This time i want share some information about two common method that used around the world for braking electric motor for any application,equipment or machinery system.
For this two method for braking electric motor system are d.c injection and plugging is suitable application to stop a drive efficiently depend on our system and design.
Braking system for electric motor
1) Braking by d.c. injection.
In this method,it disconnected the a.c and d.c supply to the stator winding to created torque for braked the drive or electric motor.
The impact from power supply disconnected is it created magnetic static field in to the rotor area and current will generated in the rotor winding to produces high breaking torque.This method also use in a shut wound d.c motor.
Basically a d.c power supply need to provide for this method and it ca get from build in rectifier system in the controlled system.
To stop the driven or electric motor,we need to push in the stop button and it made the contactor is open and the d.c contactor is close position.It made the stator connected with rectifier to receive the d.c power supply.
After that the motor is rapidly brought to rest.It controlled by a timer delay relay to set the varying period for application of d.c supply to load the motor stator and d.c contactor de-energize.Please refer to diagram below.
2) Braking by reversal (plugging).
These method is common used for rapid braking of a.c. and d.c. motors.To stop the drive,the braking controlled was reconnecting the winding to the supply to corresponding to reversed direction may of drive rotation either clock wise or anti-clock wise.
It must perform in quickly action controlled by magnetic contactor wit automatic control system.The controller must suitable with drive or electric application to ensure it can stop it when is needed.
When deceleration is completed and the motor stops, it will of course reverse unless the windings are disconnected.It not suitable for the normal starting gear required for an induction motor because it will damage the driven system.The motor requirement and drive system must be high consideration before applied this braking method.