voltage spike when ps is turned on - Page 1
Forum section: electronics / beginners

author: busta9
author_rank: Newbie
timestamp: March 01, 2014, 02:05:04 am
content: Hello,I have a variable 0-15 Vdc power supply (model: HY1503C). When I turn it on and the voltage and current are turned all the way up there is a voltage spike and it outputs almost 18V for a split second which is damaging some equipment. I have tried a few things but have not been able to find a solution to manage this spike.Is there a way I can limit/block/redirect the spike to protect the electronics it is powering?Thanks so much.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 01, 2014, 02:15:50 am
content: What happens when the voltage control is turned down?If that limits the spike to a safe value,why not adjust the output to the correct level after you turn the supply on?

author: busta9
author_rank: Newbie
timestamp: March 01, 2014, 02:20:20 am
content: That is the easy solution and it does work. Unfortunately, there are many people that use this system and not everyone follows the rules. I am looking for a way to make this fool proof without changing the power supply.Thanks for your reply.

author: SeanB
author_rank: Super Contributor
timestamp: March 01, 2014, 05:02:01 am
content: Output relay with a simple delay. Add relay with enough changeover contacts to switch all output sockets, and use a simple rectifier direct on the secondary of the transformer with a RC delay to give a half second turn on delay. If there is a voltage of around 18V-20V use a diode and a 100R 1W series resistor to charge a 470-1000uF 35V capacitor and connect a high sensitivity 24V relay across the capacitor. Will give a short delay on power on before connecting the output. If you add a resistor of 100R or so across the NC contacts as well and feed the PSU output to the moving contacts it will attenuate the pulse internally as well so you have no spike from any output capacitors as well.

author: pickle9000
author_rank: Super Contributor
timestamp: March 01, 2014, 05:12:26 am
content: SeanB 's idea is simple and works, I have done it in the past and it's easy.You may want to have a look at this. I don't know if you have a supply like this but it's a fairly common problem on chinese supplies.

author: busta9
author_rank: Newbie
timestamp: March 01, 2014, 04:36:14 pm
content: Thanks for the reply. I was actually thinking about using a relay with some sort of time delay but was not sure how to go about it. I will try this out and let you know how it worked. Thanks again

author: Zero999
author_rank: Super Contributor
timestamp: March 01, 2014, 06:20:54 pm
content: Try connecting a large 16V zener diode and capacitor across the output terminals.

author: amtpdb
author_rank: Regular Contributor
timestamp: March 01, 2014, 10:29:46 pm
content: I purchased 2 of these power supplies last month, 3010D but different branding. I have watched this video twice, once before and then after buying them. I was hoping that the video maker would respond with the points that he hooked the capacitor up to and the size capacitor but he has not. Does anyone know to what points and what size capacitor he (or what have you installed) installed to fix the issue? Which of the plugs have you replaced the front plugs with and are happy with them. I am a hobbyist and don't have a lot of money to waste buying the wrong pieces and just trying to pick up supplies. I would like to fix these units if I can.Thanks in advance for any help, information or suggestions.Don