3-18 B90 Low Impedance Bus Differential System GE Multilin3.2 WIRING 3 HARDWARE3CONTACT INPUTS:A dry contact has one side connected to terminal B3b. This is the positive 48 V DC voltage rail supplied by the power sup-ply module. The other side of the dry contact is connected to the required contact input terminal. Each contact input grouphas its own common (negative) terminal which must be connected to the DC negative terminal (B3a) of the power supplymodule. When a dry contact closes, a current of 1 to 3 mA will flow through the associated circuit.A wet contact has one side connected to the positive terminal of an external DC power supply. The other side of this contactis connected to the required contact input terminal. If a wet contact is used, then the negative side of the external sourcemust be connected to the relay common (negative) terminal of each contact group. The maximum external source voltagefor this arrangement is 300 V DC.The voltage threshold at which each group of four contact inputs will detect a closed contact input is programmable as17 V DC for 24 V sources, 33 V DC for 48 V sources, 84 V DC for 110 to 125 V sources, and 166 V DC for 250 V sources.Figure 3–16: DRY AND WET CONTACT INPUT CONNECTIONSWherever a tilde “~” symbol appears, substitute with the slot position of the module.There is no provision in the relay to detect a DC ground fault on 48 V DC control power external output. We recommendusing an external DC supply.827741A5.CDR24 to 250 V(Wet)(Dry)Contact input 1Contact input 2Contact input 3SurgeContact input 4~7aCommon~7b~7c~8a~8b~8cContact input 1Contact input 2Contact input 3SurgeContact input 4~7aCommon~7b~7c~8a~8b~8cControl powerSurgeB5bFilterB8bB6bB6aB8aCritical failureB1b48 V DC outputB3bB1aB2bB3aHI+LO+Power supply moduleTerminals from type 6Bcontact input/output moduleTerminals from type 6Bcontact input/output moduleNOTE
