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Bench PSU

HellasTechn

Apr 14, 2013
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Hello every one and Happy New Year !

I have in my hands a big transformer ripped from an old HiFi system (SONY STR-W550).

I am thinkin to use this to make a bench power supply. What circuit would you Recommend
that i use ?

I have searched the net for info about this transformer and the only thing i found is a diagram of the windings from the STR-W550 repair manual.

The winding in the red box gives 36V and has fuses rated 6.3 Amps. I thought that 36V at 6A would make a nice bench psu.
 

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Arouse1973

Adam
Dec 18, 2013
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Happy new year to you also. What do you want your power supply to be able to do? Adjustable current and voltage etc.? Output voltage and current value? Voltage drop sense terminal? Voltage and current reading output?
Adam
 

HellasTechn

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Well for sure i would like voltage control and if it does not make the circuit too complicated Current limiter. About voltage drop sense i am not sure, where would that help ?

P.S. i could measure the rest of the windings to see the voltages if that could help.
 

Arouse1973

Adam
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If you have a longish cable supplying a few hundred mA, and you set your PSU to say 12 Volts. You may only have 11.5 actually at the load. Using a sense terminal you can remove this error.
Adam
 

Arouse1973

Adam
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How does the power supply know what voltage you have at the end of a pair of wires under load?
Adam
 

HellasTechn

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I dont know. I am not sure i understand the question.
Some kind of feedback loop?
 

Martaine2005

May 12, 2015
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I dont know. I am not sure i understand the question.
Some kind of feedback loop?
Hey Constantine,
Adam mentioned length of wires.. Think resistance..
At least that is what I thought of..
The longer the wire..........

Martin
 

Bluejets

Oct 5, 2014
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The winding details may be in the drawing but too small to see.
 

HellasTechn

Apr 14, 2013
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In a PSU with high current capabilities i doubt that cable leignth matters, i think he is referring to the voltage drop because of the load.
 

duke37

Jan 9, 2011
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How does the power supply know what voltage you have at the end of a pair of wires under load?
Adam
There are four wires, two for the power and two for the voltage sense. The supply ups the voltage to take account of the voltage drop. The sense wires take very little current and so the voltage drop in them is negligible. Normally, they are connected to the power supply output with resistors so that if they are not used, the voltage is controlled at the output of the supply.
 

Arouse1973

Adam
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In a PSU with high current capabilities i doubt that cable leignth matters, i think he is referring to the voltage drop because of the load.
Yes. Without the sense terminal, the power supply does not know what the voltage is at the load end. I mentioned it because it can be a good feature to have at times.
Adam
 

HellasTechn

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Well Thank you for the offer, yes why not ! That will take some time though.
 

Arouse1973

Adam
Dec 18, 2013
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I'll see what I can come up with. In the meantime for any of the other geniuses on here that wish to contribute then please do. I have been known to over complicate things at times :)
Adam
 

HellasTechn

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We can do this i am sure ! what kind of e.t. are we after all ?
 
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