DC relay or contactor in addition to using strong excitation pull way accelerate, accelerate the release, but also the following circuit to achieve the purpose of accelerating
the release. Circuit shown in Figure 6-28. The relay circuit can improve the return line number. When the control relay KAi (not shown) pulls in, the result of K normally closed contact initially closed. KAz coil is energized, people avoid string coil back road, so when KAi release, KAz will accelerate the release. Additional value can be adjusted to change the wind resistance of the relay returns coefficient, Rf but not too large, about 1 to 2 times the relay coil resistance RL.