How DC contactors work

When the coil of DC contactor is energized, the coil current generates a magnetic field, so that the static iron core generates electromagnetic attraction to attract the moving iron core, and drives the contact action: the normally closed contact is opened, and the normally open contact is closed, and the two are interlocked. When the coil is de-energized, the electromagnetic attraction disappears and the armature is released by the release spring, which restores the contact: the normally open contact opens and the normally closed contact closes.