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Plating power supply design (0-15V/30A)

2004

Dear sirs,

I need to develop and manufacture power supply for plating that has to be 0-15V/30A, and it has to have voltage/current regulation. I was thinking that it can be done using phase controlled switch (using triac) on primary side of transformer. This way I can control effective voltage that goes on to plating tank, but I don't have a clue how to establish current regulation?! So if you have any idea or schematic please share it with me so I can continue.

Thank you in advance.

Sime M.
student - Strumica, MK, Macedonia

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You need a current sensor on the secondary side. This is usually a low value resistor (1/10 Ohm or less). The voltage drop across this resistor, which is proportional to the load current, is used as the current feedback signal. The control electronics then treats this signal just as it would treat a voltage feedback signal, cutting back the triac firing angle to limit the current. Often an opto-isolator (also called an optical coupler) is used to isolate the control electronics from the secondary side current sensing. Since the input side of an opto-coupler is an LED, you won't get a signal through until you reach its threshold voltage of around 1 to 2 Volts. This means you will have to supply some bias current to the LED to keep it on when operating at low secondary currents.

Tom Gallant
- Long Beach, California, USA
2004

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Dear sirs,

I need to develop and manufacture power supply for copper plating that has to be 0-20V/10A, and it has to have voltage/current regulation. I was thinking that it can be done using phase controlled switch (using triac) on primary side of transformer. I think with this way I can control effective voltage that goes on to plating tank, but I don't have a clue how to establish current regulation?! and I'm confused how to connect triac on side transformer at positive line or negative line of main power (220v/50Hz)? and the reason is why like that?

So if you have any idea or schematic please share it with me so I can continue.

Thank you very much in advance.

Dwi Koentjoro Djati
- Surabaya, East Java, Indonesia
2004