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Transformer noise including Powervar

First, all transformers make acoustic noise. That is their nature. But the manufacturer should know how to limit or dampen these vibrations to keep them pretty much inaudible.

The transformer in a power conditioner or power amplifier will make audible noise for primarily one reason: improper AC input. All transformers require a constant specified voltage and frequency just like all other electronics. The AC input requirements are specified on the rear of the unit.

If one feeds the unit improper voltage or frequency, the magnetized plates in the core of the transformer do not operate properly and rattle…hence the noise. And this information comes from the chief engineer at Powervar.

Powervar and many other power conditioners do not regenerate the AC sine wave or regulate voltage or frequency. The AC that goes in comes out less AC TRANSIENTS and AC NOISE.

With that being said, there are many AC line sources that can cause transformer noise including DC on the mains. If you are interested in understanding what they are and becoming educated on the subject, I suggested highly that you read the following article and focus on section 3. “Adverse Mains Conditions”. Go to: http://www.plitron.com/PDF/AES.PDF The article is excellent.

So if you are going to use a Powervar, you should feed it proper AC sign wave. The AC can be full of transients and noise but it has to be the correct voltage and frequency. The Powervar will clean the transients and noise but it is not going to change the sine wave. One can only do that with a regenerator and that comes with a price of course.
drdokman1
ngjockey
1,042 posts
 
I've been playing with transformers for the past year or so in several configurations, including TVC's, autoformers, power, isolation and balancing. I've made every mistake imaginable and managed to make them work. What I've learned is that they're as much of an art as a science. They can forgive blunders and be intolerant of the slightest problem. I'm losing my hair, by scratching and pulling, wondering how one configuration works and another doesn't.

The other thing I learned is that you need a very good ground. Pound that galvanized deep into the earth. It's ironic that one of their greatest benefits is their greatest weakness, DC.
palasr
453 posts
 
I built the second link Jea48 mentions in his post, which is essentially the same as the link I posted. I kept it simple and used a piece of perfboard mounted on nylon standoffs. Everything can be configured point to point, and takes up no more than 3" square. There are no exotic/expensive parts here, and whole shebang ought not to cost more than $10 to build (including the mounting hardware). The thing to remember is that you MUST know what you are doing - this is the AC line we're talking about here, and obviously, the DC blocker is NOT UL approved. I will take some pictures of my DIY Armegeddon, which was based around a Powervar medical isolation device. All I wanted was the isolation TX and the chassis which were nicely adaptable for this use. I removed all the Pi filters and other crap between the AC in and out, and then built the Armegeddon circuit inside the Powervar case (and later installed the DC blocker after the Powervar proved too noisy).
shadorne's avatar
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shadorne
7,333 posts
 
DC offset seems to be a big problem for tranformers especially when driven to saturation. If possible, the best is to unplug the offending device that is feeding DC offset back to the mains (AC or DC motor or another power supply like a chopper power supply for a PC).

If manufactuers used more costly transformer designs that were less easily driven to saturation then DC offsets and acoustic noise would be much less of a problem.
mdhoover
690 posts
 
Jea48: Thanks for the links. Now if I just knew how to read the diagrams.....
"The thing to remember is that you MUST know what you are doing - this is the AC line we're talking about here, and obviously, the DC blocker is NOT UL approved."
-Palasr
Palasr: That would disqualify me from this endeavor, at least for now. DANG!
drdokman1 OP
7 posts
 
Ludimagis:

Might be something on a particular circuit only causing the problem.

Perhaps the transformer is not dampened enough or perhaps it has been damaged. Tighten it down?

Thanks for your response.
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