| Archive for The Unofficial Mamod and Other Steam Forum The Original Unofficial Toy Steam Forum Established 2006 The biggest, most popular global steam forum around! Accept NO imitations! We have a growing community of regular posting members who chat about all aspects of toy and model steam. |
| 27ace27 |
common heater resistance valuesOK, I am going to add to my website, a table of the general resistances for electrically heated engines, and I need data. so far I have empires at about 35 ohms. anybody else? jensens, wilescos, robert fultons, and anything else! |
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| IndianaRog |
Sorry Ace, ohms confuse me...they are either an electrical measure of some sort or a chant sung by Tibet's monks. Seriously, I have lots of electrics but don't have a clue what the ohm rating of their heaters are.
Rog |
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| johnreid |
MY Jensens are from 28 to 36 Ohms.
Using a VOM is a good thing use it to check for shorts to ground frequently, I do so at least every other time I run one, never had a short, but one never knows. I did have on that came that way so especially check Ebay finds before trying to plug them in. Approximate values can be calculated by using Ohms Law if you know the Wattage of the heater. |
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| metalhead100 |
 Tibetan chant hahahha
Allow me to plagiarize Wikipedia........ The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. OHM'S LAW. V = I x R. Where: V = Voltage. I = Current. R = Resistance In electrical circuits, Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them. Jim |
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| johnreid |
Lets do the math
115 Volts X 3.5 amps = 402.5 Watts 115 / 3.5 = 32.8 Ohms I am assuming that the length of the nichrome might vary a little from one heater to the next just as the wire might eventually lose some thickness and lose resistance.. |
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| tmuir |
I'm also guessing 400W is an average value.
I'm sure that if you tested all the heaters they would vary from 400W plus or minus a few percent too. Should we really make Rogs head spin and start talking about the difference between conventional current flow and electron current flow?
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| Roly Williams |
You can calculate the resistance using Ohm's law but that will give you the resistance when hot. It will be somewhat lower when cold. If you measure one cold and then calculate it's hot resistance, the ratio between the two should be similar for heaters of a similar construction.
The other thing to remember is that the resistance will be different between 110 and 220v versions. |
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| Roly Williams |
Don't bother; you'd have to explain the difference between AC and DC first 
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| IndianaRog |
My cover is blown....I don't understand electricity worth a damn, but I CAN hack my way to the finish line getting something wired...it just takes me forever!!! Proof I can do it given enough DAYS, wire and labels!!!: 
Rog |
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| Roly Williams |
You certainly can't complain about a lack of labeling in your work. If only everybody did as well! |
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| AzRob |
All that just for one red light? 
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| IndianaRog |
Nah...one red light and 19 other switches, gauges and fuses...and the dang thing works! | ||||||
| 27ace27 |
 very nice though! BTW that reminds me of something I made... be prepared to be taken back... http://www.instructables.com/id/ATARI-2600-Joystick-LEDs-v1/
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| IndianaRog |
Only insulation was about 3/4" of air space between the gauges on the top lid and circuits screwed to the floor of the console. I did (with a forum member suggestion), remove the metal edges on those round tags so there was no potential of a short circuit. With separate 115 V AC, low voltage AC and low voltage DC circuits all in that box...it was about as complicated as I would ever want to tackle. Somewhat to my amazement it works perfectly! Rog |
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| johnreid |
I know that, when it gets real hot in the summer, I turn on the AC |