I was wondering can you let the locomotive sit at an idle for an extended period of time when using DC? I have 2 BLI C30-7 units and I love to listen to the idle but I dont want to burn the motor up.
I’ll break my own rule and reply to your post even though I don’t have a sound unit on DC.
My understanding is that decoders on DC do not switch the motor on until the track voltage reaches beyond the voltage needed to drive the sound part of the decoder. So I would think it is completely safe to do. To be sure, you could put a voltmeter across the motor while you have track voltage at a level that makes the sound work. If you see less than 1volt or so, it will be OK, any more than that and I wouldn’t leave it on for long periods of time.\
Cheers
The idling sounds made by a decoder when sitting still is only milliamps, but the sound is going to go on and off as you increase or decrease the DC throttle. I don’t understand how you are keeping the locomotive from taking off when you increase the throttle to run a different engine, though, because it does take a few volts on the track to keep the sound alive.
But, to answer your question, no, it is not going to harm the decoder – the motor, possibly, because it is receiving voltage but not enough to make it turn over, and that will generate heat in the motor’s windings.
To be on the safe side, don’t do it with a DC throttle. If you had DCC, it could cause no harm at all.
Take the shell off and feel the motor and decoder after letting the engine idle for 5,10,20 minutes.
If they are not hot, then you are fine.