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Need replacement capacitor but value not readable

Zapper

Sep 28, 2015
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Sep 28, 2015
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Hi,
I have a Eurotherm 91e Temp Controller that has blown a capacitor. I know it's a RIFA PME 2371Y 40/100/56C but the value has blown off.

I can't justify taking it to Eurotherm as they charge a lot from memory. I can't find a schematic or photo of the circuit board. I posted already on the Eurotherm Forum but had no reply.

Is there a practical way to work out the capacitance from the circuit board
 

Zapper

Sep 28, 2015
7
Joined
Sep 28, 2015
Messages
7
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I used these .0047uf RIFA PME 2371Y 40/100/56B on other Eurotherm models but I've never paid attention to what was in the 91e
 

davenn

Moderator
Sep 5, 2009
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Sep 5, 2009
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14,240
thanks for the pix

OK I would backtrack on my previous 40uF they would be so much bigger than what is present

it appears to be a polypropylene / metalised ... polyprop for short

I would suggest that in your first pic the PME 271 Y may be the value with the line below stating the tolerance and voltage rating etc

but then 271 = 270pF would appear to be way too small a value for a PSU



some one else may do a better interpretation


Dave
 

dave9

Mar 5, 2017
1,188
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Mar 5, 2017
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1,188
It's a (now Kemet, originally Rifa) class Y2, 250VAC, metalized paper, EMI suppression cap.

The 40/100/56/C is just an IEC Climatic Category rating.

There is no way to determine the capacitance value based on the markings remaining.

They're available in capacitance range of 0.001 - 0.1 uF and lead spacing of 10.2, 15.2, 20.3, 22.5, 25.4. They may have dropped the 22.5 size at some point.

If you look on the following datasheet you can narrow the range of possible capacitance based on the lead spacing, on page 5.
If you measure the dimensions in width "B", height "H", and length "L" you might narrow the possible capacitance even further. I know, this will be hard to do with it swollen like a balloon so make your best guess.

The same chart also shows new Kemet part #s though you wouldn't "need" to get this exact cap, another class Y2 250VAC (or higher) film cap that fits would work.

https://content.kemet.com/datasheets/KEM_F3016_PME271Y_Y2_250.pdf
 
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