The commutation and reset time of the four-column hydraulic press is normally 5 to 7 seconds after the electromagnet of the four-column hydraulic press is powered on, and the time until the spool is switched off is 5 to 7 seconds, and the time from the power off to the spool returning to the initial position The moment is the moment when the solenoid valve is reset. The hydraulic power of the four-column hydraulic press will increase with the increase of the flow rate, and the thrust of the electromagnet itself is limited, so the large overcurrent capacity of the solenoid valve will be restricted, which is different from that of the spool machine.