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
Which of the braking method is/are selected in the application like a hoist. train and electrical vehicle?
A) Plugging or Reverse Voltage Braking
B) Dynamic Braking
C) Regenerative Braking
D) All of these
Regenerative Braking
Regenerative braking is selected for application in hoists, trains, and electric vehicles because it allows the kinetic or potential energy of the load to be converted back into electrical energy and fed back into the supply system. In hoists (overhauling loads), electric trains (descending gradients), and electric vehicles (deceleration), the motor operates as a generator, recovering energy rather than wasting it as heat.
Regenerative braking is selected for application in hoists, trains, and electric vehicles because it allows the kinetic or potential energy of the load to be converted back into electrical energy and fed back into the supply system. In hoists (overhauling loads), electric trains (descending gradients), and electric vehicles (deceleration), the motor operates as a generator, recovering energy rather than wasting it as heat.
s=NsтАЛNsтАЛтИТNтАЛ тАФ Slip of Induction Machine (Negative during regenerative braking)
PgтАЛ=3I2тА▓2тАЛsR2тА▓тАЛтАЛ тАФ Air-gap power (Negative value indicates power feed back to stator)
Regenerative braking occurs when the rotor speed N exceeds the synchronous speed NsтАЛ (i.e., slip s<0). Under this condition, the induction machine acts as an induction generator, delivering active power back to the AC grid while drawing reactive power for excitation. In DC drives or inverter-fed AC drives, energy is pushed back to the DC bus/battery when the back-EMF exceeds the supply voltage.
Requires the driven load to supply mechanical energy (e.g., descending heavy loads in hoists or downhill vehicle motion).
Highest efficiency among all braking methods as energy is recovered rather than dissipated as heat.
Cannot bring the motor to a complete stop; it only works down to synchronous speed (or base speed control limit).
High energy efficiency due to power recovery back into grid/battery.
Reduces heat dissipation in motor and mechanical brake wear.
Ideal for frequent stop-and-go applications like electric vehicles and urban railways.
Cannot stop the machine completely; requires auxiliary mechanical or dynamic braking at zero speed.
Requires a supply line capable of accepting feedback power (or battery storage in EVs).
Inoperative if grid/line power fails unless energy storage systems are present.
Electric Traction (Electric Trains, Trams, Metro systems)
Electric and Hybrid Vehicles (EVs / HEVs)
Hoists, Lifts, Cranes, and Elevators during lowering operations
Option A (Plugging): Involves reversing phase sequence; causes maximum current and heat loss, inefficient for energy recovery.
Option B (Dynamic Braking): Dissipates kinetic energy as heat across an external resistor; useful for stopping but wastes power.
C is correct тАФ Regenerative braking converts kinetic/potential energy back into electrical energy during lowering of loads or deceleration, making it ideal for hoists, electric vehicles, and trains.
In competitive exams like GATE and ESE, remember that plugging gives the fastest braking torque but worst efficiency, dynamic braking gives controlled deceleration without grid dependence, and regenerative braking offers maximum efficiency (s<0).