Motors can run off of direct current DC or alternating current AC , and both have their benefits and drawbacks. For the purpose of this article a DC motor will be analyzed, to read about AC motors, click here. The main parts of a DC motor include: [3]. Figure 3: A basic setup of a DC motor. Figure 4: An animation of the motor in action. The commutator rotates in order for the rotor to spin continuously. Usually 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 what it needs to do. Now, we're going to look at the AC motor. AC motors use alternating current instead of direct current.
It shares many parts with a DC motor, and it still relies on electromagnetism and flipping magnetic fields to generate mechanical power. The winding of the stator in an AC motor kind of does the job of the rotor of a DC motor. In this case, it's a ring of electromagnets that are paired up and energized in sequence, which creates the rotating magnetic field.
You'll remember that the rotor in a DC motor is hooked up to the battery. But the rotor in an AC motor does not have any direct connection to a power source. Nor does it have brushes.
Instead, it often uses something called a squirrel cage. You read that right. The squirrel cage in an AC motor is a set of rotor bars connected to two rings, one at either end.
It's kind of like something a caged mouse or squirrel would run inside. The squirrel cage rotor goes inside the stator. When AC power is sent through the stator, it creates an electromagnetic field. The bars in the squirrel cage rotor are conductors, so they respond to the flipping of the stator's poles.
That's how the rotor rotates, which creates its own magnetic field. The key to an AC induction motor, where the field of the rotor is induced by the field of the stator, is that the rotor is always trying to catch up. It's always looking for stasis, so it's rotating to find that steady state. But the electromagnetic field produced by the stator using AC power is always going to be a little faster than the rotor's field.
The spin of the rotor is creating the torque needed to create mechanical power to turn the wheels of a car or the whirr of a fan. Some AC motors use a wound rotor, which is wrapped with wire instead of being a squirrel cage. The squirrel cage kind is more common, though. In either case, there's only one moving part in an AC motor, which means there are fewer things that need replacing or maintenance.
Look around your house and you will find that it is filled with electric motors. Since our homes use AC power, most of these gadgets have AC motors. DC motors are more likely to be found in things that use batteries.
Starting in the kitchen, there are motors in:. You might be wondering about electric cars, which use AC motors but run on batteries, which supply DC power. The answer is easy: Electric vehicles have an extra part, called a converter, that converts the DC power from the batteries to AC power that the motor can use. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots.
Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Solid State Electronics. How Electric Motors Work. Electric motors are everywhere. Inside an Electric Motor " ". You might be surprised to find out just how much work is done by electric motors. You flip the magnetic field by changing the direction of the electrons.
Electricity moving through a wire creates a circular magnetic field with the wire as the source and center of the rotation. When you add current, the stator and armature form a stable magnetic field and an electromagnet that is pushed or rotated within that field, respectively.
The basic motor runs on DC, or direct current, but other motors can run on AC, or alternating current. Batteries produce direct current, while the outlets in your home supply alternating.
They move the motor through a phenomenon known as induction. Some DC motors are also brushless and instead use a switch that changes the polarity of the magnetic field to keep the motor running. Universal motors are induction motors that can use either source of power. Now that you have the basic parts and principles, you can play with the concept at home. Make a coil from lower gauge copper wire and poke each end through an aluminum can to suspend it.
Place a small, strong magnet on either side of the suspended coil to create a magnetic field. If you attach a battery to both cans using alligator clips, your coil will become an electromagnet and the copper wire rotor you created should start to spin. Based in Wenatchee, Wash. She has written peer-reviewed articles in the "Journal of Wildlife Management," policy documents,and educational materials.
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