Hi Guys
I bought a 28 0 28 / 4 amp CT transformer to use it to build my first Gainclone
I suspect the seller has given me a lower than 4 amp trafo , so I wanted to test the amperage myself , the only way I found is to connect the trafo's secondary to an ATX ps 12v , I did this after I measured the seconary resistance which was 3 0 3 ohm, so 12/3=4 amp ,anyway I got only 2.5 dc amp running throug the secondary , the transformer gradually heats up and took about 25 min to be so hot that I can barely touch it , so can this trafo handle say, 3~4 amp ac current.
Thanks in Advance
I bought a 28 0 28 / 4 amp CT transformer to use it to build my first Gainclone
I suspect the seller has given me a lower than 4 amp trafo , so I wanted to test the amperage myself , the only way I found is to connect the trafo's secondary to an ATX ps 12v , I did this after I measured the seconary resistance which was 3 0 3 ohm, so 12/3=4 amp ,anyway I got only 2.5 dc amp running throug the secondary , the transformer gradually heats up and took about 25 min to be so hot that I can barely touch it , so can this trafo handle say, 3~4 amp ac current.
Thanks in Advance
There really isn't any non-destructive way to test the amperage. What you did sounds like quite a torture test; overheating the trafo isn't good for it's health.
I would probably just try it in the gainclone and see how hot it get's playing music. Unless you're playing continuously at high levels, it should (hopefully) be OK.
The voltage sounds a bit high for a gainclone, though. After rectification you'll have close to +-40V. The 3ohm resistances could be a blessing in disguise as they'll drop some voltage when the amp's drawing current.
I would probably just try it in the gainclone and see how hot it get's playing music. Unless you're playing continuously at high levels, it should (hopefully) be OK.
The voltage sounds a bit high for a gainclone, though. After rectification you'll have close to +-40V. The 3ohm resistances could be a blessing in disguise as they'll drop some voltage when the amp's drawing current.
What weight is the transformer?
What type is it, EI, Toroid, Rcore, Ccore?
What diameter wire is used to wind the secondary?
Can you see the diameter of the primary winding?
What temperature was the insulation in the interior of the transformer when the surface proved to be too hot to touch?
Have you blown up your transformer?
What type is it, EI, Toroid, Rcore, Ccore?
What diameter wire is used to wind the secondary?
Can you see the diameter of the primary winding?
What temperature was the insulation in the interior of the transformer when the surface proved to be too hot to touch?
Have you blown up your transformer?
Of course it will.
If a transformer is rated at 4A then you can load it to 4A and make sure that it is running and not getting too hot. You can also expect the voltage to be within approximately 90% of its no load voltage.
If you need more precise regulation figures you are going to need its datasheet.
If a transformer is rated at 4A then you can load it to 4A and make sure that it is running and not getting too hot. You can also expect the voltage to be within approximately 90% of its no load voltage.
If you need more precise regulation figures you are going to need its datasheet.
Still no.
I accept and recommend that a LOAD TEST is the best way to determine the VA rating of the unknown transformer.
But you must have the equipment and knowledge to allow the test to be carried out in a meaningful way. Otherwise the results will be worthless.
Worse, one incompetent Member is quite likely to damage a perfectly good transformer due to lack of resources.
I accept and recommend that a LOAD TEST is the best way to determine the VA rating of the unknown transformer.
But you must have the equipment and knowledge to allow the test to be carried out in a meaningful way. Otherwise the results will be worthless.
Worse, one incompetent Member is quite likely to damage a perfectly good transformer due to lack of resources.
So finally BLACK is BLACK and you do agree.
Hopefully the guy will have some common sense and apply the load gradually.
Maybe 0.5A at a time until the voltage starts to drop.
you did the wrong thing putting on dc in your taffo windings, your finding 3ohm per side dc resistance on your traffo secondary is enough and paints a good picture of already.....
drawing 1 ampere out from your secondaries drops 3 volts per side, so that your 28-0-28 traffo becomes a 25-0-25 traffo.....
drawing 2 amps, your traffo secondary drops some more so that it now becomes a 22-0-22 traffo....
more current drawn means lower voltages.....this is called regulation...
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