DC Powerpacks for N Scale vs HO

Model Railroader General Discussion (Model Railroader)
1

Many years ago when N Scale came out, there was a need for an N Scale only power pack. One could not use HO packs unless modified with a resister. Is this still true? I ask because I am planning to add one of the BCH Minitrains and a coal mining line to the layout, and wondered if I needed a specific sized powerpack. I am still a dinosaur and rely on DC.

Thanks

Chuck

2

It depends. A few cheap power packs still use rheostats (variable resistance) to control the output voltage. In this case the voltage to the track depends upon the current passing through the rheostat. The higher the current, the more voltage dropped in the rheostat, and the less voltage available to the track (at the same rhoestat setting). Because N locomotives typically drew half the current of their HO counterparts before can motors became universal, an HO rheostat-based power pack would have difficulty controlling the lower speeds of an N locomotive. That’s why the resistor was added.

The same situation has occurred in HO with the advent of low current can motors. If you have a mix of open frame and can motors, a rheostat just isn’t going to cover very well.

Today’s MRC power packs, and all but the low end trainset powerpacks have switched from rheostats to transistors or integrated circuits for direct control of voltage to the track. Within reason, different current draws will not impact the track voltage at a given power pack throttle setting. All MRC Tech series power packs from Tech 2 on feature direct voltage control.

One way to check is to measure track voltage with no load on the track. If the voltage varies smoothly with the throttle setting, you have direct voltage control. A rheostat with no load will have a high minimum voltage and little variability with throttle movement.

Because N scale locomotives tend to run unrealistically fast at 12 volts, having a maximum voltage setting on the power pack can be a desireable feature.

my thoughts, you choices

Fred W

3

No…Any quality power pack will work…I prefer my Tech II.

Any MRC power pack will fill your needs.

http://www.modelrectifier.com/index.asp

4

Fred,

Thanks for the info. Yes I had some old powerpacks but over the years have gone to MRC Power Command 9500 for my layout. I have two walk around throttles connected to the DC and use the tried and true two cab block DC system.

So if I add a separate transister style throttle for the narrow gauge BCH minitrain I should be OK.

Thanks

Chuck