Brake, Braking mode

Consider a case where a load is placed on a lifter, which is raised by a motor, as shown in figure (a). If the motor decelerates to a certain load, the counter electromotive force decreases and the current increases, creating a new state of equilibrium，up to a certain load. If the load is further increased or the applied voltage is lowered, the motor cannot withstand the load and starts to reverse as shown in figure (b). This state is known as brake mode. Since a substantial amount of copper loss is generated in the winding, it is undesirable to run a motor in brake mode for a long time. In figure (c), → shows the state where the applied voltage has dropped without changing the load.