Generate 100amp "fuse test" current? - Page 1
Forum section: electronics / projects

author: max_torque
author_rank: Super Contributor
timestamp: April 02, 2017, 05:11:23 pm
content: What do people reckon is the cheapest / easiest way of generating a 100amp continuous (say for 2 to 4 hrs) current to test a fusing system? The burden voltage is pretty low (probably around 1v, due to the 10mOhm resistance) so total power is low (~100W)Two options seem possible, a cheap 3.3V switch mode psu (like a server supply) or a large Step down 50Hz transformer into a number of parallel rectifiers / cap bank.In both cases current limitation might have to be done by a passive resistor (ive used coiled copper pipe with water flowing through it before, more copper length = less current). Exact current is not that important as i will be measuring the actual current throughout the test.Thoughts anyone?

author: bktemp
author_rank: Super Contributor
timestamp: April 02, 2017, 05:14:14 pm
content: 1V 100A sounds like a typical CPU core voltage.A multiphase stepdown is probably the easiest solution, using 5-12V input voltage.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 02, 2017, 05:14:56 pm
content: DC? It has to be DC?Why not a toroidal transformer with a single turn (welding cable) secondary and a variac to control it?Tim

author: Jeroen3
author_rank: Super Contributor
timestamp: April 02, 2017, 05:28:18 pm
content: With a rotary converter, current limiting exciter regulator (also knowns as avr) and a bridge rectifier.

author: max_torque
author_rank: Super Contributor
timestamp: April 02, 2017, 06:17:35 pm
content: Current needs to be DC yes

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 02, 2017, 06:19:59 pm
content: Consider using a choke-input filter, and current-doubling rectifier, instead. Hammond may have some chokes available in that size.Otherwise, any low voltage, high current, adjustable power supply will do the job. There are plenty to choose from, and anyway, you'll want the safety and quality assurance of a proper piece of lab gear that can be calibrated regularly.Tim

author: Seekonk
author_rank: Super Contributor
timestamp: April 02, 2017, 06:28:03 pm
content: Look around ebay. I have a 150A 5V analog power supply that can barely be given away these days. Putting a buck transformer on the high current transformer and a couple mods would make this fairly efficient.Wind your own? Look here for some ideashttp://www.fieldlines.com/index.php/topic,148717.0.html

author: nctnico
author_rank: Super Contributor
timestamp: April 02, 2017, 06:57:04 pm
content: I'd get a lab PSU from Ebay.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 03, 2017, 03:21:49 am
content: Quote from: max_torque on April 02, 2017, 05:11:23 pmI have a couple of small supplies I use for higher currents in this range. I have a 20ppm shunt that I use for feedback to control the voltage to get my constant current. It all connected to a PC and I use LabVIEW to run it. No water filled copper pipes.You can get an idea from the couple of links below.https://youtu.be/ne4Ls2mPF-s?t=171https://youtu.be/ns02v6ebCGU?t=454

author: grifftech
author_rank: Frequent Contributor
timestamp: April 03, 2017, 03:29:09 pm
content: rent an arc welder

author: max_torque
author_rank: Super Contributor
timestamp: April 03, 2017, 06:49:57 pm
content: Quote from: joeqsmith on April 03, 2017, 03:21:49 amAre you controlling the output voltage of those supplies to control the current?