Current / Voltage regulation

[James]

okay - quick one here - i have a power supply that someone gave to me.

current rating...0.5A to 50Amp

volage ranges...1-7.5v , 6-15v , 6-30v , 31-60v.

I know its a beast but I need a high amp for an anodising station. My
question is is how hard is it to build a current / voltage reg circuit for
something like this? Can someone help me out with a circuit or point me in
the right direction?

 

[Repeating Rifle]

okay - quick one here - i have a power supply that someone gave to me.

current rating...0.5A to 50Amp

volage ranges...1-7.5v , 6-15v , 6-30v , 31-60v.

I know its a beast but I need a high amp for an anodising station. My
question is is how hard is it to build a current / voltage reg circuit for
something like this? Can someone help me out with a circuit or point me in
the right direction?

From my meager knowledge of plating electrochemistry. only the low range
will be of interest to you unless you put a number of your plating vats in
series. That is done in the aluminum smelting industry.

What are your regulation reqirements and why? I would guess that a single
transformer with thyristor phase control would be good enough. Polyphase
rectifiers would be better if ripple were a problem. Because of the low
electrochemical voltages used, semiconductor drops will lower efficiency if
vats are not in series.

Bill

 

[James]

I was thinking - could i just use various 1ohm say 25W resistors inline with
the + to vary this?

 

[Tim Perry]

I was thinking - could i just use various 1ohm say 25W resistors inline with
the + to vary this?


me

you already have voltage control... so just add a series load to put the
current about where you want it. i have used light bulbs and electric oven
elements as high power resistors. even a space heater in series might work.
auto headlights for low voltage work might be what you want.

but as you say the current rating is .5 to 50A does that mean it has
adjustable limiting? (otherwise the current would be 0 to 50)

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

okay - quick one here - i have a power supply that someone gave to me.

current rating...0.5A to 50Amp

volage ranges...1-7.5v , 6-15v , 6-30v , 31-60v.

I know its a beast but I need a high amp for an anodising station. My
question is is how hard is it to build a current / voltage reg circuit for
something like this? Can someone help me out with a circuit or point me in
the right direction?

If the minimum current is .5A, then put a resistor across the output to
deaw at least that much. R = E/I.

To limit the current, just get some high current lamps like 12V
headlamps and put them in series with the + output lead. One headlamp
might be 20A, so put another across it with a switch so you can have 20A
or 40A. You could use smaller lamps for less current, each with a
switch. Voltage isn't a problem, as others stated you will probably
need the low voltage range.

 

[Tzortzakakis Dimitrios]

It HAS a current reg circuit (or should have).Does it have knob(s) labelled
voltage, current or smthg.like that?Does it have gauges?It's not a
beast.Real beasts are aluminium industries, that make aluminium out of
bauxite (the most power-hungry industry probably).They are linked directly
to the HV grid (150 kV here).Also >7,5 MVA (which is the largest MV supply
available here).

 

[Don Kelly]

It HAS a current reg circuit (or should have).Does it have knob(s) labelled
voltage, current or smthg.like that?Does it have gauges?It's not a
beast.Real beasts are aluminium industries, that make aluminium out of
bauxite (the most power-hungry industry probably).They are linked directly
to the HV grid (150 kV here).Also >7,5 MVA (which is the largest MV supply
available here).

----------
Actually aluminum smelters (specifically those that I am familiar with)
run at 600 to 1200 VDC and 50 to 100MVA per potline .
Sure the incoming lines are at 150 or higher KV but this is stepped down to
the 13-15 KV level then at each line dropped down again to the lower voltage
and rectified. Depending on the potline (and when it was built) the current
may be 50,000 to 100,000 Amps.
Your "beast" is quite small.

 

[SQLit]

----------
Actually aluminum smelters (specifically those that I am familiar with)
run at 600 to 1200 VDC and 50 to 100MVA per potline .
Sure the incoming lines are at 150 or higher KV but this is stepped down to
the 13-15 KV level then at each line dropped down again to the lower voltage
and rectified. Depending on the potline (and when it was built) the current
may be 50,000 to 100,000 Amps.
Your "beast" is quite small.

snipped

I worked on an steel smelter in Vera Cruz Mexico, an 200 MVA plant. Do not
know the primary or secondary voltages, just that you could FEEL the arc
from 200 yards away.

 

[Repeating Rifle]

I worked on an steel smelter in Vera Cruz Mexico, an 200 MVA plant. Do not
know the primary or secondary voltages, just that you could FEEL the arc
from 200 yards away.

The main point of using an electrical furnace for steel is to obtain heat in
a clean way. an ac arc is probably ok although I do not really know.

For aluminum, the electrical energy is REQUIRED for electrolytic reduction
of aluminum in solution. To some extent, the carbon electrodes help in the
reduction process by combining with oxygen, but carbon is not a suffiently
strong reducing agent without a boost from electricity. Aluminum was first
produced using potassium or sodium as reducing agents. Those, produced
electrolytically themselves, would not require an electrical boost.

Bill