Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > General Electronics Technical Discussion
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 07-11-2006, 09:46 PM   #1
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 3,021
Default Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Tech Tutorial: Choose the correct capacitors for reliable automotive applications
While not as glamorous as microprocessors or DSPs, passives, such as capacitors, must still have reliability for auto use
By Dave Richardson, Vishay Intertechnology
Automotive DesignLine
(07/07/2006 4:09 PM EDT)
Quote:
Selecting the most reliable capacitors for today's automotive electronics requires the design engineer to examine a number of different device parameters and performance characteristics. The next step is to consider the automotive environment in which the electronics will be used and the specific applications for which they are intended. Here is a look at the characteristics of the four major dielectric types of capacitors-tantalum, aluminum electrolytics, poly-films, and ceramic; an explanation of the concepts of temperature and voltage coefficients of capacitance; and how these and other factors affect the choice of capacitor for a given application.
__________________
PeteS in CA

Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.

Where might is right
There is no right.
- Sophocles in "Antigone"
****************************
All that is gold does not glitter,
Not all those who wander are lost;
- J.R.R. Tolkien, The Fellowship of the Ring
****************************
To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
PeteS in CA is offline   Reply With Quote
Old 07-19-2006, 07:12 AM   #2
Super Nade
Badcaps Veteran
 
Join Date: Jun 2006
Posts: 293
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

I didn't know Vishay Dale made caps? I know they make other passive devices like resistors, chokes, inductors etc...

Thanks mate. That was quite informative.
__________________
Quote:
Q6700 @ 3.6 GHz
Zippy GSM-6600P
Curcial Ballistix PC6400 (4 x 1Gb) Micron D9GMH
Abit IP35Pro
ATi HD4870
Super Nade is offline   Reply With Quote
Old 07-19-2006, 04:36 PM   #3
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 3,021
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Vishay is a gigantic conglomerate of bought-up companies or parts of companies. Most divisions do passives; those that make caps are BCcomponents, Cera-Mite, Roederstein, (part of) Sprague, Vitramon. Not sure whether the piece of the original Sprague does tantalums, films, or some Al Els.
PeteS in CA is offline   Reply With Quote
Old 11-15-2020, 09:02 AM   #4
linuxguru
Badcaps Veteran
 
Join Date: Apr 2005
Posts: 1,364
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

* 14-year bump *

Vaguely related: I found a small stash of Elna RKB automotive electrolytics with nice specs: 1000 uF / 35V / 12.5 mm / 1880 mA ripple current / 135 c/ 3000 h.

http://www.elna.co.jp/en/capacitor/a.../pdf/rkb_e.pdf

It's the combination of high ripple current, temperature and endurance that makes it interesting. Measured ESR was not too shabby either at 30 mohm - these would be great for SMPS recaps, and would probably survive fan failures.
linuxguru is offline   Reply With Quote
Old 11-20-2020, 11:58 PM   #5
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 9,854
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Very interesting find, linuxguru.

Indeed 135C -rated caps should probably soldier through a fan failure. However, if the temperatures inside the PSU start going above 100C, I suspect many of ferrite core components will probably start loosing their properties, so the PSU will probably fail again. But at least it's good to know you may not have to do a full recap after a fan failure.
momaka is offline   Reply With Quote
Old 11-21-2020, 05:35 AM   #6
Per Hansson
Super Moderator
 
Per Hansson's Avatar
 
Join Date: Jul 2005
City & State: ----
My Country: Sweden
Line Voltage: 230v 50Hz
I'm a: Knowledge Seeker
Posts: 4,586
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

When the fans fail in cheap power supplies what happens is that the primary side transistors desolder themselves as they get too hot and the PSU explodes, ask me how I know
And yes, this may save both the caps and fuse, not sure much else survives though
I think the proper solution is to have the damn PSU shutdown when the heat sinks become 100C but what do I know since I'm not a PSU designer?
__________________
"The one who says it cannot be done should never interrupt the one who is doing it."

Last edited by Per Hansson; 11-22-2020 at 03:59 AM.. Reason: spelling
Per Hansson is offline   Reply With Quote
Old 11-21-2020, 03:53 PM   #7
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 3,021
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Quote:
Originally Posted by linuxguru View Post
* 14-year bump *
...
As soon as I saw the thread title and didn't remember I'd posted it I knew it had to be quite a while ago.
PeteS in CA is offline   Reply With Quote
Old 11-21-2020, 04:02 PM   #8
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 3,021
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Quote:
Originally Posted by Per Hansson View Post
When the fans fail in cheap power supplies what happens is that the primary side transistors desolder themselves as they get too hot and the PSU explodes, ask me how I know
...
Long, long ago when I worked at Boschert we built up a prototype of a 750W P/S. We didn't have the inrush thermistors we needed, so we installed what was used in Boschert's OL400 series, 400W. We ran the proto at load overnight and when we came in the next morning we found that the thermistors had run so hot that they desoldered themselves and, being positioned upside down, had fallen out of the PCB.
PeteS in CA is offline   Reply With Quote
Old 11-23-2020, 09:43 PM   #9
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 9,854
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Hey, that sounds like a new method of circuit protection. Just install a thermistor or whatever else with leaded (or maybe even low-melt temperature solder) and if it desolders itself, the device ran too hot. Sounds like a good way to prevent parts from blowing IMO.
momaka is offline   Reply With Quote
Old 11-24-2020, 02:02 PM   #10
Per Hansson
Super Moderator
 
Per Hansson's Avatar
 
Join Date: Jul 2005
City & State: ----
My Country: Sweden
Line Voltage: 230v 50Hz
I'm a: Knowledge Seeker
Posts: 4,586
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Well if the PSU manufacturers are unable to come up with a logic based solution I have an idea for them:
Use a mechanical temperature based switch on the live wire, automatically switches PSU off when temperature gets up to its rating
Per Hansson is offline   Reply With Quote
Old 11-24-2020, 06:03 PM   #11
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 3,021
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Quote:
Originally Posted by Per Hansson View Post
Well if the PSU manufacturers are unable to come up with a logic based solution I have an idea for them:
Use a mechanical temperature based switch on the live wire, automatically switches PSU off when temperature gets up to its rating
Boschert used to have thermal switches on the L-brackets of many of their OL series power supplies. Back in ancient times ....
PeteS in CA is offline   Reply With Quote
Old 11-25-2020, 05:35 PM   #12
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 9,854
Default Re: Tech Tutorial: Choose the correct capacitors for reliable automotive applications

Quote:
Originally Posted by Per Hansson View Post
Well if the PSU manufacturers are unable to come up with a logic based solution I have an idea for them:
Use a mechanical temperature based switch on the live wire, automatically switches PSU off when temperature gets up to its rating
That's a pretty good idea.

Actually, a lot of appliances with heaters inside (like your clothes iron, for example) already have thermal switches like that. The idea is that in case the bi-metallic switch fails, the thermal switch will open and disconnect power, thus preventing a possible fire.
momaka is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 04:25 AM.
Did you find this forum helpful?