Fast response circuit with contact control

After the DC electromagnet (such as electromagnetic decoupler, solenoid valve, etc.) is powered on, due to the self-inductance of the coil, the current
rise rate is limited, causing the electromagnet to attract slowly. In order to improve the attraction speed of the electromagnet, in addition to the strong excitation method,
some improvements can be made to the peripheral circuit without changing the structure of the DC electromagnet to achieve the actual requirement of fast response on and off
.
    The circuit is shown in Figure 6-14. It uses a freewheeling diode VD on the valve electromagnet coil. This plays
a role in quickly extinguishing the arc. This circuit is only suitable for occasions where the on-off time requirement is not high. If the on-off time is on the millisecond level, the electromechanical inertia of the contact
control itself cannot be increased, and arcing occurs between the contacts , so that the solenoid valve cannot be guaranteed to be on and off reliably.