Skip to main content

DYNAMIC BRAKING

                             DYNAMIC BRAKING 

DYNAMIC BRAKING (OR) RHEOSTATIC BRAKING :
                        Dynamic braking is also called rheostatic braking. In this method of braking, a motor is disconnected from the supply and operated as a generator driven by the kinetic energy of the rotor. The kinetic energy of rotation is converted into electric energy, which is dissipated in the external resistance connected across the motor at the braking instant. The advantage of this type of braking is that no energy is required from the supply to brake the motor. This method of braking can be applied to brake the D.C motors, synchronous motors and induction motors.

DYNAMIC BRAKING TO INDUCTION MOTOR :
                     
                                           fig 1.1
               In 3 phase squirrel cage induction motor, the stator is disconnected from the A.C supply mains and D.C supply is given to the stator winding as shown in fig. 1.1(b). A steady flux is produced. The short circuited rotor cuts this steady flux and an emf is induced in these conductors. This provides the necessary braking effect. In the case of 3 phase slip ring induction motor the braking torque is controlled by adding the resistance in the rotor circuit. 

DYNAMIC BRAKING TO SYNCHRONOUS MOTOR :
                          In synchronous motor, the D.C excitation is maintained and the stator is disconnected from A.C supply. Then the stator is connected across three resistance in star or delta.Now the machine operates as an alternator and the kinetic energy is dissipated in the resistance and braking will occur.

           MP3 VERSION IN #TAMIL CLICK MY LOGO                                                        GIVEN ABOVE


#TAMIL VERSION OF VIDEO : https://youtu.be/BzXCyXn7YlM


T     H      A      N        K             Y        O        U           B       Y    

                                          R      D      K
                                                   &
                             T            E             A             M



Comments

Post a Comment

Popular posts from this blog

SELECTION OF MOTORS FOR DIFFERENT DUTY CYCLES

   SELECTION OF MOTORS FOR DIFFERENT DUTY CYCLES : 1. Continuous duty cycle :                          It denotes the motor operation at a constant load torque to reach steady state temperature. The load time and. temperature time graph are shown in fig 1.1 EXAMPLES :               Paper mill drives compressors, conveyers, centrifugal pumps and fans                                              fig. 1.1 2. Short time duty :                   It denotes the operation of motor at constant load for short period followed by rest to cool down to the original starting temperature. Short time duty timings are generally 10, 30, 60 and 90 minutes. The load time and the temperature time graph are shown in fig 1.2  EXAMPLES :               Crane drivers, drives for household appliances, sluice gate drives, valve drives and machine tool drives                                              fig 1.2 4. Intermittent period duty with starting :
Post a Comment
Read more

single bus bar and single busbar with sectionalisation

                                            BUS BAR 1.                               SINGLE BUS BAR                 In this way, only one set bus - bar is attached to the entire generating station.  All transformers, generators and feeders are connected to this single bus - bar.  Generators are connected to the bus - bar via isolator and circuit breakers.  Similarly to incoming and outgoing feeders via isolator and circuit breakers are attached with bus bar. This system will suitable for both A.C and D.C ADVANTAGES:                         1.  Only one circuit breaker is required for each                              outgoing circuit.  So it's simple and cost effective.              2.  Since there are no transfer circuit breakers and                        disconnectors, the operation is simple              3.  The number of circuit breakers required is low.                        So the cost of maintenance is low.              4.  The potentia
Post a Comment
Read more

ELECTRICAL TRACTION

                              ELECTRICAL TRACTION : ELECTRIC TRACTION :            Electric traction means a locomotion in which the driving force is derived from electric motors.  There are many advantages of electric traction over other forms of jocomotion in the current days of traction in any country of development.  In fact, it is a fast-paced, safest and economical way of transporting and transporting goods to the modern day. In this type of drive the locomotive is equiped with a d.c series motor or ac series motor or three phase induction motor. The electric energy is directly fed into the motor and torque developed by the propelling the train.                             TRACTION SYSTEMS : The most commonly used traction methods are as follows. 1.  Steam engine drive  2. Internal combustion engine drive  3. Battery electric drive  4. Internal combustion engine electric drive  5. Electric drive               IDEAL TRACTION SYSTEM OF REQUIREMENTS : 1.The u
Post a Comment
Read more