Author Topic: Is it OK to salvage electrolytic caps from switchmode PSUs?  (Read 269 times)

Offline Zipdox

  • High Voltage Technician
  • ***
  • Posts: 133
  • Karma: +1/-0
    • View Profile
    • Zipdox
Is it OK to salvage electrolytic caps from switchmode PSUs?
« on: August 21, 2020, 11:22:24 PM »
What the title says. More specifically, computer PSUs. Is it OK if I just test their capacitance or something?
« Last Edit: August 21, 2020, 11:47:39 PM by Zipdox »

Offline davekni

  • High Voltage Senior
  • *****
  • Posts: 853
  • Karma: +39/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Is it OK to salvage electrolytic caps from switchmode PSUs?
« Reply #1 on: August 22, 2020, 03:50:20 AM »
Generally, yes.  Depends on supply age and use history and how much margin was in the design.  Electrolytic caps used to the edge of their rating for extended time do wear out.  Primary change is higher ESR (equivalent series resistance).  Caps are often rated as end-of-life being 3x initial ESR, so quite significant change.  If your planned use involves high ripple current, ESR is of particular concern.

Also, if the supply has been sitting idle for years, it's best to reform the caps internal oxide layer gently.  Charge slowly once by limiting current to a few mA.  Larger caps usually have specs for reforming current.  I've gotten away with mostly ignoring this reforming requirement except on really large caps.  (I think the consequence of fast charging after long idle is creating leakage current paths, which probably lead also lead to higher ESR as electrolyte decomposes.)
David Knierim

High Voltage Forum

Re: Is it OK to salvage electrolytic caps from switchmode PSUs?
« Reply #1 on: August 22, 2020, 03:50:20 AM »

 


* Recent Topics and Posts

post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
Today at 06:37:53 AM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
davekni
Today at 06:16:41 AM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
Today at 05:00:50 AM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
davekni
Today at 04:03:12 AM
post Just a noob with some HV concerns...
[Beginners]
MrScrOggs
Today at 03:07:11 AM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
Today at 02:57:27 AM
post Re: compact midi interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
Today at 12:06:44 AM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
davekni
January 18, 2021, 11:56:31 PM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
Alberto
January 18, 2021, 11:50:22 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
klugesmith
January 18, 2021, 10:30:15 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 18, 2021, 10:03:46 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
davekni
January 18, 2021, 09:58:44 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 18, 2021, 08:52:29 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
davekni
January 18, 2021, 07:08:09 PM
post Re: Adding interrupter Self oscillating tesla coil
[Beginners]
davekni
January 18, 2021, 06:49:28 PM
post Re: Alcatel Lucent B4 RRH2x60-4R teardown and reverse engineering
[Radio Frequency]
Da_Stier
January 18, 2021, 06:12:44 PM
post Re: Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
klugesmith
January 18, 2021, 04:53:23 PM
post Adding interrupter Self oscillating tesla coil
[Beginners]
arto
January 18, 2021, 11:54:54 AM
post Re: Segmented PTFE Secondary, Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 18, 2021, 08:27:18 AM
post Re: Self Oscillating Half Bridge Wonder
[Solid State Tesla Coils (SSTC)]
Acid Byte
January 18, 2021, 06:57:06 AM
post Re: Segmented PTFE Secondary, Plasma Ball project
[Transformer (Ferrite Core)]
davekni
January 18, 2021, 06:43:19 AM
post Re: Segmented PTFE Secondary, Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 18, 2021, 05:48:27 AM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
klugesmith
January 18, 2021, 01:03:48 AM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
Alberto
January 18, 2021, 12:26:26 AM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
davekni
January 17, 2021, 11:29:04 PM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
Alberto
January 17, 2021, 09:55:24 PM
post Re: Segmented PTFE Secondary, Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 17, 2021, 09:34:21 PM
post Re: Segmented PTFE Secondary, Plasma Ball project
[Transformer (Ferrite Core)]
davekni
January 17, 2021, 08:51:50 PM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
davekni
January 17, 2021, 08:04:54 PM
post Re: compact midi interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
tophat
January 17, 2021, 05:40:59 PM
post Re: Schlieren images projected onto a wall (no camera)
[Light, Lasers and Optics]
Uspring
January 17, 2021, 05:12:45 PM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
SteveN87
January 17, 2021, 02:20:09 PM
post Re: First SSTC build - some questions
[Solid State Tesla Coils (SSTC)]
zytra
January 17, 2021, 05:56:05 AM
post Segmented PTFE Secondary, Large Plasma Ball project
[Transformer (Ferrite Core)]
zytra
January 17, 2021, 05:55:11 AM
post Re: First SSTC build - some questions
[Solid State Tesla Coils (SSTC)]
davekni
January 17, 2021, 03:50:27 AM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
davekni
January 17, 2021, 03:37:28 AM
post Re: First SSTC build - some questions
[Solid State Tesla Coils (SSTC)]
zytra
January 17, 2021, 01:48:10 AM
post Re: how to run these guys?
[Transformer (Ferrite Core)]
Alberto
January 16, 2021, 11:21:13 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 16, 2021, 10:09:21 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Miki_407
January 16, 2021, 09:38:08 PM
post Re: Schlieren images projected onto a wall (no camera)
[Light, Lasers and Optics]
davekni
January 16, 2021, 09:27:25 PM
post Re: UD2.9 Troubleshooting Help
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 16, 2021, 09:05:23 PM
post Re: UD2.9 Troubleshooting Help
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
January 16, 2021, 07:44:41 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 16, 2021, 07:06:13 PM
post Re: UD2.9 Troubleshooting Help
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 16, 2021, 06:48:05 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Miki_407
January 16, 2021, 06:38:11 PM
post Re: UD2.9 Troubleshooting Help
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
January 16, 2021, 06:23:53 PM
post Re: Schlieren images projected onto a wall (no camera)
[Light, Lasers and Optics]
klugesmith
January 16, 2021, 06:23:10 PM
post Re: UD2.9 Troubleshooting Help
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GKnapp
January 16, 2021, 03:28:14 PM
post Re: First SSTC build - some questions
[Solid State Tesla Coils (SSTC)]
davekni
January 16, 2021, 05:09:53 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal