Electric motor Definition and 222 Threads

An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy.
Electric motors may be classified by considerations such as power source type, internal construction, application and type of motion output. In addition to AC versus DC types, motors may be brushed or brushless, may be of various phase (see single-phase, two-phase, or three-phase), and may be either air-cooled or liquid-cooled. General-purpose motors with standard dimensions and characteristics provide convenient mechanical power for industrial use. The largest electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors are found in industrial fans, blowers and pumps, machine tools, household appliances, power tools and disk drives. Small motors may be found in electric watches. In certain applications, such as in regenerative braking with traction motors, electric motors can be used in reverse as generators to recover energy that might otherwise be lost as heat and friction.
Electric motors produce linear or rotary force (torque) intended to propel some external mechanism, such as a fan or an elevator. An electric motor is generally designed for continuous rotation, or for linear movement over a significant distance compared to its size. Magnetic solenoids are also transducers that convert electrical power to mechanical motion, but can produce motion over only a limited distance.
Electric motors are much more efficient than the other prime mover used in industry and transportation, the internal combustion engine (ICE); electric motors are typically over 95% efficient while ICEs are well below 50%. They are also lightweight, physically smaller, are mechanically simpler and cheaper to build, can provide instant and consistent torque at any speed, can run on electricity generated by renewable sources and do not exhaust carbon into the atmosphere. For these reasons electric motors are replacing internal combustion in transportation and industry, although their use in vehicles is currently limited by the high cost and weight of batteries that can give sufficient range between charges.

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  1. ?

    Having trouble with circuit to adjust speed of electric motor

    I'm building a device powered by an electric motor, it needs to travel much slower than the RPM output the motor has... I've gotten into some trouble with my circuit trying slow the thing down, hoping for some suggestions... at the moment my circuit goes: battery, switch, potentiometer...
  2. A

    CVT transmission for an electric motor

    Hey everyone, i am trying to design a small and lightweight cvt (continiously variable transmission) for an electric car that can either be on or off, no variable speeds from the motor. I am having trouble representing the math of the transmission. I have to have the car complete a race of 312...
  3. M

    New Electric Motor: How to Hook Up & Test Power Supply

    I just bought a new 300 watt, 24 volt DC electric motor which I plan to use in a couple projects I am working on. Here is a picture of it, http://www.electricscooterparts.com/ebaypics/COKEKMa.jpg The problem comes now that I want to turn the motor on and use it (something I guess I should...
  4. F

    Electric motor contest - suggestions?

    there is a contest to build an electric motor for which we can get some bonus points on the final in my E&M class. they give us a very limited kit and we can only use what comes in the kit which is a couple pieces of thick poster board, 6 feet of insulated wire, a couple paper clips, a couple...
  5. S

    Seeking Advice on Increasing Electric Motor Power Output

    Hi there. Im afraid i know very little about electrical engineering:confused: , hence why I am here, but any help / direction / suggested reading would be much appreciated! Like i say, sorry if this is a completely stupid question:blushing: , but if you don't ask you don't get right? and who...
  6. P

    Calculating Water Output of a 2.0 hp Electric Motor

    A 2.0 hp electric motor on a water well pumps water from 10 m below the surface. The density of water is 1.0 kg per liter. How many liters of water does the motor pump in 1 hr? im not sure what equation to use on this problem, so if anyone could let me know that would be good thanks!
  7. M

    Finding the Weight and Center of Gravity of a Heavy Electric Motor

    Two people carry a heavy electric motor by placing it on a light board of length 2.50 m. One person lifts at one end with a force of 400 N, and the other lifts the opposite end with a force of 560 N. a) What is the weight of the motor? b) Where along the board is its center of gravity...
  8. A

    How Can You Build a DC Electric Motor with Coils and a Magnet?

    hey, i have to create an electric motor using a DC source and using coils wrapped using the left hand rule (not bar magnets). Anyone know an easy way to go about this? i guess it has to be something like this. http://fly.hiwaay.net/~palmer/motor1.gif it must be usable with a battery and...
  9. K

    Electric motor + 12 volt battery ?

    I admit it, I am a complete and utter noob when it comes to electrical components. I need help. I am trying to run an electrical motor on a regular 12 volt car battery. Can this even work? If so, how much money and work needs to be done? This is for a little..."project". If anyone can...
  10. M

    How Does a Split Ring Commutator Enhance Motor Speed?

    hey there if anyone can help i'd be very grateful. i have a science project :cry: and i have to construct a working electric motor. i have to make it spin as fast as possible so i did some research and found out about something called a split ring commutator. i still don't understand what it...
  11. C

    How does beakman's electric motor work?

    In class we made a beakman's electric motor using wire, a battery, and a magnet. I don't understand how the motor works though. Can someone explain it to me? I think it has something to do with the magnetic poles, but I am not sure. This site: fly.hiwaay.net/~palmer/motor.html has a diagram...
  12. B

    Control Electric Motor Velocity on a Budget

    Hello, Can anyone tell me what is the simpliest and cheapest method to control of velocity of an electric motor? or what kind of motor to use to reach such a control?
  13. M

    Calculating Horsepower for Electric Motor Pressurization

    Please forgive what I'm sure is a dumb question, but I'm stumped. Is there a way to determine the amount of horsepower (from an electric motor for instance) that is req'd to pressurize a tank of a known volume to a specific pressure? In other words if an electric motor is used to compress...
  14. M

    Find the power an electric motor

    hi, i need just a formula to go ahead with this. I am given two masses, m1 of man, and m2 of his bike. he is going up a hill with slope (sqroot3/3) and velocity (v). Now I need to find the power an electric motor would need to have for the man to b able to ride his bike up without pedalling...
  15. H

    Understanding the Star Winding in 6-12 Volt Generators

    The armature of an electric motor, (the inside coils) are made from copper and have extremely low resistance. When you connect the motor to a voltage supply and supply some current to the motor, even though the resistance is low, the current may be as little as 2 or 3 Amps. Where does the...
  16. A

    Fix Electric Motor on Dryer - Get Help Now!

    im working on my dryer motor. its just an electric motor. i turn it on and it seems like the whole motor box is trying to turn instead of just the gear like its stuck or something. does anyone have clue. thanks.
  17. P

    Building an Electric Motor: Tips and Guidelines for 11th Grade Physics Class

    I've been trying to build an electric motor for my 11th grade physics class and I'm having some problem. I'm trying to stay away from using a reed switch because my teacher hinted at a better grade for motors using a split-ring commutator (and because I couldn't find a reed switch anywhere)...
  18. F

    Is the Efficiency of This Electric Motor Too Good to be True?

    I think this is a hoax. http://www.japan.com/technology/index.php they power out > power in.
  19. C

    What are the Physics Behind the Equilibrium Motor Concept?

    Hello. Please, take a read to www.geocities.com/k_pullo/PM3.htm It's an study based on the Butch Lafonte's equilibrium motor. Please, forget the claims, and take a look under classical physical principles. Basically, on normal motors we use the electric energy to impulse the...
  20. Ivan Seeking

    Experts please: Review of Pulsed Plasma Electric Motor Patent

    This guy is effectively asking for donations on EBay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2193742726&category=14431 This is the patent...
  21. M

    Is this Pulsed Plasma Electric Motor on eBay a legitimate invention or a scam?

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2193742726&category=14431 I was going to post this in engineering, but I think this is more suitable. Can someone take a look at this page real quick? It sounds pretty cool, like something from star trek, so I'm pretty sure it needs to be...
  22. K

    How Does Partial Wire Insulation Affect Beakman's Electric Motor Functionality?

    http://fly.hiwaay.net/~palmer/motor.html In step 2, it says Why we should remove the insulation from one side of the wire while to sand off the insulation from the top half of the other end of the wire? What if we remove all the insulation from both ends of the wire? And what happen if...
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