Power Supply overload protection - Page 1
Forum section: electronics / beginners

author: triond
author_rank: Newbie
timestamp: June 24, 2015, 11:36:06 pm
content: Hii was looking for power supplyin this case this onehttp://www.dx.com/p/sanpu-s250-super-thin-12v-250w-20-8a-led-power-supply-silver-294784#.VYs1Dfl_P1Gwhen i read itits say short circuit, over load / voltage protectionand this remind me a power supply i have been using for doing some electrolisiswhen the salt solution is too concentrated the power supply stop and won't do anything until i replug the power supplysame when there a short circuit directly from the output wirei was wondering how that feature work and is there a way to bypass it ?

author: Mr.B
author_rank: Unknown
timestamp: June 25, 2015, 12:00:05 am
content: You certainly don't want to bypass it.The over current protection is there to protect the power supply.I am sure you don't want to burn your house down...Depending upon your application, you may need to buy a power supply that can deliver more current.Edit:You haven't told us your application so I probably shouldn't comment...

author: triond
author_rank: Newbie
timestamp: June 25, 2015, 12:07:55 am
content: so i should make some ajustement to the electrolitic cell to be balanced at a level the power supply can workso the power load could be in direct correlation with the resistance between the electrode ?

author: Mr.B
author_rank: Unknown
timestamp: June 25, 2015, 01:04:49 am
content: I don't know enough about the electrolysis of water to make any recommendations.There are other far more qualified people here that may be able to help.I strongly suggest you do more (internet) research on the Voltage, Current and Electrode requirements.

author: Wim_L
author_rank: Regular Contributor
timestamp: June 25, 2015, 11:22:01 pm
content: Moving the electrodes further apart should lower the cell current.

author: jeroen79
author_rank: Frequent Contributor
timestamp: June 26, 2015, 08:54:22 am
content: Or get a powersupply that goes to constant current mode instead of simply shutting down when loaded too much.

author: ivan747
author_rank: Super Contributor
timestamp: June 28, 2015, 01:18:43 pm
content: Quote from: jeroen79 on June 26, 2015, 08:54:22 amThis is the best solution for electrolysis. In fact, if I remember correctly, some electrolysis equations regarding reaction time used involved current and not voltage (well, they involve voltage indirectly, but the calculations will get messy). Keeping a constant current would make it much easier and predictable.Sent from my XT1063 using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: June 28, 2015, 01:47:50 pm
content: While you need a certain voltage to overcome the electrode potentials before current will flow in the desired direction, and more voltage to get enough current flow due to solution's resistivity, *ALL* electrolysis reactions are current driven.The simplest way of managing an electrolysis cell is with a voltage limited constant current power supply, then, for unattended operation, use a window comparator monitoring the voltage across the cell to detect significant changes of the cell voltage from its normal operating point and sound an alarm.The poor-man's way of managing it with a constant voltage PSU is to add a ballast resistor in series with the cell to limit the current. One or more incandescent bulbs in parallel make excellent ballasts as their cold resistance is typically ten times less than their hot resistance so the voltage drop is small unless the current rises significantly.I'd go with several 12Vuniversal halogen bulb socketsin parallel, then fine tune the current by plugging in different wattage bulbs. Do check that the PSU can power up and light all the bulbs with the cell shorted without tripping, which usually means you cant use all the PSU's wattage as a reserve is needed for the startup surge.