Balanced F5 question

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Sometimes it's worth looking carefully first. ;)

There is no reason to have to have TS-HA.
Some 85°C caps lives very long, unless you are listening to music over 8 hours everyday.
And the two ends of the heatsink are hardly over 50°C, near to which is the caps are placed, to the immediate left & right of the main PCB.

Take a look at the lifetime specified for e.g. Vishay BC 056 series (85°C) :

VISHAY BC COMPONENTS|2222 056 46223.|CAPACITOR, 22000UF 25V | Farnell United Kingdom
http://www.farnell.com/datasheets/15301.pdf

"Useful life 85°C 12000 hrs."
"Useful life 40°C 210000 hrs."


For EPCOS, you may choose B41231A5339M000 :
https://www.buerklin.com/datenblaetter/D097790_TD.pdf
http://www2.mouser.com/ProductDetai...=sGAEpiMZZMtZ1n0r9vR22flQyDdOCPaozkPvoelrzp0=

which is 33000uF and has one of the highest ripple current at 120Hz that I have seen for that size.


Patrick

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At a glance.
Feel free to propose more alternatives.


Patrick
 

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question is, are 105 C any better than 85 C, if temperature stays below 60 C at all times :confused:

but BC 105 C have slightly larger diameter than 85 C

are they double shielded, or is it because they hold more electrolytic, or both ?
is it about cooling, or purely chemical, or both ?

My friends that work at boeing, say "never use 85 degree caps for power supplies". They are constantly pulling out failed 85 degree caps and replacing them with 105 degree parts.
They have never had to replace a 105 degree rated cap (except in the case where the caps were over 20 years old).

The rated capacitance also tends to drop more with heat in the 85 degree parts.

If you can get them cheap I wouldn't hesitate in using them but if the price difference is small go for the 105 degree parts.
 
All,

Just wanted to let those in the first transformer buy know that all payments have been received and production will begin at SumR for these. Once complete, we will receive notice and I will post here so that everyone knows they are on thier way. Many thanks to SumR for the support and product.

Dave
 
Hi Patrick could you give some back ground on these graphs.

It looks like for 85 degree caps at 2A and 60 degrees you get 12000 hours of life.
And for 105 degres caps at 2A and 60 degrees you get 100000 hours of life - that's almost an order of magnitude better (ie about 10x better).
This seems to agree with what my friends have been saying about 85 degree caps (crap).

Thanks Patrick for digging this up.
 
Thanks Patrick

OK it looks like, for 85 degree caps 50000 hrs at 60 degrees at max rated ripple current (I/I =1)
And for 105 degree caps somewhere between 250000 hrs and 100000 hrs at 60 degrees and max rated ripple current (I/I=1)
So, somewhere between 2 and 5 times better for 105 degree caps at max rated ripple current and same operating temp (60 degrees). This seems about right
And about 8 to 10 times better for 105 degree caps at double max rated ripple current and same operating temp (60 degrees).
 
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Best 25V TS-UQ with dimensions 30mm x 50mm, 47000uF has 8A ripple current at 85 degrees

Best 25V TS-HC with dimensions 30mm x 50mm, 39000uF has 5.8A max rated ripple current at 105 degrees

Trying to make sense of all of this. Let's say we run both caps at 5.8A at 60 degrees.
That will be I/I=1 for TS-HC and I/I=0.725 for TS-UQ.

So, TS-UQ will give somewhere between 100000 hrs and 50000hrs of life at 5.8A and 60 degress.
And, TS-HC will give somewhere between 250000 hrs and 100000 hrs of life at 5.8A and 60 degrees
 
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