We don’t often like technical mumbo jumbo, however there is a lot of money being made in technology. Specifically electric motors. These little electric motors are in nearly everything we experience day to day! Here is a cool insight into how these wonderful inventions works. This article was provided by our friends at Bay Motor Products, a Electric Motor Manufacturer.
Ac Electric Motors are Big Business
Today the AC motors have turned out to be the typical industrial motor being used anywhere in the world. Having the key advantages of reliable operation, low cost, simple design, easily found replacements and having a variety of mounting styles, AC motors have become very popular and are widely used. They are designed such that it has a series of winding in the exterior and a rotating section inside. The changing electrical field caused by the AC line voltage will make the rotor turn around the axis of the motor. Here the speed of the motor will depend on the fixed number of the winding, frequency of the AC line voltage and the torque loading on the motor. An extensive use of these AC electrical motors has made the search for replacements and spares an easy task.
An electric motor is simply about magnets and magnetism. The motor utilizes the magnets for the purpose of creating motion.
Take for example a simple toy magnet. There are two opposites which can attract and repel. So if there is one end which is labeled ‘North’ and the other ‘south,’ then the north will attract the south. The north end will repel another north end, and the south end will also resist the other south end. The same principle is applied inside the motor. There are continuous attracting and repelling forces which will create a rotation motion.
The rotor of an electric motor is an electromagnet. It is made of copper wire wound in around a soft iron core. The magnetic field is a permanent magnet, but two magnets are fitted inside the casing of steel.
Larger motors and generators’ electromagnets are also the field magnets which are today being used in cars.
Small electric motors
Inside a small electric motor are two small permanent magnets inside of a casing, two brushes which are housed and a winding wire around metal lamination or shafts with winding wire wound on them, this is known as the armature or the rotor.
There are three poles on the rotor which causes it to move better. If there are two poles, the electromagnet is the balancing point and between the two poles is a field magnet. For three poles the motor can start turning from any point.
Now, each time the commutator (a switch that will reverse the direction of the current between the rotor and the external circuit) changes the direction of the field in a two-pole type motor, it will short out the battery for a little bit. This will waste the battery and drain it of its power. The three poles will fix this problem for it will only shift the direction when the repulsion is at its strongest point.
Now, there are motors with varying number of poles, but this depends on the size of the motor and how it is being used. There are some who use very rare but powerful magnets which can boost the power a lot; however, this makes the motor very expensive. Today, the commutator is not as well utilized as electronics are now commonly used which will rid the motor from sparking and constant servicing.
In short, an electric motor utilizes electrical energy to produce a mechanical energy with the use of magnets and magnetic fields.
In the makings of an electric motor, there are two types of power sources. Most electric motors run on the alternating current which causes the alternating of poles and continuous spinning of electromagnetic coils. Batteries power electric motors running on direct current. To produce the alternating poles effect, there is an additional part in each motor to simulate the alternating direction of the current into the electromagnet. If a device requires a fair amount of movement, it is powered by alternating current. Fans, blenders, and trains fall into this category. Direct current is usually sufficient for lesser-powered motors such as notebook fans and hard disks, hand-held vacuum cleaners, and electric toothbrushes.
Shaded Pole Motors
Shaded Pole Motors are the original type of Ac single phase induction motor. A single phase motor is run from a power source with a single distribution of alternating current electric power. This means that in the power supply, all of the voltages vary in unison. The typical characteristics of electric motors of single phase are that the current produces a pulsating rather than a rotating magnetic field and that an additional circuit is needed for starting this motion.
The currents in single phase motors reach their peak values simultaneously, making one phase.
There are many different types of motors available, each category defined by the method used to start the mechanism. These types include the split phase motor, capacitor start/ induction run, permanent slip capacitor and the capacitor start/capacitor run.
The split phase motor also referred to as induction start/ induction run, is one of the simplest electric motor designs. It features a starter winding and the main winding, with the starter winding having a smaller gage wire and fewer turnings. This difference creates resistance in the motor and causes a rotating field. The main winding is heavier and maintains the running of the motor.
The capacitor start/ induction run type is a single phase motor that features a capacitor in the start winding which creates increased starting torque. A switch mechanism disconnects the start winding and capacitor when the speed reaches about 75% of its rated speed. The capacitor start motor also features a lower starting current, making it suitable for a broad range of applications.
The permanent split capacitor features a run capacitor which is connected permanently to the auxiliary start winding. Permanent split capacitors have low starting torque and low starting currents. Unlike many single phase electric motors, permanent split capacitors do not require any additional starting mechanisms.
These motors are used for low power applications where it would be inefficient to use more high-powered devices. Many single-phase motors are ideal for applications with low inertia while others are engineered to meet high starting torque requirements.
Here are the advantages of the single phase model:
The size of these motors makes them perfect for use in smaller applications, such as fans, pumps, refrigerators, portable drills, and compressors.
There are several types of motors to choose from, including split-phase, capacitor-start, shaded-pole and wound rotor. Each of these types has its advantages and disadvantages.
These engines are far less expensive to manufacture than other types and, on top of these, they are also very efficient. This makes them an excellent choice for many applications.
The mechanics behind these motors is fairly simple, meaning that repairs and maintenance can be completed far easier and faster than they can on other types.