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Old 16th May 2006, 07:56 PM   #1
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Default Odd toroid and odd issue...help...please!!

I have literally stolen a couple of 1kva potted center Amveco toroids. The problem is as follows:

The label states the windings are <primary- 2*32v> and <secondary-120v>..this is not a typo. I believe these to originally be for some type of solar powered rectifier.

I applied 14v ac using a small trafo I had on hand to one of the primaries and had ~55v ac on the secondary. OK, now I am sure what winding is what. By the way, the 120v winding measured anywhere between .2 to .6R depending on which way the wind blows

Is it possible to run a toriod reversed. Can I run a secondary as a primary and vice versa? When I apply 120v to the 120v secondary I get a small explosion I have played with resistors on that 120v winding and managed to see 32v on the 32v winding but as soon as I do a live bypass to the resistor I get another small explosion

Are toriods different than EI in this respect?
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Old 16th May 2006, 08:41 PM   #2
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Hi mpmarino,
One wonders if these aren't meant to deal with a square wave. Something like a Carver Mag coil. The direction wouldn't matter.

I bet the same thing happens if you feed 32 Vac sinewave into a primary winding.

-Chris
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Old 16th May 2006, 11:27 PM   #3
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Thanks,

The label also indidates 60Hz.....

Could the inrush be so high it is just appearing like a short? ,,, I have yet to try a lightbulb in series.


on the 32v idea:
I've got 32vac kicking round here somewhere..I'll try that too.
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Old 16th May 2006, 11:36 PM   #4
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Hi mpmarino,
Carver Mag coils are 60 Hz. Waveform is everything. It's saturating with a sine wave input.

If you were to use a variac, you may find the current rising to a high level at only 40 ~ 60 Vac. Use one of your amps to feed the transformer with a square wave. That might still draw too much.

Have you ever looked at an inverter waveform for an inverter? It's basically a low duty cycle rectangular wave. Very approximately the rms value of a sine wave.

-Chris
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Old 16th May 2006, 11:45 PM   #5
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Thanks!

Yes, I see your point..makes sense.

I just want you to be wrong
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Old 16th May 2006, 11:49 PM   #6
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I can understand that. I do too, for your sake.

-Chris
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Old 16th May 2006, 11:53 PM   #7
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...but, in the meantime, what the ---- is a Carver Mag coil ????
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Old 17th May 2006, 12:13 AM   #8
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Hi,
It's a little metal thing that looks exactly like a power transformer, but with vastly different characteristics. It saturates easly when presented with a sine wave. Many techs like to short out the triac "switch" to test them on the bench. That way they can force the amp on. Well of course, it draws a ton of current and blows the fuse if they are lucky. Sometimes the caps and things explode since the voltage rails just went wayyyy high.

The mag coil wants to see a variable phase chopped AC waveform just like a triac dimmer. Except it's also really picky about the net DC being zero. Otherwise we are back to high current draw. The operating principle is current. Current in, current out. It's smaller than an equivalent transformer.

-Chris
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Old 17th May 2006, 12:44 AM   #9
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Ah I see. Sooo I'll just stick an electric heat triac T-stat or a high powered dimmer in front of it and I'll be all set.

Just kidding.... but who knows!
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Old 17th May 2006, 04:47 AM   #10
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Your right on the money Chris. The 32v taps do the same thing. They are useless lumps.

Hey, at least the copper is worth something! Maybe I can do something with the cores.....Blahhhh!

Thanks for your help!
Marc
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