D

DC Direct Current

DC Distribution (DCD) A module in the power solution that distributes DC power to the loads. It also provides protection for the load cables.

DC Distribution - Fused version (DCF) A DC Distribution module that uses fuses for protection.

DC Distribution - Miniature Circuit Breaker (MCB) version (DCM) A DC Distribution module that uses miniature circuit breakers for protection.

Delta Connection A method of connecting a three-phase source or load in series for a closed circuit (3-wire, plus ground).

Digital Input An input which recognizes an open-circuit and short-circuit.

Digital Output A voltage free relay contact.

Direct Current (DC) A type of current which never reverses its direction. Since the current flows in only one direction, the average value of the current cannot be zero unless the current has stopped flowing.

Double-Conversion A UPS design in which the primary power path consists of a rectifier and inverter. Double-conversion isolates the output power from all input anomalies such as low voltage, surges and frequency variations by converting AC to DC to AC. See Online UPS.

Dry Contact Isolated contacts through which the end user supplies an external circuit. Dry contact UPSs provide basic communication capabilities such as monitoring and shutdown.