Author Topic: What is the ripple current rating of this film capacitor?  (Read 548 times)

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Online Faringdon

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What is the ripple current rating of this film capacitor?
« on: January 16, 2022, 04:45:37 pm »
Hi,
What is the ripple current rating of this film capacitor? (at 50/60 Hz and 20kHz)

MAB MKP 12/400 12UF +-5% 400V AC 30000h.....

https://www.ebay.com/itm/DVE-EN60252-MAB-MKP-12-400-12UF-5-400V-AC-30000h-Capacitor-New-Quantity-1-/372816438683

Here is its "datasheet"
https://www.rgbautomatyka.pl/media/docs/en/96/12UF%20MAB%20MKP%2012-400%20SIEMENS%20-%20product%20information.pdf
(it doesnt weigh 1Kg)

Attached also is datasheet...none tell the ripple current
 

Offline Gyro

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Re: What is the ripple current rating of this film capacitor?
« Reply #1 on: January 16, 2022, 07:00:20 pm »
Whatever the current they will pass at 50/60Hz AC (sine) at full rated voltage. They are intended for induction motor use and nothing more. If you push them harder, they will start to self-heal and lose capacitance.

Specifically, they are not rated for 20kHz.
« Last Edit: January 16, 2022, 07:04:27 pm by Gyro »
Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 
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Online Faringdon

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Re: What is the ripple current rating of this film capacitor?
« Reply #2 on: January 16, 2022, 07:58:30 pm »
So their current rating is VAC(rated)/Xc ?

Where
Xc = Xc at 50Hz and 12uF?


...that comes to 1.5A in this cap.

Also, Do you know anything about Film caps not having a ripple current rating, but just a dv/dt rating?
 

Offline Gyro

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Re: What is the ripple current rating of this film capacitor?
« Reply #3 on: January 16, 2022, 08:06:55 pm »
Try Epcos-TDK if you want fully rated high value, high dV/dt film caps. Be prepared to pay for them though! They're a lot more expensive than bog standard / ebay motor run types.
Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 
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Online Faringdon

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Re: What is the ripple current rating of this film capacitor?
« Reply #4 on: January 16, 2022, 09:50:16 pm »
Thanks, woudl you agree that the above cap is rated to 1.5A at 50Hz?
 

Offline Gyro

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Re: What is the ripple current rating of this film capacitor?
« Reply #5 on: January 16, 2022, 10:28:28 pm »
That seems a reasonable assumption.
Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 
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