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best capacitors for high ripple and large capacitance

J

Jamie Morken

Jan 1, 1970
0
Hi,

What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

I was looking at electrolytic's, it would take 3 of these caps to get
15Arms ripple handling:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P7492-ND

that would be 30000uF though! :)

Also that caps 5Arms ripple rating is at 10kHz, would this rating
increase or decrease for 200kHz typically for an electrolytic?

cheers,
Jamie
 
P

Phil Allison

Jan 1, 1970
0
"Jamie Morken"
What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

I was looking at electrolytic's, it would take 3 of these caps to get
15Arms ripple handling:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P7492-ND

that would be 30000uF though! :)

Also that caps 5Arms ripple rating is at 10kHz, would this rating
increase or decrease for 200kHz typically for an electrolytic?


** Take a look at the table that shows the multiplier factor to be applied
for ripple currents at varying ambient temperatures.

Cos you fucking need to.



....... Phil
 
J

Jamie Morken

Jan 1, 1970
0
Phil said:
"Jamie Morken"



** Take a look at the table that shows the multiplier factor to be applied
for ripple currents at varying ambient temperatures.

Cos you fucking need to.

Thanks Phil, also take a look at this:

**Use of temperature ripple current multipliers may limit life to the
hours specified for the maximum operating temperature.

which is 3000hours of operation (125days continuous use), is not enough
for this application.

cheers,
Jamie
 
M

MooseFET

Jan 1, 1970
0
Hi,

What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

A whole bunch of NPO ceramics in parallel is the "best" if you aren't
worried about cost or space.

15A RMS at 200KHz is quite a lot of ripple to put through a single
capacitor.

I've used CDE's 381[huh]R at about 0.5A per every 100uF with some
success. They are worth a look.

[huh] My brain froze there is a character in there
 
P

Phil Allison

Jan 1, 1970
0
"Jamie Morken = Smartarse **** "

Thanks Phil, also take a look at this:

**Use of temperature ripple current multipliers may limit life to the
hours specified for the maximum operating temperature.

which is 3000hours of operation (125days continuous use), is not enough
for this application.


** The operative word is " may " - you fucking, smartarse cunthead.

Long as an electro stays reasonably cool ( ie under 45C) it will last for
many years continuous service.

Why do you think so many SMPS using cheap ( ie no brand) electros have
fans in them - eh ??

But you still have no fucking idea about anything in the world of
electronics,
since you are ONE smartarse fucking **** - right ?


GO DROP DEAD - MORKEN

YOU ARE ONE PATHETIC FUCKWIT




........ Phil
 
H

Hattori Hanzo

Jan 1, 1970
0
Hi,

What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

Those figures appear incorrect. 15A rms ripple figure is a very large
number. Are you sure that the number isn't 15mA?
I was looking at electrolytic's, it would take 3 of these caps to get
15Arms ripple handling:

Actually, to get high ripple, one uses NO caps. To ABATE high ripple,
one uses a cap bank, and /or an RC filter, as long as it still provides
the current requisite of the load circuit.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P7492-ND

that would be 30000uF though! :)

Also that caps 5Arms ripple rating is at 10kHz, would this rating
increase or decrease for 200kHz typically for an electrolytic?

Where do you derive that "ripple figure" from? It is not on the page
you gave a link to.
 
J

Jamie Morken

Jan 1, 1970
0
Phil said:
"Jamie Morken = Smartarse **** "




** The operative word is " may " - you fucking, smartarse cunthead.

Long as an electro stays reasonably cool ( ie under 45C) it will last for
many years continuous service.

Why do you think so many SMPS using cheap ( ie no brand) electros have
fans in them - eh ??

But you still have no fucking idea about anything in the world of
electronics,
since you are ONE smartarse fucking **** - right ?


GO DROP DEAD - MORKEN

YOU ARE ONE PATHETIC FUCKWIT

Sorry Phil, I will remember never to quote from datasheets again :D
 
J

Jamie Morken

Jan 1, 1970
0
MooseFET said:
Hi,

What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

A whole bunch of NPO ceramics in parallel is the "best" if you aren't
worried about cost or space.

