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Originally Posted by smithb98
So then I notice a tiny little wisp of smoke coming from the big resistor .... It started to turn dark grey and was incredibly hot
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Good heating elements!
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Put in the .47ohm resistor and it worked great though it only went down to 3 or 4 amps and then defaulted to .40
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So it looks like your power supply needs
at least 1/2 ohm or more to operate.
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but I'm not sure why you said I shouldn't see more than 3 volts if I am plating at 6 amps with a 1ohm resistor. Wouldn't my volts be 6?
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You're right, I didn't explain that fully.
You're never likely to see more than 3 volts
at the plating tank (from anode to cathode). Any inline resistor will have it's own voltage drop. The 2 voltages, added together, are what the power supply has to furnish.
eg, if you take 2 resistors of
equal value in series (actual value doesn't matter, as long as they're equal), and connect them to a 12v battery, each resistor will drop 6 volts. It's this voltage that you use in calculating the wattage.
Unequal value resistors will each see a different voltage, depending on the actual resistances, which will sum up to the applied voltage.
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Do they make a 1ohm resistor rated at 100watts? 100 watts=10amps x 10 volts?
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You bet they do, but you won't find it at Radio Shack.
If you're in or near a big city, you might find an electronics supply house where you can get one quick.
Otherwise, shop online. They're not cheap, nothing that big ever is:
You might find cheaper by searching surplus stores.
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though re-reading your post, you pointed out the obvious. If I'm not having problems, say, below 6 or 7 amps, I would only need a 1ohm resistor rated to handle 36 or 49 watts.
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You got it! Figuring this stuff is not cut-n-dried, may take a little experimentation. That's why higher wattage is better, it may be overkill, but you won't have to wonder if it's enough.
Sean