Electric Motor Braking Methods

Mechanical brake

As soon as the motor is connected to the mains, the brake is released. If the brake is de-energized, the motor is braked.

Braking of electric drives - mechanical braking

Braking of electric drives - mechanical braking

Advantage: Very fast braking
Disadvantage: Wear


Countercurrent braking of induction motors

Countercurrent braking can be achieved by reversing the connections of the motor so that it tries to start in the reverse sense of rotation (by switching two supply lines).

Countercurrent braking of induction motors - how it works

Countercurrent braking of induction motors - how it works

Advantage: Very fast deceleration
Disadvantage: Large current consumption

Iinverse current = V + Vind
.                         Zwinding


DC braking for three-phase induction motors

The stator of the switched off but still rotating motor is connected to a direct voltage. The direct current magnetic field induces voltages and thus causes currents that have a braking effect (=> Lenz's rule, eddy currents).

Braking of electric drives - DC braking for three-phase induction motors

Braking of electric drives - DC braking for three-phase induction motors

Disadvantage: Braking energy generates heat in the rotor


Regenerative braking

If the braking energy is converted into electrical energy, the machine operates as a generator during the breaking process. If the energy is supplied to the mains, this is referred to as regenerative braking.

Asynchronous motors can only work as generators according to this method if the rotor speed ist greater than the speed of the rotating magnetic field speed (RMF) or if torque and RMF have different signs.

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