15A RMS at 200KHz is quite a lot of ripple to put through a single
capacitor.

I've used CDE's 381[huh]R at about 0.5A per every 100uF with some
success. They are worth a look.

[huh] My brain froze there is a character in there

from digikey 381LX I think, wow you really drive those caps hard,

datasheet specs for part#: 381LX332M063H052

3300uF, 63V, 120Hz ripple 2.5Arms, 20kHz ripple 2.9Arms,
both at 105Celcius.

Do you think that cap could be operated with 15Arms ripple
at 200kHz, with ambient temperature below 50Celcius?

I guess it would be better to get two smaller ones so they
have more surface area for cooling, maybe two 1800uF ones:

part#: 381LX182M063H022
1800uF, 63V, 120Hz ripple 1.7Arms, 20kHz ripple 1.96Arms,
both at 105Celcius.

cheers,
Jamie
 
T

Tom Bruhns

Jan 1, 1970
0
Hi,

What is the best capacitor to use for this?

63V+ rated, 1250uF min capacitance, 15Arms 200kHz ripple rating

I was looking at electrolytic's, it would take 3 of these caps to get
15Arms ripple handling:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P749...

that would be 30000uF though! :)

Also that caps 5Arms ripple rating is at 10kHz, would this rating
increase or decrease for 200kHz typically for an electrolytic?

cheers,
Jamie

The way I'd normally think to handle something like this is to NOT use
an electrolytic directly, since they invariably have high enough ESR
that 15A RMS will cause significant heating. Rather I'd handle the
ripple with some very low ESR capacitance: ceramic or more likely
polypropylene in this particular case. WIMA make some very good
polyprops for applications like this. Use enough capacitance to get
the ripple voltage down to a reasonable value, and then you don't need
much inductance between that and bulk electrolytic capacitance to keep
the ripple current in the electrolytic at a more reasonable level.
Check out the WIMA MKP10 series. Panasonic ECWF and Vishay MKP379
series should also work well. Five 4.7uF 100V caps in parallel should
very easily handle the current and get the ripple down to a couple
volts p-p or less (depending on waveform). Even two or three would
handle the current easily, but might not get the ripple voltage low
enough--your design, your tradeoffs. Then even a fraction of a
microhenry off to bulk capacitance limits the ripple in the bulk to a
low value.

Cheers,
Tom
 
P

Phil Allison

Jan 1, 1970
0
"Jamie Morken = Smartarse **** "

** The operative word is " may " - you fucking, smartarse cunthead.

Long as an electro stays reasonably cool ( ie under 45C) it will last for
many years continuous service.

Why do you think so many SMPS using cheap ( ie no brand) electros have
fans in them - eh ??


GO DROP DEAD - MORKEN

YOU ARE ONE PATHETIC FUCKWIT


....... Phil
 
Q

qrk

Jan 1, 1970
0
Thanks Phil, also take a look at this:

**Use of temperature ripple current multipliers may limit life to the
hours specified for the maximum operating temperature.

which is 3000hours of operation (125days continuous use), is not enough
for this application.

cheers,
Jamie

For low esr capacitors, I like using United Chemi-Con KZE series. Digi
Key has this series. For 1250uF min capacitance, you need something
20% higher in value due to tolerance, or about 1600uF. 5 1000uF, 63V
KZE parts will get you to 15A ripple.

Are you making a many kW power supply? That's a lot of ripple current!
Ripple current is not the same as DC output current.

The lifetime of a Al electrolytic is ordinarily longer unless you're
operating the cap at maximum temperature.
The lifetime you can expect is:

L2 = L1 x 2^[(T1-T2)/10]

Where:
L1 = guaranteed life (hr) at temp T1 (deg C)
(spec sheet rating, e.g. 5000 hr @ 105 deg C)
L2 = expected life at temp T2 (deg C)
(your operating conditions)
T1 = spec sheet max temp
T2 = your operating temp (ambient plus self heating)

The KZE in your range is rated at 5000 hour @ 105 deg.
About 56k hours at 70 deg C.
About 113k hours at 60 deg C.
 
