Share This Article. About Robu. Related Posts. Leave a comment Cancel reply Your email address will not be published. Brushed DC motor. Brushless DC motor. It uses brushes to deliver current to the motor windings through mechanical commutation. It uses Electrical commutation to deliver the current.
High- because of the absense of brushes and commutator. Higher rotor inertia which limits dynamic characterstics.
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