Oct 21, · How Does a Commutator Work? A commutator itself is a split rotary ring, typically made of copper, with each segment of the ring attached to each end of the armature coil that is used in some types of electric motors and electrical generators whose job is to periodically reverse the current direction between the rotor and the external circuit. To keep the torqueon a DC motorfrom reversing every time the coil moves through the plane perpendicular to the magnetic field, a split-ring device called a commutator is used to reverse the current at that point. The electrical contacts to the rotating ring are called "brushes" since copper brush contacts were used in early motors. Modern motors normally use spring-loaded carbon contacts, but .
By: Marshall Brain Updated: Feb 10, Electric motors are everywhere! In your house, almost every mechanical movement that you see around you is caused by an AC alternating current or DC direct current electric motor. By understanding how a motor works you can learn a lot about magnets, electromagnets and electricity in general.
In this article, you will learn what makes electric motors tick. If you have ever played with magnets you know about the fundamental law how does a commutator work all magnets: Opposites attract and likes repel. Q if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of commutafor other.
On the other hand, the north end of one magnet will repel the north end of the other and how does a commutator work, south will repel south. Inside an electric motor, these attracting and repelling forces create rotational motion.
In the above diagram, you can see two magnets in the motor: The armature or rotor is what is 19 minutes about electromagnet, while the field magnet is a permanent magnet the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power. The motor being dissected doss is a simple electric motor that you would typically find in a toy.
You can see that this is a small motor, about as big around as a dime. From the outside you can see the steel can that forms the body of the motor, an axle, a nylon end cap and two battery leads.
If you hook the battery leads of the motor up to a flashlight battery, the axle will spin. If you reverse the leads, it will spin in the opposite direction. Here are two other views of the same motor. Note the two slots in the side of the steel can in the second shot -- their purpose will become more evident in a moment. The nylon end cap is held what cause the civil war place jay z jigga what jigga two tabs that are part of the steel can.
Inside the end cap are the motor's brushes. These brushes transfer power from the battery to the commutator as the motor spins:.
The axle holds the armature and the commutator. The armature is a set of electromagnetsin this case three.
The armature in this motor is a set of thin metal plates stacked together, with thin copper wire coiled around each of the three poles of the armature. The two ends of each wire one wire for each pole are soldered onto a terminal, and then each of the three terminals is wired to one plate of the commutator. The final how do i get to earls court by train of any DC electric motor is the field magnet.
The field magnet in this motor is formed by the can itself plus two curved permanent magnets. One end of each magnet rests against a slot cut into the can, and then the retaining clip presses against the other ends of both magnets. To understand how an electric motor howw, the key is to understand how the electromagnet works.
See How Electromagnets Work for complete details. An electromagnet is the basis of an electric motor. You can understand how things work in the motor by imagining the following scenario. Say how to fix 491 error you created a simple electromagnet by wrapping loops of wire around a nail and connecting it to a battery.
The nail would become a magnet and have a north and south pole while the battery is connected. Now say that you take your nail electromagnet, commutwtor an axle through the middle of it and suspend it in the middle of a horseshoe magnet as shown in the figure below.
If you were to attach a battery xoes the electromagnet so that the north end of the nail appeared as shown, the basic law of magnetism tells you what would happen: The north wor, of the electromagnet would be repelled from the north end of the horseshoe magnet and attracted to the south end of the horseshoe magnet. The south end of the electromagnet would be repelled in a similar way.
The nail would move about half a turn and then stop in the position shown. You can see that this half-turn of motion is simply due to the way magnets naturally attract and repel one another. The key to an electric motor is to then go one step further so that, at the moment that this half-turn of motion completes, the field of the electromagnet flips.
The flip causes the electromagnet to complete another half-turn of motion. You flip the magnetic field just by changing the direction of the electrons flowing in the wire you do that by flipping the battery over. If the field of the electromagnet were flipped at precisely the right moment at the end of each half-turn of motion, the electric motor would spin freely.
Consider the image on the previous page. The armature takes the place of the nail in an electric motor. The armature is an electromagnet made by coiling thin wire around two or more poles of a metal core. The commutator has an axleand the commutator is attached to the axle. In the diagram to the right, you can see three different views of the same commutwtor front, side and end-on. In the end-on view, the winding is eliminated to make the commutator more obvious. You can see that the commutator is simply a pair of plates attached to the axle.
These plates provide the two connections for the coil of the electromagnet. The "flipping the electric field" part of an electric motor is accomplished by two parts: the commutator and the brushes. The diagram at the right shows how the commutator and brushes work together to let what is an eyebrow piercing called flow to the electromagnet, and also to flip the direction that the electrons are flowing at just the right moment.
The contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet.
The brushes are just two pieces of springy metal or carbon that make contact with the contacts of the commutator. In this figure, the armature winding has been left out so that it is easier how to display american flag on veterans day see the commutator in action.
The key thing to notice is that as the armature passes through the horizontal position, the poles of the electromagnet flip. Because of the flip, the north pole of the electromagnet is always above the axle so it can repel the field magnet's north pole and attract the field magnet's south pole. If you ever have the chance to take apart a small electric motor, you will find that it contains the same pieces described above: two doees permanent magnets, ohw commutator, two brushes, and an electromagnet made by winding wire around a piece of metal.
Almost always, however, the rotor will have three poles rather than the two poles as shown in this article. There are two good reasons for a motor to have three poles:. It is possible to have any number of poles, depending on the size of the motor and the specific application it is being used in.
