Amps

[mreagant]

I have a few HO locomotives with Digitrax decoders designed for N or Z.  I've read that they should have a max amperage  draw of 1/2 amp.  I've had no issues at all, but I'm wondering under what circumstances might there be amperage that could put them at risk of failing.  Is it simply how many cars the loco is hauling and causing the the motor to work hard.  Does it have anything to do with how many other engines are running at the same time?

I like these smaller decoders for several reasons, but don't want to cook them.  System is MRC PA Wireless with no booster power supply.

[rrinker]

 Even the Digitrax Z decoders are good for 1 amp continuous, 2 amp stall, so they should be fine for HO locos. What make locos are they? Generally, only older Athearn units and some early Proto 2000 models exceed 1 amp even when you grab the motor and keep it from turning (stall). MUCH older equipment can also easily draw more, but going on models made in the past 20 years, that's about it.

                              -- Randy

 

[Texas Zepher]

mreagant

Is it simply how many cars the loco is hauling and causing the the motor to work hard.

Generally Yes.  However, a well configured locomotive will spin its wheels before it hits the current draw necessary to fry the decoder (or motor for that matter).  That way if it will pull the cars the decoder should be safe.

Does it have anything to do with how many other engines are running at the same time?

No, that is where the amps rating of the original command unit or booster comes into play.

[jeffrey-wimberly]

 Those small decoders are pretty tough. I have two HO SDP40F's (one on an Athearn BB chassis and the other on a P2K E6 chassis) that can pull a 25 unit train without turning a hair. Both have Digitrax DZ125 decoders.