The working principle is based on electromagnetic induction and the creation of a Rotating Magnetic Field (RMF):
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1AC Supply to Stator: Alternating current is supplied to the stator windings, generating a continuously rotating magnetic field.
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2Electromagnetic Induction: The rotating field cuts through rotor conductors, inducing a current in the rotor by Faraday's Law.
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3Torque Generation: The induced rotor current creates its own magnetic field, interacting with the stator field to produce electromagnetic torque.
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4Mechanical Output: The torque causes the rotor to spin, driving the shaft and delivering mechanical energy to the connected load.
Stator
The stationary outer part containing three-phase windings placed 120° apart. Produces the rotating magnetic field when energised by AC supply.
Rotor
The inner rotating part mounted on the shaft. Follows the stator's rotating magnetic field and converts electromagnetic torque into mechanical rotation.
Air Gap
A small physical gap between stator and rotor that allows magnetic flux to efficiently link both components without mechanical contact.
Shaft and Bearings
The shaft transmits rotational mechanical energy to the load. Bearings support the shaft and enable smooth, low-friction rotation.
Induction Motor (Asynchronous)
The most common type. Rotor speed is slightly less than the stator's rotating field speed (slip). Available in single-phase and three-phase. Simple, robust, low maintenance.
Synchronous Motor
Runs at exactly the same speed as the rotating magnetic field with no slip. Requires external rotor excitation. Used where constant speed is critical.
Single-Phase Induction Motor
Powered by single-phase AC supply. Common in household appliances — fans, refrigerators, washing machines. Requires starting mechanisms such as capacitors.
Three-Phase Induction Motor
Powered by three-phase AC supply. Self-starting, highly efficient, and used in heavy industrial applications — compressors, conveyors, cranes, and HVAC systems.
- Industrial pumps and water treatment plants
- HVAC and air conditioning systems
- Conveyor belts and material handling
- Compressors and blowers
- Household appliances — washing machines, fans, refrigerators
- Electric vehicles and elevators
- Power tools — drills, grinders, saws
- Food and beverage processing equipment
| Parameter | AC Motor | DC Motor |
|---|---|---|
| Power Source | Alternating Current (AC) | Direct Current (DC) |
| Construction | Simple, fewer parts | More complex (brushes, commutator) |
| Maintenance | Low — no brushes | Higher — brushes wear out |
| Speed Control | Via Variable Frequency Drive (VFD) | Easier direct control |
| Cost | Lower initial cost | Higher initial cost |
| Best For | Industrial and commercial use | Precise speed and torque control |
AC Drives and VFDs
Control and optimise AC motor speed and torque with our range of variable frequency drives.
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Direct-on-line and soft starters for safe and controlled starting of AC motors.
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Electrically controlled switches for starting and stopping AC motors safely in circuits.
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Protect AC motors from overheating and overload conditions with thermal and electronic relays.
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Circuit breakers and protection devices designed specifically for motor applications.
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MCBs and MCCBs for overcurrent and short-circuit protection in motor circuits.
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