How to use Longwei DC Power Supply LW-K3010D

JoanC

New member
Hi, I have done electrolysis before successfully before burning out two battery chargers so I bought the DC Power Supply recommended on this site. However, I do not understand how to use it. For starters, I do not know which method to use: constant current or constant voltage. The constant current method entails making a short circuit and that doesn't seem right. If we chose the contact voltage mode, we get the voltage to maximum but the current cannot be changed and it seems to have no indicator number. Would greatly appreciate any detailed, step--by-step explanation of how to use this device. Thank you.
 
Current is what counts in an e-tank. Setting the current by shorting the output is the normal way to adjust a CC (constant current) supply. The voltage will be what it is depending on the load resistance due to ohms law. E=IR. The voltage will be very low when setting the current because the resistance of the short will be very close to but not quite zero ohms.

That being said, the way to set up your e-tank power supply is to set up your tank as normal with the piece in it, turn on the supply, set the voltage to maximum and adjust the current to what ever you want it to be. Ignore the displayed voltage. Higher current is generally faster but will generate more heat in the tank and any connections. A CC supply is convenient in that it will tolerate very low resistance loads. The resistance of your e-tank depends on a number of factors. These are
1) strength / composition of your electrolyte
2) Anode area
3) Cathode (parts to be cleaned) area
4) Distance between anode and cathode
5) Resistance in connections to anode(s) and cathode(s) i.e the wire to the piece being cleaned

FWIW, I personally use NaOH as my electrolyte in the same 2.5% w/w concentration that is normally used in a lye tank. This has a couple of advantages for me. One and done tank, and I can use mild steel sheet anodes with out them rusting. This is because the lye neutralizes the locally acidic area around the anode. No need for graphite anodes.

Hope that this helps.
 
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So, do I understand correctly, "normally" for CC you touch the electrodes together with the voltage set to max, dial in the amperage you want, then attach the electrodes to whatever load?
 
Thanks to everyone. We got it to work, more by trial and error than a clearcut method and are still confused about the process. Can someone write out step-by-step how you deal with the machine. For example, you turn power on, plug in the wires, touch the electrodes together (???) then dial the amperage (to what?), then set the voltage (to what?), then attach the clips to the sacrificial metal and leave the machine alone? We noticed this morning that the machine switched from CC to CV but do not know why or if it is important to get it back to CC. Thank you.
 
Did your unit reach the maximum voltage set? Just thinking out loud here but maybe it switches from CC to CV when the voltage to maintain CC exceeds the voltage available.
 
So, do I understand correctly, "normally" for CC you touch the electrodes together with the voltage set to max, dial in the amperage you want, then attach the electrodes to whatever load?
Yes, that is he normal way to set max current on a CC supply.
 
Did your unit reach the maximum voltage set? Just thinking out loud here but maybe it switches from CC to CV when the voltage to maintain CC exceeds the voltage available.
If you re using a CC/CV supply. The supply will limit either the voltage or current to whichever maximum they are set to. i.e if your max voltage is set to 15V and your max current is set to 10A, if the load is 100 ohms, the voltage will be 15V and the current will be 0.15A, in this case voltage is the limiting factor. On the other hand, if the load is 1 ohm, the voltage will be 10V and the current will be 10A, in this case current is the limiting factor.

Here is a nice little diagram showing Ohms law.


Ohm's_Law_Pie_chart.svg.png
 
So you have the machine ON when you attach the electrodes after doing the short circuit. That is, you do not turn it off at any point in this process?
When you say "machine" I assume that you mean the power supply. If so, either way is fine. Less arcing if you set the max current, turn off the PS then connect to the e-tank, then turn on the PS. Doesn't really matter which way you do it. Some would prefer not to see a big arc when you connect it. On the other hand, you can have the e-tank connected when setting the current limit. That's the way I do it. Connect PS to e-tank with piece to be cleaned in it, turn on PS and set to desired current. You can also adjust the current limit during the cleaning process for whatever reason.

This isn't rocket surgery, don't over think it.

Over and out.
 
You forgot: Roger, Wilco...
Yes, I know that is not actually proper radio procedure. :)
I meant what I said.
Over means "clear for you to transmit", out means "Not receiving on this channel anymore"

Roger means "received and understood", wilco means "will comply" neither of which apply in this instance :p
 
Wanted to report that we have finally had success with the Longwei power supply. This is how we did it: 1. With power supply off, clip red and black wire clips together to create a "short." 2. Turn voltage knob to max and current knob to minimum. 3. Turn power on. 4. Turn current knob to max. This should result in slightly more than 10 amperes. 5. With power still on, immediately clip red wire to sacrificial metal and black wire to pan. 6. Insert pan in solution. 7. The "constant current" indicator should be lit throughout the whole process, NOT the voltage indicator. The voltage will fluctuate. Also: it was hard to get the the little alligator clip to stay on the pan, so I used copper wire through the pan handle and hooked the alligator clip to the copper. Thanks to everyone for your help.
 
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