Diferenças entre MOTORES de CORRENTE ALTERNADA e MOTORES de CORRENTE CONTÍNUA.

Fundamentals of DC motors versus AC motors What's up Engineering Lovers, my name is Gustavo Pereira and today I want to tell you a little about the difference between DC motors and AC motors. The main purpose of all electric motors is to transform electrical energy into mechanical energy. They provide a rotary motion, where torque and power can be mechanically matched with pulleys and gears, and in this way, torque or rotation can be increased or decreased depending on the type of application.

There are a wide variety of electric motors, and the proper choice of motor makes the difference between an efficient, long-lasting motor and a troublesome, inefficient machine. One of the important characterizations of the motor is whether the motor operates on alternating current (AC) or direct current (DC). Both types of motors have their advantages and disadvantages, as well as some special considerations for their use in an industrial environment.

So let's explore these differences AC motors are able to rotate by converting an alternating electric current into a rotating magnetic field. The rotating magnetic field is then used to rotate the rotor, which is connected to the output shaft. At this point it can be connected to the most varied applications, such as overhead cranes, conveyor belts, pumps, fans, and much more.

In a very simple explanation, alternating current enters the stator, which consists of coils. As the current changes direction in the stator, it generates the magnetic field. The stator, as the name suggests, is static, that is, it does not move, but the alternating current flowing through it creates the changing magnetic field.

The magnetic field pushes the rotor, causing it to rotate and turning the output shaft. AC motors can generally be connected in a variety of ways depending on whether they are used in a single-phase or three-phase configuration. Direct current motors also have a stator.

However, in a direct current motor, the stator is made up of a set of two permanent magnets, of opposite polarity, instead of the wire coil used by an AC motor. Between the two permanent magnets is an armature, or rotor, which consists of loops of wire wound around a piece of metal. At the end of the armature is a commutator, which is simply a set of thin , flat plates for current to flow as the motor rotates.

Finally, the DC power supply is connected to a set of carbon brushes, which transfer current to the commutator. When the DC power supply is turned on, current flows through the carbon brush, to the commutator, and then to the circuit. This generates a magnetic field that repels one permanent magnet and attracts the other.

As the motor rotates, the contact between the carbon brush and the commutator is broken and then reconnected to the opposite side. This reverses the polarity of the armature, causing it to continue rotating. But where should I use each type of engine?

AC motors are great for industrial applications where the motor speed may need to be variable. AC motor speeds can be controlled using a frequency inverter, where the change in frequency will change the speed of the motor. This allows AC motors and frequency inverters to be used in a wide range of applications that require motor speed control.

For example, imagine an assembly line that has to start and stop repeatedly. Now imagine that you are on this assembly line carrying bottles vertically. Starting and stopping must be carried out carefully so as not to tip over or break the grips.

In general, for motors of the same power, AC motors are physically lighter. This is because the equivalent power direct current motor requires a large permanent magnet for its stator which is heavier than the coils used in the stator for the AC motor. Direct current motors have the advantage of starting faster and providing high torque for starting.

This is particularly useful for large, stationary equipment. However, DC motors have the advantage of mobility, they can be used in battery powered devices such as electric cars and portable electronics. Most small battery-powered consumer goods that have moving parts contain direct current electric motors.

In terms of maintenance, the biggest problems are windings and bearings. This is usually due to overheating, lack of lubrication in the bearings, and excessive current consumption in the wiring. Bearings can be lubricated as part of regular engine maintenance, and on more expensive engines, accelerometers can measure vibration.

On the other hand, wire overheating can be detected in advance by measuring and archiving the current data in the motor. Direct current motors may also require maintenance on the carbon brushes and springs that push the carbon brushes against the commutator. Well, this was just a brief introduction on the subject, but if you want to know more details and get to know this world of electric motors in depth, I have a tip for you.

Check out Professor Marcus Vinicius Ferraz do Amaral's channel. I had the pleasure of taking classes at the college with Professor Marcus Vinicius, and it is an honor to be able to make this recommendation here. In his channel you will find the most varied topics about electrical machines, such as synchronous motors, asynchronous motors, direct current motors, harmonic components, and much more.

I'll leave a link to the channel here in the description, so I didn't forget to subscribe. Choosing the right electric motor for a given application requires careful thought and some understanding of the physics around electromagnetic fields. Motor size, torque and speed requirements should also be researched and compared to the specific application.

It also requires an assessment of the location, power supply and control system needed to operate the motor. Once an engine has been chosen and installed, it is up to engineers and technicians to develop a regular maintenance schedule and record engine health data so problems can be detected before they happen. I'll leave two videos here that you might like too, so click on one of them to check it out.

Don't forget to like the video, subscribe to the channel and take the opportunity to share the video on your social networks. That's it my friends, a big hug, and see you in the next ED News.