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?
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?
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
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
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
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
Hi Marc,
You know, you may still get somewhere with these. Rectify and filter the incoming AC, copy a Carver PM1.5 power control section.
Give the triac dimmer a try with no load. Measure the output voltage. You may find you have full voltage at 70%. In that case you may have a really cool supply figured out.
Using a Carver variable phase control is wise as they already got the bugs worked out.
-Chris
You know, you may still get somewhere with these. Rectify and filter the incoming AC, copy a Carver PM1.5 power control section.
Give the triac dimmer a try with no load. Measure the output voltage. You may find you have full voltage at 70%. In that case you may have a really cool supply figured out.
Using a Carver variable phase control is wise as they already got the bugs worked out.
-Chris
Hi,
I don't know anything about your specialised transformers.
But back to one of your earlier questions.
You can run a mains transformer back to front.
It appears to work just as well as a step up rather than it's designed function of step down.
There may be a slight performance benefit when used the normal way.
A major disadvantage of wrong way round is that the high voltage winding is exposed to the outside and could be damaged by careless handling and if it did develop a fault could lead to electric shock risk.
The protection provided to the mains side by the heavy secondary winding can not be just co-incidence.
I don't know anything about your specialised transformers.
But back to one of your earlier questions.
You can run a mains transformer back to front.
It appears to work just as well as a step up rather than it's designed function of step down.
There may be a slight performance benefit when used the normal way.
A major disadvantage of wrong way round is that the high voltage winding is exposed to the outside and could be damaged by careless handling and if it did develop a fault could lead to electric shock risk.
The protection provided to the mains side by the heavy secondary winding can not be just co-incidence.
Well....
I hooked this thing up to a 1000w Leviton triac dimmer. Ahem, can you say BZZZZZZZZZZZZZZ!? The trafo almost rattled off the table. That won't do
In poking around here and there on the web I found out that large toroids, depending on thier design, can pull HUGE (more than I thought) inrush. Also, They hate DC on the line (I already knew this but I never thought it an issue here).
I retested the dang thing. This time with a dc blocking circuit and a 1r resistor in series with the mains. The power up is un-eventful. I can now do a live bypass of the 1r resistor..no explosions. I then loaded the thing to 2.5KVA (it's rated at 1kva) using a bunch of 250watt power resistors I have. I only lost 3 volts during the test and the temp of the trafo only rose 4C. I think I can use these things
BTW: Thanks guys for keeping me goin' on these. I was pretty close to turning them into scrap
I hooked this thing up to a 1000w Leviton triac dimmer. Ahem, can you say BZZZZZZZZZZZZZZ!? The trafo almost rattled off the table. That won't do
In poking around here and there on the web I found out that large toroids, depending on thier design, can pull HUGE (more than I thought) inrush. Also, They hate DC on the line (I already knew this but I never thought it an issue here).
I retested the dang thing. This time with a dc blocking circuit and a 1r resistor in series with the mains. The power up is un-eventful. I can now do a live bypass of the 1r resistor..no explosions. I then loaded the thing to 2.5KVA (it's rated at 1kva) using a bunch of 250watt power resistors I have. I only lost 3 volts during the test and the temp of the trafo only rose 4C. I think I can use these things
BTW: Thanks guys for keeping me goin' on these. I was pretty close to turning them into scrap
Actually I wasn't clear. I could not make the dimmer work. Looking at the scope, the dimmer's output looked almost exactly like what I've seen in a Carver manual <ahem>, even driving the toroid. The dimmer never broke a sweat, the traffo however . This traffo does NOT like the cut waveform at all, even at a few volts
I'm on mains power now and if I'm careful how I juice it up, It's fine It is a tiny bit 'buzzy' though. Seems every toroid I get my hands on is a bit buzzy
. This traffo does NOT like the cut waveform at all, even at a few volts I'm on mains power now and if I'm careful how I juice it up, It's fine
It is a tiny bit 'buzzy' though. Seems every toroid I get my hands on is a bit buzzy- Status
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