04-05-2012, 03:01 PM
Three- Phase Cage Rotor Induction Motor Methods of Braking
05_presentation.ppt (Size: 194 KB / Downloads: 369)
Plug Braking
A centrifugal switch, speed sensing relay or timer used to prevent the motor from reversing.
Contactor C2 is for starting Contactor C3 is for stopping
Two phases are swapped over until motor stops.
DC Injection Braking
Power Schematic requires DC available at a lower voltage e.g. 50V
When required to stop, DC is connected to two of the phases
Rotor then runs faster than stator field causing a large braking torque in the rotor
Control circuit will be the same as for plug braking with timer, centrifugal switch or speed sensing relay