A Capacitor Discharge Unit for twin-coil points motors

摘要

This Capacitor Discharge Unit, (CDU), is designed to drive twin-coil, snap-action points motors that are widely used on the majority of model railway layouts. These have the virtue of being cheap and easy to install under points. In action, if one coil (more correctly a solenoid) is energised, the points move across to favour one direction for the on-coming loco. If the other coil is energised, the points move across in the other direction. Many rail enthusiasts energise these point motors by simply connecting the two coils to a 15V (or thereabouts) DC or AC supply via momentary contact pushbuttons. Briefly pushing one or other of the buttons operates the points - simple.