The fan timer relay was specially designed to control two-stage motors. The on- and off delays are separate and continuously adjustable. It is controlled using a two-stage switch. The motor contactors are controlled using the two mutually locked outputs. How it works: 1. If level 2 is selected directly, level 1 is switched on first for the set start-up time so that the fan can run up to the nominal speed. Level 2 is then activated. 2. When switching from level 2 back to level 1 or to the OFF position, a switch-off delay is triggered so that the fan can first coast to a stop before level 1 is activated. 3. If level 1 has already been switched on for at least the set start-up time, switching to level 2 takes place immediately. When switching from level 1 to 2, the interruption may be a maximum of 250 ms. If this time is exceeded, the process is as described in point 1.