Forward and reverse adjustable speed control circuit with integrated braking function

Figure 3 173 is a forward and reverse adjustable speed control circuit  of a wound asynchronous motor with mechanical braking, energy consumption braking, and reverse braking functions .
    In the figure, KI is a locked-rotor relay (actually an over-current relay); KI2 is an over-current relay; KMi is a forward
contactor; KM2 is a reverse contactor; KMa is a power brake contactor; KM4 is a brake Contactor; KMs is the reverse
braking contactor; KM6 and KM7 are accelerating contactors; YB is the braking electromagnet; KAi is the braking relay; KAz
is the reverse braking relay; KA3 is the power braking relay; KTi, KT2 and KT3 are time relays .
    Among them, the reverse braking relay KA3 is activated when the reverse braking starts and the motor slip ratio is sa:0, and
is released when the speed drops close to zero (that is, when s≈l). A DC relay with a high return coefficient must be used.
    The locked-rotor relay KI only operates when the production machinery is blocked and the motor quickly experiences overcurrent.
    The power brake relay KAs (essentially a time relay ) is used to control the action of the power brake contactor KM3 and further
control the energy consumption of the motor.