At 200w, a switching power supply really makes sense. Just try pricing out a 60Hz transformer rated for 200w or greater, not to mention the large capacitors needed. Then compare that to the cost of a quality PC power supply rated for the same. (And don't forget the parts for voltage regulation, either!)
How about a switcher like this?
http://www.mpja.com/prodinfo.asp?number=17429+PS
The voltage you need, plus a higher current rating, for $25 (plus S/H).
Looks like a bargain to me!
Regards,
Paul
http://www.mpja.com/prodinfo.asp?number=17429+PS
The voltage you need, plus a higher current rating, for $25 (plus S/H).
Looks like a bargain to me!
Regards,
Paul
They only ship to international if you purchase for over 100$, so I've found this one on ebay, it's more expensive, but a switching supply rated at these specs cost over 150$ in my country, so I can save a lot.
Swiching supply
In the specs it looks like I can get the voltage up to 26,4 vdc, so that should be great for my needs.
Regards,
Simon H.A.
Swiching supply
In the specs it looks like I can get the voltage up to 26,4 vdc, so that should be great for my needs.
Regards,
Simon H.A.
Bummer about the shipping. I forget how spoiled I am in the US with good access to parts and (sometimes) reasonable shipping.
Often with an SMPS like the one I linked to, there are two ways to increase the voltage to what you need.
1) There is often a pot that can be tweaked to increase the output voltage to what you need. Just be careful not to go too far and run out of supply range. This can lead to the supply shutting down or coming out of regulation. +/- 5 to 10% is a pretty common range and should work for what you need.
2) There is sometimes "sense" leads that give you the ability to remotely detect the supply voltage and keep it regulated at the load. But, you can also trick the sense leads with a voltage divider into thinking the output voltage is sagging at the load forcing the supply to increase the output voltage to what you need.
Good luck on your project,
Paul
Often with an SMPS like the one I linked to, there are two ways to increase the voltage to what you need.
1) There is often a pot that can be tweaked to increase the output voltage to what you need. Just be careful not to go too far and run out of supply range. This can lead to the supply shutting down or coming out of regulation. +/- 5 to 10% is a pretty common range and should work for what you need.
2) There is sometimes "sense" leads that give you the ability to remotely detect the supply voltage and keep it regulated at the load. But, you can also trick the sense leads with a voltage divider into thinking the output voltage is sagging at the load forcing the supply to increase the output voltage to what you need.
Good luck on your project,
Paul
The skin effect will increase the effective impedance at high frequencies and large wire is less efficient at using space. Take apart the transformer out of even a cheap ATX power supply and remember that if they can effectively cut costs by using one large wire for the secondaries, they will.Tosh said:
Hi,Tosh said:
just try winding the required length of thick wire on to a long bobbin to feed through the middle of the toroid.
Now, try to feed that bobbin through and around the toroid core and try to place that thick wire in neat parallel lays without any kinks.
I suspect the machines that wind toroids have a similar problem getting sufficient tension to straighten out the thick wire.
I can wind 1.6mm (6A) wire but 2mm (9A) is almost impossible for my hands.
We are working at 50/60Hz. Skin effect is a non starter at these low frequencies.
In fact the opposite is an advantage.
Thick wire will help attenuate the HF interference that comes in from the mains. If the winders could use very thick wire in the higher VA toroids it would remove one of the disadvantages of a toroid cf. EI types.
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