# Average Resistance of G-Scale Locomotive



## Cephas (Jan 15, 2008)

I am trying to use my Aristocraft 10-amp power supply in a non train-related application (trying to build a electric hot wire styrofoam cutter using NiChrome wire). I can't simply run the current through a Ni-Chrome wire, as there won't be enough resistance and I will short my power supply. I therefore need to simulate the resistance of an average G-Scale Locomotive somewhere in my circuit. 

I do not possess an ohm-meter, so i cannot find this answer out myself. Can anyone provide the average resistance caused by a G-Scale Locomotive? 

I am a college student studying Civil Engineering and this is for a design competition I am involved in. 

Thanks,

Peter


----------



## Pete Thornton (Jan 2, 2008)

One way (from the days of 12V indoor layouts) of avoiding a 'short' is to include an auto headlight bulb in the circuit. In this case, I assume you have a 24V supply, so use 2 bulbs in series. The bulbs allow a fairly high current when lit, but will avoid shorting the supply.


----------



## dbodnar (Jan 2, 2008)

Posted By Cephas on 26 Jan 2011 11:30 PM 
I am trying to use my Aristocraft 10-amp power supply in a non train-related application (trying to build a electric hot wire styrofoam cutter using NiChrome wire). I can't simply run the current through a Ni-Chrome wire, as there won't be enough resistance and I will short my power supply. I therefore need to simulate the resistance of an average G-Scale Locomotive somewhere in my circuit. 

I do not possess an ohm-meter, so i cannot find this answer out myself. Can anyone provide the average resistance caused by a G-Scale Locomotive? 

I am a college student studying Civil Engineering and this is for a design competition I am involved in. 

Thanks,

Peter 

The light bulb suggestion is a good one. If you don't have a meter stop by your local Harbor Freight and pick one up for a few bucks - a good investment.

You may also find some useful information in this article:

Foam Buildings 

I started out with a Lionel transformer and now use a Variac that feeds a step down transformer from an old UPS - works like a charm! You want to deliver only a few volts to the NiCrome wire.

Good luck, Peter

dave


----------



## Greg Elmassian (Jan 3, 2008)

Your problem is that the resistance of a locomotive varies under load. 

Also, the resistance of the nicrome wire varies under current too, it increases with more current, so measuring it "cold" will be problematic. 

In this case I have to agree, try it by slowly increasing voltage until you get what you want. 

On the other hand, if your "project" for some reason encompasses you figuring out the resistance needed with formulas, then you can find tables of resistance vs. length, vs. current for nicrome wire and calculate it. More work that way. 

Regards, Greg


----------



## krs (Feb 29, 2008)

Posted By dbodnar on 27 Jan 2011 08:42 AM 

You may also find some useful information in this article:

Foam Buildings 

I started out with a Lionel transformer and now use a Variac that feeds a step down transformer from an old UPS - works like a charm! You want to deliver only a few volts to the NiCrome wire.




That's all AC stuff - 

If this information is correct











--------- why not just use a G-Scale DC power pack directly with the appropriate 30 gauge NiChrome wire and adjust the power pack voltage appropriately?


----------

