Snubbers and inductance, again
A friend of mine just saw the new NCE snubbers and asked me how many he should buy for his layout. His main power bus is abut 100’ long with an 8 amp booster so it should benefit from having snubbers. This seems to be one of those topics that keeps on coming back so let me just try and boil it down to some simple guidelines.
- Inductance is a property of wires carrying an AC current (DCC is a type of AC) which can lead to various issues with DCC. Symptoms include loss of control, run away trains, reduced track power in areas a long way from the booster, failure of the booster short circuit protection to work all the time, unexplained changes in CV settings, and blown decoders. If you experience any of these symptoms read on, otherwise pat yourself on the back and count yourself lucky.
If your power buses are greater than 30′ long, and/or you are using boosters rated at 5 amps or greater then you might expect to see inductance related issues.
If you built your layout before inductance was identified as a potential problem and you did not twist your wires, and they are longer than 30′, or you use boosters rated at 5 amps or greater, then snubbers may eliminate inductance related issues.
If you build a layout and plan to use buses longer than 30′ and boosters of 5 amps and larger you can prevent inductance related issues by twisting your bus wires 2-3 times per foot, or using zip cord for power buses.
If you are not having any inductance related issues then don’t worry about it.
For more information on this topic search for inductance or snubber in the search box at the top of the website page, read my DCC Corner column in the May 2015 Model Railroader, or read my book “Wiring Your Model Railroad”.