Power supply follow up question: Attention Fibergeek

[Gabourie]

power supply

Well thank you for your help with the power supply issues. I have built a holder with a selection of resistors and a fan to keep them cool. So I have come to realize that I am going to be living with the resistors. At the lower current settings it makes the meter very constant and able to control it easier. So yes it may have been a blessing in disguise.
I have since found out that 99% of my problems have been using the wrong information to set the power supply in the first place. The manual I found has a lot of discrepancies that are at the cause. The biggest is the setting for ACID copper. Should read 1 amp for every 16 sq" not 1 amp for 10-30 sq".
It is great, using correct info

[Fibergeek]

OK, this is what I have:

I simulated a highly conductive electroplating setup by using almost a dead short across the power supply terminals. The resistance was what 3 feet of 14 AWG wire and two banana plugs provided, about 0.02 Ohms. Low value high wattage power resistors were than added in 0.05 Ohm increments until the power supply would start up properly.

HY1503D (3A CC/CV rectifier)

Will not start with less than 0.2 Ohms in series.

HY3020E (20A CC/CV rectifier)

Will not start with less than 0.5 Ohms in series.

For reference, I also did the same tests on a $1200.00 Xantrex XHR100-10. This is a professional 1,000 Watt CC/CV offline switcher.

Starts with the almost dead short as described above.

Also tested was 500W CC/CV switcher of my own design.

Starts with the almost dead short as described above.

I took the cover off the 20A CC/CV rectifier, it is also an offline switcher, but nowhere near as sophisticated as the Xantrex.

Something you should know about off line switching power supplies; the 120 VAC is rectified and applied to the circuit directly, it is not reduced to a lower voltage with a transformer as in linear power supplies. The necessary isolation transformer is further down stream in the circuit. This means there is 204 - 374 VDC present and at more than enough current to kill you instantly. Don't open them up!.

I expect the 3A rectifier is also a switcher. Both of these are much better than I was expecting for the price.

In Gabourie's case; 5.3V @ 9.4A is 0.56 Ohms, and 3.8V @ 10.6A is 0.36 Ohms.

[Fibergeek]

Thank you Bill, we'll get this sorted out. Your assistance would be useful and appreciated.

[bhhodges]

The real irony here is that you will likely completely avoid many of the problems you read about here; thin plating, tarnished plating, no plating, inconsistent plating, etc. This is because resistor hassles aside; you actually have far better control of the plating current than any concoction of batteries, battery chargers, light bulbs, nichrome wires, salt water, etc.



great response , i couldnt have said it better myself------------------



bill

[Fibergeek]

I'm going to measure the power supplies tomorrow (Sunday).

What could be the case (I don't know) is that you may be the only one here using these supplies for electroplating. The anodizing guys like them just fine.

The increase voltage that you see is what is dropped across the resistor, the plating doesn't see it, it will have no adverse effects. The plating only "sees" the voltage that corresponds to the current you pass through it for the resistance it has at the moment (this changes as the plating forms). This is nothing more than Ohm's Law.

The real irony here is that you will likely completely avoid many of the problems you read about here; thin plating, tarnished plating, no plating, inconsistent plating, etc. This is because resistor hassles aside; you actually have far better control of the plating current than any concoction of batteries, battery chargers, light bulbs, nichrome wires, salt water, etc.

I wouldn't be surprised if your plating is actually great, you just don't know it yet.

[Gabourie]

power supply

That is amazing that I am the only one who has 2 of these power supplies with the same "problem". I bought a second so I could use more than one tank at a time. As I mentioned in another posting that the second one is even more sensitive and it requires a "boost" from a resistor then I can remove it some times to keep the unit going in flash copper as well as in the nickel. I have been using them both quite a bit in the 10 amp range as well as down to 2 amps. up to 15amps on one part. I was getting a reading of 5.3 volts at 9.4 amps in the acid copper. 3.8 volts and 10.6 amps in flash copper (resistor removed after start up) . Not having much to compare to, I think it is plating ok? I can live with the tolerances on the read out. I am just still wondering about the start up. I am also not sure what the increased voltage will do to the plating results? Any idea?
The power supplies work great after start up. So the range would be start up. I would be more than happy to explain my set up. Where should I start?

[Fibergeek]

I have one of Caswell's 3A and a 20A CC/CV rectifiers right now. I will get to measuring them shortly. Are you still using these for very low voltages and low currents? Can you give me some voltage and current numbers where his problem occurs?

You can easily confirm the voltage readings on the power supply read outs. Measure across the PS outputs with a multimeter and see if they agree. The readouts can be adjusted (?) by a pot internal to the unit if the reading is off. But not the "threshold" to start up, this in inherent in the design.

If you read the User's Manual that came with the PS, under "Technical Parameters" you will see that the manufacturer won't sign up to any regulation below 6 mV (0.006 Volts) or any current below 3 mA (0.003 Amps) they say nothing about startup at very low settings. The readouts can also be as much as "2 digits" off". What they're trying to say in Chinese English is that the right-most digit could read a "3" when the real number is "1". In other words, off by 0.02 Amps or 0.2 Volts maximum.

Mike Caswell has told me that you are the first and still the only one experiencing this problem. I'd like to know more about exactly what you are doing.

The better way is a real laboratory grade CC/CV power supply. Go check the prices on these, you'll see. What you have really is seriously inexpensive, actually dirt cheap compared to the alternatives.

[Gabourie]

I know we are all very busy, but I was wondering if you have had an opportunity to test any of the power supplies. I was encountering a small efficiency problem so I bought another power supply to be able to use more than one tank at a time. Well guess what? It is even more sensitive.
Having to use a resistor to get it to start, I have found that the voltage is now higher on the meter, will that effect the plating process? In the flash copper as well as Nickel, I can get the unit to start with the resistor then I take it out of the circuit and it stays on. It is like there is a threshold limit then once it is on the unit stays on? I have read many of the posting on this forum and I have not seen any that mention a start up "problem". I am getting use to using a resistor. I just wish there was a better way? Obviously this would not be something suggested , but could it be something as simple as adjusting a "pot" on the board to make it not as sensitive? Even though you get what you pay for, they are not that cheap.