Bob Nelson
QUOTE: Originally posted by lionelsoni We're on the same track, Daan, so to speak. I have a similar scheme in all of my locomotives that have electromagnetic couplers. I have a circuit that charges a capacitor from the motor voltage. But whenever there is a little voltage on the motor field coil, a transistor discharges the capacitor into a relay coil, operating it for a second or two. In normal running, the capacitor stays discharged because the field coil is in use. However, in neutral, the capacitor will charge after a few seconds with the voltage turned up, since the e-unit has disconnected the motor voltage from the motor. Then, the next time the locomotive starts, the capacitor charge is dumped into the relay and the couplers open as the locomotive pulls away. I mostly use 9-volt DC relays from Radio Shack; but I have recycled some whistle relays into my circuit to operate couplers.
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