I pulled a very old 150VA unit out of a dumpster. With a little testing it became clear the cap on the "resonant" winding was shot, internally shorted. No markings on the cap except a penciled "44". Guess from the size and age 1-3uf.
I put together a string of 220VAC 10uf caps, since at least 600VAC sits on the resonant winding the largest value I can test is 3.3uF. Then 2.5uF, etc.
With 2.5uF it seems to works like it should. In fact driving a 40W bulb (a pretty light load) it will hold 100V - 120V from 30V (!!!) to 130V in. Pretty amazing.
But... I'd like to find the actual spec'ed value for the cap. I've not been able to find anything on the web so far. Any guidance would be helpful. Maybe a procedure for determining the right value by testing?
Thanks...
I put together a string of 220VAC 10uf caps, since at least 600VAC sits on the resonant winding the largest value I can test is 3.3uF. Then 2.5uF, etc.
With 2.5uF it seems to works like it should. In fact driving a 40W bulb (a pretty light load) it will hold 100V - 120V from 30V (!!!) to 130V in. Pretty amazing.
But... I'd like to find the actual spec'ed value for the cap. I've not been able to find anything on the web so far. Any guidance would be helpful. Maybe a procedure for determining the right value by testing?
Thanks...
"Field Replacement of Capacitors
"Capacitors used in all CVS transformers are of the highest commercial
grade available. Nevertheless, there is a certain small percentage of failure.
Sola/Hevi-Duty’s guarantee includes free replacement at the factory of any
capacitor unit that fails within one year from date of purchase. Older units can
be replaced at moderate charge.
"It may be possible to test and identify defective capacitors in the field, and to
make field replacement with new units shipped from the factory. In all such
cases, factory advice and cooperation should be requested in advance."
http://www.clrwtr.com/PDF/Sola-Hevi-Duty/Sola-CVS-Hardwired-Series.pdf
Call them, they still in business.
Contact Us | Appleton Group | Appleton, EasyHeat, Nelson, Nutsteel, O-Z Gedney, SolaHD
"Capacitors used in all CVS transformers are of the highest commercial
grade available. Nevertheless, there is a certain small percentage of failure.
Sola/Hevi-Duty’s guarantee includes free replacement at the factory of any
capacitor unit that fails within one year from date of purchase. Older units can
be replaced at moderate charge.
"It may be possible to test and identify defective capacitors in the field, and to
make field replacement with new units shipped from the factory. In all such
cases, factory advice and cooperation should be requested in advance."
http://www.clrwtr.com/PDF/Sola-Hevi-Duty/Sola-CVS-Hardwired-Series.pdf
Call them, they still in business.
Contact Us | Appleton Group | Appleton, EasyHeat, Nelson, Nutsteel, O-Z Gedney, SolaHD
Not wanting to spend too much money I dinked around and found that a 3.9uF cap seemed about right. Also that a Sola is probably not the thing for audio use. Basically it regulates the RMS voltage (measures properly on a scope) by clipping the sine wave on the output. The regulation is incredibly tight for such a simple seeming device, but way too scraggy for me to want it near anything I'd listen too.
You might be surprised, depending on the equipment. A "squashed" AC line waveform
could ease stress in the power supply, and might well result in less supply noise.
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Back in the days of B/W TV receivers with unregulated circuits, whose brightness and image size would depend on AC mains voltage, and whose raster synchronization would start to miss at just -20% low line, these resonance/saturation stabilizers were top notch. I remember being 10 years old and spending weekends in a rural area, B/W TV only, and my grandfather, an electrician, got a faulty unit like that as a gift, about 300W, he would not know how to repair it, and I was too young to understand either, but finally like 25 years later I understood how it worked.
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Funny... I was talking to my brother, who sells industrial equipment, and he said that a 3-phase Sola driving a 3 phase full-wave rectifier is widely regarded as the one of the stablest, reliable and robust DC sources around.
Looks like some real testing is in order.
Three phase power is much better than two phase, with only a small drop between the sine peaks,
so the capacitors discharge less, and charge more often, than two phase. With the voltage regulation
transformer, that's about as good as an AC line gets.
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The basic Sola is rounded square waves, as you note.
There is a "harmonic corrected"(?) version which is more sine-like, and what you generally want for powering stock electronics.
> only a small drop between the sine peaks
And they are not really Sine in the un-corrected model. They output very smooth DC, even before you go to 3-phase. I had some monster mini-computer DC PSes which worked that way (single phase). This line of Solas was specifically marketed and specced for DC rectifier work.
For most folks, an arbitrary Sola plucked from trash is probably not right for any purpose they have except maybe filler in a concrete foundation. (I'm jacking and re-founding an old house, so the thought comes to my mind.)
There is a "harmonic corrected"(?) version which is more sine-like, and what you generally want for powering stock electronics.
> only a small drop between the sine peaks
And they are not really Sine in the un-corrected model. They output very smooth DC, even before you go to 3-phase. I had some monster mini-computer DC PSes which worked that way (single phase). This line of Solas was specifically marketed and specced for DC rectifier work.
For most folks, an arbitrary Sola plucked from trash is probably not right for any purpose they have except maybe filler in a concrete foundation. (I'm jacking and re-founding an old house, so the thought comes to my mind.)
Roughly on topic, while giving my house a much-overdue cleaning I discovered something covered in dust that I forgot I even had. It was a Tripp-Lite LS600b line stabilizer/conditioner, 600W, 2 receptacles. I decided to try it before pitching it into my dumpster. What a difference. I ended up hooking my unfiltered industrial power strip to it so everything would be on it, notably my #2 desktop that does crossovers and my power amps. I avoided my surge protected strip. It caused more noise; I read that such things often worsen neutral-ground voltage discrepancy. I didn't open the TL box to check the innards; the results sold me.
The obsolete conditioner does a great job. It's been superseded by a new model (LC600?) which I hope works as well. It's not an 'isolation transformer', though it certainly has a line transformer (put your hand on it). Ground is feed-through to my knowledge, which is fine with me, and it'll handle down to 87V brownout. It cleaned my output right up despite the fact that my line voltage doesn't look that bad, nor is it prone to fluctuation.
The obsolete conditioner does a great job. It's been superseded by a new model (LC600?) which I hope works as well. It's not an 'isolation transformer', though it certainly has a line transformer (put your hand on it). Ground is feed-through to my knowledge, which is fine with me, and it'll handle down to 87V brownout. It cleaned my output right up despite the fact that my line voltage doesn't look that bad, nor is it prone to fluctuation.
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