NCE BD-20 DCC Block detector

NCE Block detector

The BD-20 block detector module is normally used to indicate the presence of a locomotive, Coaches or other rolling stock in a track section by connecting to AIU01 and sensing electrical current drawn by that rolling stock.

Locomotives will naturally trigger the detector because they draw current through their DCC decoder. (Unpowered rolling stock will not trigger the detector unless equipped with some means of drawing current from the rails such as lights or resistor wheel sets.)

Unlike other detection units the BD-20 requires no direct electrical connection to the track. This block detector can be used with any sized DCC power booster of up to 12 Amps capacity. The track feeder wire for one rail of the block is just passed through the hole in the current transformer on the module (see manual) before connecting the feeder to the track. The more times the wire goes through the hole in the current transformer the more sensitive the detector becomes. (See the section on Detector Sensitivity for some limits on this matter.)