M

MooseFET

Jan 1, 1970
0
A whole bunch of NPO ceramics in parallel is the "best" if you aren't
worried about cost or space.
15A RMS at 200KHz is quite a lot of ripple to put through a single
capacitor.
I've used CDE's 381[huh]R at about 0.5A per every 100uF with some
success. They are worth a look.
[huh] My brain froze there is a character in there

from digikey 381LX I think, wow you really drive those caps hard,

www.cde.com/catalogs/381LR.pdf

381LR221M400A012 ESR=0.271@20KHz 2.03A@20KHz

It is a different part targeted as a "ultra high ripple capacitor"
datasheet specs for part#: 381LX332M063H052

3300uF, 63V, 120Hz ripple 2.5Arms, 20kHz ripple 2.9Arms,
both at 105Celcius.

Do you think that cap could be operated with 15Arms ripple
at 200kHz, with ambient temperature below 50Celcius?

No, they will heat themselves up too much. I don't like heat sinks on
capacitors.
 
J

Jamie Morken

Jan 1, 1970
0
qrk said:
For low esr capacitors, I like using United Chemi-Con KZE series. Digi
Key has this series. For 1250uF min capacitance, you need something
20% higher in value due to tolerance, or about 1600uF. 5 1000uF, 63V
KZE parts will get you to 15A ripple.

Thanks for the link, I will use 5 of those in parallel as you suggest,
they are pretty inexpensive too.

Also anyone have some good metal poly caps to use for a truesine (60Hz
120VAC output) LC filter cap? The current ripple is at 200kHz and is
max 15Amps peak to peak and about 7Arms. I need about 40uF for this
filter. I think the cap should be rated 400V for 120VAC.

MKP series from EPCOS, seem to be only for DC applications.
35uF/450V metal poly: $12 in 100's
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=495-3011-ND

FFV series from AVX
40uF/400VDC poly film: $25 in 100's
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=478-2616-ND

UNL series from Cornell Dibilier
30uF/400V poly film: $22 in 100's
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=338-1368-ND

Any other ones that could work and maybe cheaper? What about using
cheaper electrolytic's back to back to allow for bipolar voltages?

cheers,
Jamie





Are you making a many kW power supply? That's a lot of ripple current!
Ripple current is not the same as DC output current.

The lifetime of a Al electrolytic is ordinarily longer unless you're
operating the cap at maximum temperature.
The lifetime you can expect is:

L2 = L1 x 2^[(T1-T2)/10]

Where:
L1 = guaranteed life (hr) at temp T1 (deg C)
(spec sheet rating, e.g. 5000 hr @ 105 deg C)
L2 = expected life at temp T2 (deg C)
(your operating conditions)
T1 = spec sheet max temp
T2 = your operating temp (ambient plus self heating)

The KZE in your range is rated at 5000 hour @ 105 deg.
About 56k hours at 70 deg C.
About 113k hours at 60 deg C.
 
J

Jamie Morken

Jan 1, 1970
0
qrk said:
For low esr capacitors, I like using United Chemi-Con KZE series. Digi
Key has this series. For 1250uF min capacitance, you need something
20% higher in value due to tolerance, or about 1600uF. 5 1000uF, 63V
KZE parts will get you to 15A ripple.

Are you making a many kW power supply? That's a lot of ripple current!
Ripple current is not the same as DC output current.

Yes its a 3.6kW battery charger for charging 48V lead acid batteries :)

cheers,
Jamie

The lifetime of a Al electrolytic is ordinarily longer unless you're
operating the cap at maximum temperature.
The lifetime you can expect is:

L2 = L1 x 2^[(T1-T2)/10]

Where:
L1 = guaranteed life (hr) at temp T1 (deg C)
(spec sheet rating, e.g. 5000 hr @ 105 deg C)
L2 = expected life at temp T2 (deg C)
(your operating conditions)
T1 = spec sheet max temp
T2 = your operating temp (ambient plus self heating)

The KZE in your range is rated at 5000 hour @ 105 deg.
About 56k hours at 70 deg C.
About 113k hours at 60 deg C.
 
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