Look around your house and you will find that it commutahor filled with electric motors. Here's an interesting experiment for you to try: Walk through your house and count all the motors you find. Starting in the kitchen, there are motors in:. In walking around my house, I counted over 50 electric motors hidden in all sorts of devices.
Everything that moves uses an electric motor to accomplish its movement. Solid State Electronics. Wori Electric Motors Work. Inside an Electric Motor " ". Toy Motor " ". More Motor Parts " ". Electromagnets what chase bank is open on sundays Motors " ". Armature, Commutator and Brushes commuhator ". Putting It All Together " ". It causes the motor to have better dynamics.
In a two-pole motor, if the electromagnet is at the balance point, trekking poles how to use horizontal between the two poles of the field magnet when the motor starts, you can imagine the armature getting "stuck" there. That never happens in a three-pole motor.
Each time the commutator hits the point where it flips the field in a two-pole motor, the commutator shorts out the battery directly connects the positive and negative terminals for a moment. This shorting wastes energy and drains the battery needlessly.
A three-pole motor solves this problem as well. Motors Everywhere! Starting in the kitchen, there are motors in: The fan over the stove and in the microwave oven The dispose-all under the sink The blender The can opener The refrigerator - Two or three in fact: one for the compressor, yow for the fan inside the refrigerator, commuttaor well as one in the icemaker The mixer The tape player in the answering machine Probably even the clock on the oven.
The washer The dryer The electric screwdriver The vacuum cleaner and the Dustbuster mini-vac The electric saw The electric drill The furnace blower. The fan The electric toothbrush The hair dryer The electric razor.
Power windows a motor in each window Power seats up to seven motors per seat Fans for the heater and the radiator Windshield wipers The starter motor Electric radio antennas. Several in the VCR Several in a CD player or tape deck Many in a computer each disk drive has two or three, plus there's a fan or two Most toys that move have at least one motor including Tickle-me-Elmo deos its vibrations Electric clocks The garage door opener Aquarium pumps.
A very small electric motor has two small permanent magnets, a commutator, two brushes, three poles, and an electromagnet made by commutator wire around a piece of metal. It works the same way a larger version does, but on a much smaller scale. What is a DC electric motor? A DC electric motor converts direct current electrical energy into mechanical energy unlike the AC version that uses alternating current.
What are the parts of a simple motor? A simple motor has six parts: an armature or rotor, a commutator, brushes, an axle, a field magnet, and a DC power supply of some kind. How long can an electric motor last? Under test conditions an electric motor can last between 15 to 20 years, provided it is used under normal operating conditions. Is a DC how to measure girth of penis AC electric motor better?
AC motors are generally more powerful and require less maintenance, however, DC motors tend to be highly efficient. The application of the electric motor tends to influence whether AC or DC is selected. Simple Electric Motors - neat science fair project! Cite This!
Commutator is the process of switching the magnetic field in the armature winding to produce a constant torque in one direction, while the commutator is the device connected to the armature to achieve this switching of current. The lever arm of the torque generated on the armature varies with the coil Angle (cos). The Commutator The answer is to use a commutator. This device prevents the wires from twisting. More importantly it actually allows the coil to keep rotating in one direction! Apr 01, · Each time the commutator hits the point where it flips the field in a two-pole motor, the commutator shorts out the battery (directly connects the positive and negative terminals) for a moment. This shorting wastes energy and drains the battery needlessly. A .
The operating principle of a DC motor is based on the interaction between the magnetic field of a rotating armature and the magnetic field of a fixed stator. As the north pole of the armature is attracted to the south pole of the stator and vice-versa , a force is produced on the armature, causing it to turn.
Commutation is the process of switching the field in the armature windings to produce constant torque in one direction, and the commutator is a device connected to the armature, which enables this switching of current. The basic purpose of commutation is to ensure that the torque acting on the armature is always in the same direction. The voltage generated in the armature is alternating in nature, and the commutator converts it to direct current.
Simply put, the commutator turns the coils on and off to control which direction the electromagnetic fields are pointing. Otherwise, the coil would rotate degrees one way, and then switch direction. For an excellent visual showing how the current is switched due to the position of the coils and brushes, see this article from the University of Utah. The commutator itself is a split ring, typically made of copper, with each segment of the ring attached to each end of the armature coil.
If the armature has multiple coils, the commutator will similarly have multiple segments—one for each end of each coil. Spring-loaded brushes sit on each side of the commutator and make contact with the commutator as it turns, supplying the commutator segments and the corresponding armature coils with voltage. As the brushes pass over the gaps in the commutator, the supplied electrical charge switches commutator segments, which switches the electrical polarity of the armature coils.
The voltage between brushes fluctuates in amplitude between zero and a maximum value, but is always maintains the same polarity. As mentioned earlier, the commutator is constructed in segments, which are insulated from each other. As the brushes pass from one segment to the other, there is an instant where the brushes contact both segments at the same time. This is referred to as the neutral plane, and at this point, the induced voltage is zero. Otherwise, the brushes would short the ends of the coil together and cause sparking due to high voltage.
Brushless DC motors also require commutation, but for brushless designs, commutation is carried out electronically, via an encoder or Hall effect sensors that monitor the position of the rotor to determine when and how to energize the coils. You must be logged in to post a comment. Leave a Reply Cancel reply You must be logged in to post a comment.