Normally closed motorized ball valves also named Spring return/Capacitor return/Auto-return motorized ball valves,more details please visit http://www.flow-controls.com/news/What-is-fail-safe-or-normally-closed-open-motorized-ball-valve--16.html, 

For more videos please visit our website http://www.flow-controls.com/news/TOFINE-motorized-ball-valve-Videos-42.html

Normally closed:Power to open,no power to close by the way of built-in capacitor.
Normally open motorized ball valve valves also available,it can normally open when power off,meanwhile,if you need fail safe with signal feedback,please refer to 5 wires.

TOFINE: Web: www.flow-controls.com,  Email: sales@flow-controls.com