FAQ

|3/4/5 Port Solenoid Valves

After changing an ISO standard VS7-6-FG-S-1* to a VQ7-6-FG-S-1*, the valve no longer turns OFF. The solenoid valve is driven by TRIAC output. What are the possible causes of this?

The apparent power of the ISO standard VQ7-6/VQ7-8 series valve has been reduced compared with that of the VS7-6/VS7-8 and VP7-6/7-8 series.
Therefore, the allowable leakage voltage of the AC type is now 12.5% or less of the rated voltage (compared with 20% or less of the rated voltage for the VS7/VP7).
If a leakage voltage exceeding 12.5% of the rated voltage remains in the circuit when the valve is turned OFF, the pilot valve may not recover.
When using an output unit with a large leakage current (TRIAC output such as a PLC or SSR), if the leakage current exceeds the allowable value, connect a bleeder resistor in parallel with the valve.
Contact SMC regarding the special order VQ7 series valve with an allowable leakage voltage that is the same as that of VS7/VP7 series valves.