Usually an NO valve differs from an NC valve due to the different principle of the electromagnetic actuator and its direction of movement. The figure below shows, from left to right, a cross-sectional view of an NC valve, an ordinary NO valve and a variant NO valve based on the magnetic system of an NC valve.

In case of the NC valve in the first picture, the moving core is pulled to the fixed pole by the electromagnetic force and the seat seal releases the valve seat (nozzle).

In case of an ordinary NO valve as seen in the second picture, the direction of the moving core is changed. The core is pushed down towards the fixed pole. At the same time, the seal carrier is pressed onto the nozzle via a connecting element and the valve is thus closed.

Another variant of an NO valve is shown in the picture on the right. The magnet system of an NC valve is used here, but the position of the nozzle is mirrored on the horizontal axis. The upward movement of the core releases the seal carrier, which closes the nozzle via a spring. This principle enables the use of an NC magnet system to implement an NO function.