I posted about a year ago about problems I was having with my little 3A power supply? Well I ended up getting a bigger one, 30A-30V because I figured that that was what I needed. Well it was better but still had some of the smaller PS's problems. I did a little experiment the other day plating some heater hose sized tower clamps(4-5 sq" max") and this is what I found...
Bath Temp 90 deg. (1.5 gal solution)
Plating volts 1.5V
About 1" of the 4x8 sheet of anode in the solution.
With the clamp in the solution I was pulling about 2.5A with the anode and
clamp at opposite ends of the tank. With the clamp next to the tank I was
pulling 4.5A.
Then I lowered the whole 4x8 anode into the tank and it pulled 3.3A with the
anode and clamp at opposite ends(almost 1A increase due to the increased
anode surface area I guess). Now the funny part and what my old 3A unit
would do... As I brought the clamp closer to the anode the current increased
to 5.5-6A and then kicked off! The voltage light went out(voltage dropped to
.4) and the current light came on(current dropped to .7). If I moved the
clamp away from the anode the PS would kick back in and voltage and amps
would be restored to 1.5V and 3.3 amps. I then tried this same experiment
with a larger rad hose clamp and it would kick the PS out when the clamp
was only half way across the tank
Have you ever had this happen in any of your plating?
I'm not quite sure what is going on but the best way I seem to be able to
control the current is by the amount of anode and part that is in the
tank(of course increasing the voltage will also increase the current). I did
manage to plate my vacuum actuators(about 120 sq") but that was only because I held the majority of it out of the tank, constantly rotating the part much like a water wheel contacts the water. If I let too much of it contact the solution the current would increase too much and the PS would kick off. Not the most time efficient way to do plating but it worked in the end.
As far as smaller plating jobs I pretty much have them figured out and they turn out great everytime but this bussiness of the PS kicking off has me scratching my head, I mean after all it is a 30V-30A power supply!
Any thoughts or ideas are appreciated.