Zen :bulb: lite :bulb: Power supply

[Rodeodave]

Hi, I know, we all hate double-postings, and this one is one in some way. I´ve posted this question in the power-supply forum before, but:
1) I´m afraid there's not too many people browsing and

2) I´ve seen that some of you had kind of the same problem with some 50-0-50 supply.

I´ve got a transformer that makes an AC secondary of 45-0-45. My aim is to get two times +60V DC, that´s one +V for each channel. So how to do this? How and where should I ground? Is there any possibility to get two times +60V out of it? Please help.

My other question is concerning the inductance L1, rated 4mH up to 6A. I want to wind that myself, with 40 meters of 16Gauge insulated copper wire (inner radius 41mm, height 20,45mm), that makes 2mH; should do fine, right?
Anyone ever did something like that before? Any advice?

Oh, there´s another one: Since I live in Europe, we have 220V with 50Hz, that´s why it´s really hard to get bulbs rated 110V. I think I´ll try a 220V/1000W per channel. U think it´ll work?

Thank you, David

[Netlist]

David,
Does the transformer have split secundaries? If so, it would be easy to get twice 60V or so after rectification.
As for the choke, I'm not that good in calculating but try Google for that. You'll find plenty of nice Java based calculators.
Also, do have a look at Passdiy.com, I recall Nelson did some experiments with different light bulbs. It's somewhere explained in the first Zen article.
1000W? Hmmm...try it and report.

/Hugo

[Rodeodave]

Hi, the transformer has got two center-tapped secondaries, one rated 25-0-25, the other one 45-0-45. I´ll be using "the other one". There are three wires, 90V across the whole thing, 45V from the center-tap to each end. But what happens if I ground the center-tap? Will there be one positive and one negative?

The inductance: With these dimensions it should become a 2mH one. The problem is that I never did any winding-stuff before, so I´m looking for a little advice.

The bulb: The 220V/1000W-thing is not my idea, I read it on the board. Seemingly people have tried almost everything, from halogene-bulbs to 220V-rated bulbs. I think I´ll just give it a try with any big 220V one.

Thanks again, David

[Netlist]

Using the 45-0-45 winding will do but then you have a few possibilities.
Found a good article http://eceweb2.np.edu.sg/pub.nsf/page/naznotes/$FILE/L8.pdf
Looks like there is more to calculate then the voltage.

/Hugo

[Rodeodave]

Thank u, but the link is broke or can´t be found. Or is it my browser or

Dave

[Rodeodave]

hi, I found something that could be the solution:

http://sound.westhost.com/project04.htm , Figure 1

With a few adjustments in fuse and capacitors...
Looks sweet, but in the zen lite we don´t need negative supply voltage. Can I just leave out V- (BR1-4&BR2-4 not connected) and also ditch C2,C4 ? Could this work? Hopefully does...

Dave

[Rodeodave]

oh, and the link finally works. Thank you.

[Netlist]

Perhaps a full wave rectifier could do. If you can live with the disadvantages.

/Hugo

[uli]

Hi Dave,

Do you know the PSU Designer software by Duncan Munro?

PSU Designer

V E R Y nice tool!

Uli



PS: servas, guadn rutsch!

[Ori]

The best you can do with a 45-0-45 is to use a separate half-wave rectifier (one diode from each end) per channel.
the ground is the center tap, and it's shared between the two channels, which is probably what you want.
As for 60V, that's a tough one. Most transfoemrs running close to capacity would have losses in the order of 10-15%, so expect 52-55V output. The supply cap should be sized for the voltage ripple you can live with and no bigger. The bigger the cap- the higher the losses and the supply noise, due to increased current spikes from the AC line. In any case you should inquire about snubber circuit to "clean up" your supply and always incorporate a good line filter "block" with IEC connector. It's cheap insurance against RF noise - for not much money.
Have Fun!