Karls,
This does help. I believe you are right and your explanation is plenty clear, thanks.
Ted |
To try to clear up the confusion here:
Normal house service is wired 240v balanced, meaning two 120v legs in opposite phase plus a neutral wire. The two 120v legs alternate in the panel from one breaker slot to the next in a vertical direction, on both sides of the panel. Any double circuit breaker (just like your clothes dryer uses) will give you 240v balanced. On the other hand, all 120v is taken from one or the other 120v legs plus the neutral wire. Half of your house is wired from one 120v leg, and half from the other, in a random fashion determined by the guy who wired up the panel. There is no way on heaven or earth to get balanced 120v (meaning +/- 60v with neutral) out of this setup by simple wiring changes. You must use a transformer. I hope this helps. |
Thank you all for your answers. My request was for a Do-it-yourself type of project, without involving expensive transformers. (I am positive that I have read this approach in a past issue of Stereophile if memory serves me right.)
The changing of the electrical panel sounds more like a project that I would be inclined to install first.
Ted |
Karls, yes, that is true. However, in keeping with the original poster's question, I was addressing the house wiring/service panel only.
Also, since I've been wanting to do this only for my amp, thus leaving it at 230 volts and converting the amp to 230v, I had no need myself to research down-converters for 115v. So in my illustrations above, I stayed away from what I did not know.
And in my posting above where I describe how one can obtain balanced power at the service panel, at least one poster here responded by stating what I described could not be done. Unless of course, one were to use that line for an oven or clothes dryer.
At least some of us know that statement is simply untrue.
-IMO |
Stehno, there are two ways to get there: One, take your house's 240v supply and run it through a stepdown transformer wound 2:1 (240v to 120v). Or two, just pass one of the 120's through an isolation transformer (wound 1:1 with a center tap for ground). The end result is the same. One approach may be quieter than the other depending on the type and magnitude of noise on your AC lines, but it would be hard to say which would be better without trying both. |
For those that like to read, I've attached a url from Equi=Tech's website along with one paragraph:
http://www.equitech.com/articles/bpng.html.
Tphalieros, perhaps this is what your original inquiry was about. The defining paragraph states:
"Balanced AC is simply 120 Volts that has been split evenly across two AC mains. One phase is +60V while the other is -60V. The mains are always 180 degrees out of phase across the load and therefore sum to 120 Volts, the same voltage and frequency for which equipment power supplies were designed. In this case however, the reference potential (ground) has been located at the midpoint between the two mains so there is no "neutral" wire."
Hope this helps.
-IMO |
karls -
Good point, the important thing is that you can't rewire a breaker to get balanced power.
-Ed |
Karls, what would be the purpose of an isolation transformer? Could you be thinking of a down converter?
A down converter would be required if somebody has set up a 230 volt circuit/line (balanced power) at the service panel with the intension of using that ciruit with 115 volt components.
-IMO |
I believe that Exactpower makes a unit that does this, for around $1k. You can't get there just by simple wiring changes to your existing house wiring; as stated above, you need an isolation transformer and they are not cheap. |
Ed, any time you have a circuit where the opposing phases cancel each other is also known as balanced power. Whether it be +60 and -60 or +120 and -120.
To the best of my knowledge anyway.
I've read many of the papers found on Equi=Tech's website some time ago. I believe those papers will substantiate my statements.
And Ed, please substitute amplifier for clothes dryer. It helps add credibility to my statements in my previous posting.
-IMO |
what Stenho is talking about is wiring up 220v power, like you would for an oven or clothes dryer.
the sort of balanced power that applies to audio, uses a large toroid (usually) isolation transformer to convert from 120+/0- to 60+/60-. I have a unit right now from Equitech (the 1.5Q, equitech.com) that does this, it's a monster (80lbs or so), but does 15A of power so the whole system can run on it. If you need less power, Monster cable makes a product that does 5amps or so (HTPS 7000, I have one for sale, coincidentally). Equitech also does breaker-panel style units that can run the whole house balanced. Their expertise is in this arena, they do a lot of BP stuff for recording studios, etc. It definitely is an upgrade to the system, I think - if you can, try one out in your system, the differences/improvements are noticable.
-Ed |
Hopefully somebody will come along to clean up my post and verbiage here.
From what I think I know, in order to obtain say a 20 amp 240volt (balanced power) circuit, you would need a 20 amp dual-circuit breaker installed at the service panel.
Of course, this is assuming you have one slot available on both phases/legs of the service panel. One directly across from the other.
Secondly, you would need 10/2 gauage wiring. The black or hot lead is connected to one side of the dual circuit breaker and the white or neutral is connected to the other side of the dual circuit breaker.
There's a number of safety issues involved but I believe that's it in a nutshell. Grounding is optional but recommended.
And of course you must ensure your equipment is wired for 240 volts. If you are looking for 120 volt balanced power, then I believe there's some kind of down converter required to bring the 120 + 120 volts down to 60 + 60 volts.
-IMO |
There are power devices that will give you clean balanced power. Blue Circle, Exact Power, and some others. |
