One of the DC relay acceleration release circuits

In addition to using strong excitation to accelerate closing and releasing, DC relays or contactors can also use the following circuits to achieve
accelerated release.
    The circuit is shown in Figure 6-28. This circuit can improve the return coefficient of the relay
. When the control relay KAI (not shown in the figure) is closed, the normally
closed contact of K& is initially closed. The KAz coil is electrified and closed to avoid crossing the coil circuit
. Therefore, when KAi is released, KAz will accelerate its release.
    The relay return coefficient can be adjusted by changing the additional resistor wind value, but Rf
cannot be too large, which is about 1 to 2 times the relay coil resistance RL.