What is an Electric motor?
If you’re sitting in a bedroom, you’ll find motors in hair dryers and many toys; in the bathroom, they’re in extractor fans, and electric shavers; in the kitchen, motors are in just about every appliance from clothes washing machines dishwashers to coffee grinders, microwaves, and electric can openers. Aside from the Electrical Supplier near you, The first electric motors were invented by Michael Faraday back in 1821. He was working on his famous “electromagnetic” experiments when he noticed something strange happening whenever he passed current through coils of wire. When he connected wires together, the resulting magnetic field caused nearby objects to move. In other words, electricity could make things go.
How does electromagnetism make a motor move?
Suppose you take a length of ordinary wire, make it into a big loop, and lay it between the poles of a powerful, permanent horseshoe magnet. Now if you connect the two ends of the wire to a battery, the wire will jump up briefly. Well, let’s start by looking at the simplest possible motor – one made entirely of iron.
There are four main parts of an Electric Motor:
- A coil of insulated copper wires
- An armature
- A shaft
This arrangement works as follows: As long as no current passes through the coils, they don’t create any magnetic fields. So nothing happens.
A Quick word about current
But if we want to turn this amazing scientific discovery into a more practical bit of technology to power our electric mowers and toothbrushes, we’ve got to take it a little bit further. The amount of charge passing through any given point in space depends upon three factors: 1.) How fast the charge passes; 2.) Where it goes; 3.) What kind of charge it is. If I’m standing next to my friend John Smith and he has a 100 amp fuse box wired for 120 volts AC, then his house lights may go off because too many people are using all those fuses. That doesn’t mean that everyone in town suddenly gets charged up with static electricity.
How an electric motor works in practice
The first step in understanding how a motor actually works is to understand what happens when you apply voltage across the terminals of a motor. When you do this, you’re applying a potential difference between those terminals. If you connect them with wires then they’ll be connected by some resistance, but if you put your hand over both terminals for a moment, you won’t feel any heat because the electrical energy passing through the connection is converted into thermal energy before reaching your body.
The most common type of universal motor uses two sets of windings wound around separate cores—one set of wires running along the length of the core, and another set winding across the width of the core. This arrangement provides four different poles with each turn of wire, allowing the motor to spin in either direction without reversing the polarity of the magnets. It’s not quite as efficient as a single-pole design, since there are twice as many turns per pole, but it does allow the motor to
Other kinds of electric motors
You can read more about this in our article on AC induction motors. This ingenious design is known as a linear motor, and you’ll find it in such things as factory machines and floating “maglev” railroads.
You can read more in our main article on hub motors Stepper motors, which turn around through precisely controlled angles, are a variation of brushless DC motors.
There are many other types of motors that don’t fit neatly into any of those categories. For example, there are synchronous motors, where the speed of rotation depends on how much electrical energy has been applied; stepper motors, where each step corresponds to a specific amount of electricity being passed through the windings; servo motors, used for precise positioning; and even some unusual ones, like the electromagnetic acoustic transducer, which uses sound waves to generate electricity!
Read our article about Electric Bulb.