Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Commonly used motor in industries is
Synchronous motor
DC motor
Induction motor
Stepper motor
Induction motor
The three-phase induction motor is the most widely used motor in industrial applications due to its rugged construction, high reliability, and cost-effectiveness. It operates on the principle of electromagnetic induction without requiring brushes or external excitation for the rotor.
The three-phase induction motor is the most widely used motor in industrial applications due to its rugged construction, high reliability, and cost-effectiveness. It operates on the principle of electromagnetic induction without requiring brushes or external excitation for the rotor.
NsтАЛ=P120fтАЛ тАФ Synchronous speed formula
s=NsтАЛNsтАЛтИТNrтАЛтАЛ тАФ Slip calculation formula
When a three-phase supply is applied to the stator windings, it creates a Rotating Magnetic Field (RMF). This RMF induces an EMF in the rotor conductors (Faraday's Law), causing rotor currents to flow. The interaction between the RMF and the rotor current generates a torque, forcing the rotor to rotate in the direction of the RMF at a speed slightly less than the synchronous speed (slip).
Does not require a separate DC supply for the rotor.
Self-starting capability (in three-phase versions).
Speed regulation is inherently determined by the load.
Simple and robust construction
Low maintenance and high reliability
Cost-effective compared to DC or synchronous motors
Speed control is complex and expensive (requires VFDs)
Poor starting torque compared to DC series motors
Draws high inrush current at startup
Centrifugal pumps and fans
Conveyor belts and compressors
Machine tools and industrial mixers
Synchronous motors are used where constant speed is critical, regardless of load.
DC motors provide excellent speed control but require brush maintenance.
Stepper motors are used for precise positioning rather than continuous industrial driving.
C is correct тАФ The induction motor is the industry standard due to its simplicity, durability, and lack of requirement for additional excitation systems.
Always remember that induction motors run at 'slip speed', never exactly at 'synchronous speed', otherwise the torque would drop to zero.