Motor
A motor is an apparatus that converts an energy source into mechanical energy in order to generate motion.
Electrical energy is transformed into mechanical energy by electric motors.
A motor that is linked to the power source could power the generator.
A motor is an apparatus that converts an energy source into mechanical energy in order to generate motion.
Electric Motor Types: The Definitive Guide
Electric motors are used in a wide range of applications, including sophisticated aerospace applications, everyday domestic products, and many forms of transportation. We present you a guide in this article to help you better understand your alternatives.
Electric Motors vs. Generators
Although they have different purposes, electric motors and generators are both electromagnetic devices with an armature winding, or rotor, that revolves inside a field winding, or stator. Motors transform electrical energy into mechanical energy, and generators transform mechanical energy into electrical energy.
Two Types of Electric Motors
In electric motors, the armature winding uses the field windings electric current to create a fixed magnetic field, which turns the motor shaft. The distinctive characteristics of each type of electric motor, including voltage and application requirements, are what set them apart from one another. Electric motors come in a minimum of a dozen varieties, however they can be broadly categorized as either direct current (DC) or alternating current (AC). There are further differences within each of these categories based on how the windings in AC and DC motors interact with one another to generate mechanical force.
DC Motors
Brushed Motors
Four major parts make up brushed motors:
Stator
Rotor or Armature
Brushes
Commutator
The four primary types of brushed motors are as follows:
Series Motors:
Their field currents are the same because the stator and rotor are in series or identical. Features: excellent low speed torque, restricted high speed torque, utilized in cranes and winches.
Shunt Motors:
The motor current is equal to the total of the two currents since the field coil and rotor are parallel (shunt). Features: high/consistent torque at low speeds, great speed control, utilized in automotive and industrial applications.
Cumulative Compound Motors:
The motor current is equal to the total of the series field and shunt field currents in this type, which combines elements of the shunt and series kinds. Features: combines the advantages of series and shunt motors; utilized in automotive and industrial applications.
PMDC Motors (Permanent Magnet):
PMDC motors, the most popular kind of brushed electric motor, generate the stator field using permanent magnets. Characteristics: less expensive to build, good low end torque, limited high end torque, utilized in the commercial production of toys and appliances.
Brushless
Brushless motors are those without brushes or a commutator. Rather, the coils are on the stator, and the rotor is a permanent magnet. Brushless motors regulate the magnetic fields from the stator by varying the amount and direction of current flowing through the coils, as opposed to regulating the magnetic fields on the rotor. The efficiency of brushless motors is one of their key benefits since it enables better control and torque production in a smaller unit.
AC Motors
The rotor speed in relation to the stator speed is the primary indicator of synchronous or asynchronous motor type within the AC motor classification. In a synchronous motor, the rotor and stator rotate at the same speed; in an asynchronous motor, however, the rotor spins at a slower pace than its synchronous speed. Furthermore, asynchronous or induction motors have slip and do not require a secondary power supply, but synchronous motors have zero slip and do.
Synchronous Motor
A synchronous motor has two electrical inputs, making it a twice stimulated machine. A single input, often three-phase AC, powers the stator winding of a typical three-phase synchronous motor, resulting in the production of three-phase spinning magnetic flux. Usually, a DC power source is used to activate or start the rotor. The motor becomes synchronous when the rotor and stator fields lock.
Asynchronous (Induction)
Asynchronous motors can start by giving power to the stator without powering the rotor, thanks to induction, which is not the case with synchronous motors. There are two types of induction motor designs: winding and squirrel-cage. Asynchronous induction motors include, for
instance:
Capacitor Start Induction Run Motors:
This is a capacitor-started, single-phase wound motor with a cage rotor and two stator windings. Compressors and pumps in refrigerators and air conditioning systems that restart and stop frequently are among their uses.
Squirrel Cage Induction Motors:
This motor features a highly conductive steel lamination squirrel-cage rotor, and a three-phase supply generates a magnetic field in the stator winding. These include industrial drives, huge blowers and fans, machine tools, lathes, centrifugal pumps, and other turning equipment. They are also inexpensive, low-maintenance, and highly efficient motors.
Double Squirrel Cage Motors:
These motors solve the problem of squirrel cage motors having low starting torque. Their design maintains overall efficiency while enhancing startup torque by balancing the reactance to resistance ratio between an inner and outer cage.
Electric Motor Identification
Meeting the requirements of four qualities is necessary in order to choose the motor that is most appropriate for a certain application:
Power and Velocity
Drivetrain Frame
Needs for Voltage
Covers & Placement of Mounting
Except for enclosure information, vital details about these features are listed on a metal nameplate that is fastened to the motor.
Electric Motor Horsepower & Speed Rating
The rotational speed rating (RPM) and horsepower rating should both be in line with the load specifications for the installed application. There are various classifications of motor horsepower: big motors (100 HP to 50,000 HP), integral horsepower motors (1 HP to 400 HP), and fractional motors (1/20th HP to 1 HP). There are three different RPM ratings: 2 pole (3600 RPM), 4 pole (1800 RPM), and 6 pole (1200 RPM).
Electric Motor Frame
The performance values of a motor, particularly its horsepower rating, are not indicated by the size of its frame. The National Electrical Manufacturers Association (NEMA) created frame numbers whose digits corresponded to mounting sizes, or the distance between the center of the shaft and the center bottom of the mount. Larger horsepower motors can be manufactured into fractional motors, which are typically identified by two-digit labels.
Voltage Requirements
The requirements for voltage include voltage, frequency, and phase. The majority of three-phase motors in North America and Europe have dual voltage displays, such as 230/460. Electric motors typically run at 60 Hz, while in Europe, 50 Hz motors are more prevalent. This fluctuation in hertz means that the motor will run at a speed that is 5/6 of its typical RPM. Phase, which indicates the type of supply needed, such as three-phase, single-phase, or DC, is the last piece of information supplied with a motor's voltage requirements.
Enclosures and Mounting Positions
The installation environment of the motor determines the enclosure information. Open and enclosed motors are the two primary types of enclosures.
Open Motors
Since open motor enclosures allow air circulation via the windings, open motor applications include relatively clean and dry indoor environments.
Enclosed Motors
These kinds prevent the motor's exterior and interior from exchanging free air. Enclosed motor types can be further distinguished by differences in cooling characteristics and enclosure air-tightness, such as:
Totally Enclosed Fan Cooled (TEFC)
Totally Enclosed Non-Ventilated (TENV)
Totally Enclosed Air Over (TEAO)
Totally Enclosed Wash Down (TEWD)
Explosion-Proof Enclosures (EXPL)
Hazardous Location (HAZ)
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