I bought a couple of surplus transformers to build an aleph-x with. They're EI frame, rated 12/13V @ 20A.
I received no hookup instructions, so I measured them with a meter.
What appears to be the secondary side is just 2 lugs, 0.2 ohms between them.
On the primaries, 3 wires, black, white, brown. White to black, 1.2 ohms. White to brown, 1.1 ohms. Black to brown, 0.3 ohms.
Both transformers measure they same, and look new. Obviously, these measurements aren't highly accurate, as they are with a 3-1/2 digit DVM.
Do these numbers make sense? Frankly, I'm scared to wire it up with these kind of numbers. Should I put anything in series with the primary (in addition to a fuse)
?
I received no hookup instructions, so I measured them with a meter.
What appears to be the secondary side is just 2 lugs, 0.2 ohms between them.
On the primaries, 3 wires, black, white, brown. White to black, 1.2 ohms. White to brown, 1.1 ohms. Black to brown, 0.3 ohms.
Both transformers measure they same, and look new. Obviously, these measurements aren't highly accurate, as they are with a 3-1/2 digit DVM.
Do these numbers make sense? Frankly, I'm scared to wire it up with these kind of numbers. Should I put anything in series with the primary (in addition to a fuse)
?
I guess it's as good a time as any to learn about impedance.
Let me give you a hint...look up the esr of a big electrolytic cap...you'll see numbers like 0.010 ohm at 120 Hz, that's not stopping you from using the caps for ripple filtering, isn't it? Actually when you get to the bigger caps you'll notice the ESR drops even further.
If it makes you feel safer use a 2 amp fuse in series with the primary when you plug it in.
Let me give you a hint...look up the esr of a big electrolytic cap...you'll see numbers like 0.010 ohm at 120 Hz, that's not stopping you from using the caps for ripple filtering, isn't it? Actually when you get to the bigger caps you'll notice the ESR drops even further.
If it makes you feel safer use a 2 amp fuse in series with the primary when you plug it in.
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