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Contact ConfigurationAccording to the different switching functions of the relay contacts, a difference is made between the various contact configurations whose design and description are specified in DIN 41020.  Make contact (NO contact) A contact that is open in the release (rest) state of a monostable relay and closes (makes) when the relay coil is energized (operating state). Break contact (NC contact) A contact that is closed in the release (rest) state of a monostable relay and opens (breaks) when the relay coil is energized (operating state). Changeover contact Compound contact consisting of a make contact and a break contact with a common terminal. On changing the switch position, the contact previously closed opens first followed by the closing of the contact that was previously open. Twin make contact(Double make contact) Two make contacts configuration, with two electrically connected moveable contacts which are operated simultaneously. Twin break contact (Double break contact) Two break contacts configuration, with two electrically connected moveable contacts which are operated simultaneously. Bridging make contact Compound contact with two simultaneously operating make contacts connected in series. Double pole (single throw version) A double pole relay switches two, electrically not connected common lines with two electrically independent load lines (like two separate make relays). Double throw (single pole version) A double throw (single pole) relay switches one common line between two stationary contacts, for example between a NO contact and a NC contact (like changeover relay or form C). Pre-make contact Twin contact electrically connected where one contact always closes first (pre-make) and opens last. The pre-make contact, for example out of tungsten (high resistive and very resistant to contact erosion), switches the current, while the second, like a low resistive silver contact, carries the load. Single contact Contact configuration with a single stationary / moveable contact pair on the make and /or the break side (compare twin or double contacts). Single pole (single throw version) A single pole (single throw) rel ay connects one common line (moveable contact) to one load line (stationary contact). Single throw (single pole version) A single throw (single pole) relay connects one common line ( moveable contact) to one load line (stationary contact). |