The Carlo Gavazzi Type DAC51 timer is a Star-delta control relay with two adjustable time ranges: Star function (0.1 to 600s) and star to delta function (50 to 130ms).

The output relay is normally in the neutral centre position. When the power supply is applied, the relay switches to star position and the star period starts.

At the end of the set time period, the relay returns to the neutral center position and the set delay between star and delta position starts.

At the end of the star to delta delay (adjustable from 50 to 130ms), the relay switches in delta positionand does not release until the power supply is interrupted for at least 200ms

If the power supply is interrupted for more than 200ms before the star time period has expired, the relay does not operate and the time circuit is set to zero. The relay is then ready for a new time period.