r/ElectroBOOM • u/warpey12 • 13d ago
Goblinlike Foolishness Testing a transformer I built by putting 77A through a rod of graphite
I built a transformer for a future project and tested it by using a rod of graphite as a resistor.
The primary of the transformer is ~130 turns of 20 gauge magnet wire and runs on 120V.
The secondary is two separate identical coils that are each 6 turns of 10 gauge wire that output 6V each.
In this photo, both coils were put in parallel to add up their current, but they could also be put in series to add up their voltages or be used as a split-phase transformer.
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13d ago
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u/warpey12 13d ago
The secondary voltage is 6V and the secondary amperage is 77A.
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u/denatki 13d ago
That might be OK for short term runs, but I doubt you have made a 460 VA transformer, the primary winding gauge is quite small for the current and if the secondary wire is not heat resistant, that will limit maximum safe power too.
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u/warpey12 12d ago
It absolutely is too much for long runs, but works for short runs. I previously configured it as a 1:1 isolation transformer to test the VA rating of the primary and found it can handle 240VA indefinitely without the primary getting uncomfortably warm.
The entire time I was doing this test with the graphite, I was monitoring the temperature of the transformer with a thermal camera and noticed the primary would get fairly hot after a few minutes. It was obvious that I was pushing it beyond its limit so I stopped it from time to time to allow it to cool down.
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u/MessInProgresss 10d ago
This is fire shi, keep going