Hi Guys,

I want to estimate the life of the capacitor for below application.
I want to design AC to DC flyback converter and after bridge rectifier i am using this capacitor. -https://www.chemi-con.co.jp/en/products/detail-condenser.php?part_number=EKXG251ELL330MK20S

Max Voltage at capacitor is 180VDC (120Hz) for 120VACrms. My ambient temperature is 105C So i want to calculate the power dissipation and temperature rise of the capacitor ?

So i am asking below question to myself. If some one from this forum can help me.

1. How to calculate Power dissipation of Capacitor ?
2. How to calculate the temperature rise of Capacitor ?
3. How to estimate the capacitor life at ambient 105C ?
4. What happens if capacitor works at ambient 105C for longer duration ?

Thanks in Advance !

 

I would not expect an electrolytic capacitor operated at its temperature limit to last long.

This looks a better option with a 125⁰C limit, but they are not cheap, and I’d consider how to reduce the operating temperature if possible to maximise the capacitor life.

https://www.ebay.co.uk/itm/18465522...RFt9XOsqEX+PlM1O1Dl0/qFHyQ==|tkp:BFBMzMuO1r5i

 

Don't mount it under the hood of your Car, inside only.
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If you can tell us the RMS ripple current through the capacitor and the temperature rating of the capacitor and its specified lifetime at rating, we may be able to predict the life. The name of the manufacturer and the part number will probably also be very helpful.

 

If you can tell us the RMS ripple current through the capacitor and the temperature rating of the capacitor and its specified lifetime at rating, we may be able to predict the life. The name of the manufacturer and the part number will probably also be very helpful.

Hey...rms current you can see in capacitor data sheet which is .32A.

 

Hi...any other from group Admin.
Thanks

 

Hey...rms current you can see in capacitor data sheet which is .32A.

Are you running the capacitor at the 320mA ripple current is the question then. Ripple current is a major cause of the heating your after.

Electrolyticcapacitors have terrible performance over temperature, the manufacturer should be able to provide you with de ratting information.
In general, the better manufacturers supply more data, not least in that they test more.

 

Hey...rms current you can see in capacitor data sheet which is .32A.

The rated RMS current is helpful but you need to measure the actual RMS current in your application.