Ac Motor Introduction operation and construction

  AC Motor

 An electric motor transfers electrical energy into mechanical energy. It serves as the link between a building's electrical and mechanical systems. 

Any electrical system needs electric motors as a crucial component. They use around 64% of the electricity produced in factories, workplaces, and residences. 

 

Principle of Motor Operation

A magnetic field will be created across a wire loop with electrical current flowing through it. An additional magnet's field will cause this loop to rotate, creating a mechanically actionable force (torque). 

 Basic Components of an AC Motor
Basic AC Motor Parts:

The following are the fundamental components of AC motors:

• Enclosure. 

• Stator. 

• Rotor. 

• Bearings. 

• Cable Box. 

• Face Bolt. 

Important Terms

Enclosure

A frame, a yoke, and two end brackets, sometimes called bearing housings, comprise the enclosure. The enclosure of a motor not only keeps the motor's parts together and. The type of enclosure determines the level of protection.

Drip-proof (ODP) 

The motor can receive cooling air through open enclosures. The open leak proof (ODP) enclosure is a type of open enclosure. This cage contains vents that let air move through it. 

 Complete enclosure an enclosure that is entirely sealed off and unventilated i.e. Fan-Cooled Enclosure 

An explosion-proof enclosure. 

The air around the motor includes corrosive or toxic substances that might destroy the motor's internal components. TENV, motor enclosure restricts the air that can enter the motor but is not completely airtight. The majority of TENV motors have very little power. 

 TEFC/ Fully Enclosed Fan-Cooled Enclosure 

An external fan is positioned opposite the drive end of a fully enclosed fan-cooled (TEFC) motor comparable to a TENV motor. To further cool the motor, the fan blows airflow across its surface. 

An explosion-proof enclosure (XP) 

The chemical processing industry and the mining industry to protect people, machines, and the environment, motors used in these applications must adhere to the strictest safety regulations

An XP motor resembles a TEFC motor in appearance, although the majority of XP enclosures are made of cast iron.

Stator

There are two basic components to the motor stator: 

Core Stator

The electromagnetic circuit of the motor's stator is stationary. An electrical circuit that functions as an electromagnet is the stator. Laminations, or several thin metal sheets, make up the stator core. Unlike using a solid core, laminations help minimize energy losses.

A hollow cylinder is created by stacking stator laminations. The stator core's slots are filled with coils of insulated wire. The stator windings have wiring, so they constantly access the electrical current supply .When electricity is supplied, each collection of coils and the steel core they surround becomes an electromagnet. 

Rotor 

The electromagnetic circuit of the motor's rotor rotates. An opposition magnetic field is induced onto the rotor by the stator's magnetic field, which causes the rotor to "push" away from the stator's magnetic field. The rotor is supported and may rotate thanks to bearings positioned on the shaft. The following characteristics are used to determine the bearing arrangement:

• Capacity to carry loads both axially and radially.

• Overly long and fast.

• Rotational rate.

Bearings

The bearing size that will be used is originally decided on according to its load-carrying capability.

Types of Bearings: Numerous varieties of bearings are available, each with unique qualities and purposes. These varieties include the following:

1. Deep groove ball bearings 

Deep groove ball bearings, can support both thrust and radial stresses. They work well at high speeds due to their low frictional torque. 

2. Bearings for cylindrical rollers

They are needed to withstand severe radial loads, those roller bearings are employed. Because the roller is a cylinder, the connection between its inner and outer races is a line. 

3. Raceways in both the outer and inner rings 

Allows the bearing to accommodate a larger range of radial and axial loads. Indicates that they can accommodate mixed loads, such as those that act radially and axially simultaneously in vertical machines, without causing any problems.

4. Spherical roller thrust 

Within Spherical thrust roller bearings, a load travels from 1 raceway to another at an angle relative to the bearing's center. In addition to distributing tiny radial loads, they can accommodate significant axial loads. 

5. Bearings with Sleeves 

With no moving parts, sleeve bearings rely on a thin layer of oil to decrease friction and permit the motor shafts to rotate smoothly. 

A pedestal is used to support the foot-mounted sleeve bearings. Either the pedestal can be placed separately, or it can be integrated into the stator frame

Box Conduit

Point of electrical power supply to the stator windings of the motor.

Sixth Eye Bolt 

Iris Bolt is used as a means of lifting large motors