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My kitchen hood vent is malfunctioning, the motor driving the fan is buzzing at different intensities depending on the speed I select. I took down the unit and if I give the fan blade a spin, it starts just fine and maintains it's speed.

I have figured out that the starter capacitor has run dry (we've had the unit for over 10 years, and it's rated for a max of 10000 hours at 420V)

Now I want to replace the cap, which has the following characteristics printed on it:

AV arcotronics 1 .27 .6CA2 MKP

3.15uF +- 5%

420V ~ 10000h/CLASS B

470V ~ 3000h/CLASS C

25/85/21

PO

CE 3.15 09340433

B X4

I've tried to find a capacitor rated for 470V/420V at 3.15 uF but I haven't had any luck. The only capacitors I can seem to find within my region (the Netherlands) have a rating of 450V, and either a capacitance of 3 uF, 5uF, 8uF or 10uF.

Since this capacitor is used to give the motor a bit of a boost at startup, I'm wondering if I can just swap in a higher value capacitor (I have a brand new 10 uF 450V capacitor lying around) without causing damage or it becoming a hazard.

Another thing is that the capacitors I manage to find all have 4 terminals instead of the two terminals that the capacitor that was built into the unit seems to have, any idea what that would be about?

The motor is being driven by mains AC (european mains)

To summarize my questions are:

  1. Can I replace the capacitor with one of a higher capacitance?
  2. What's with the 4 leads on the newer capacitors?

The built-in cap: upper_description under_description

The 4-lead capacitor:

4-terminal capacitor

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The answer is:

  1. NO, do not replace the 3.14uF with one of 10u.
  2. The four contacts are grouped 2 by 2, actually there are only two contacts, the free one can be used to add a parallel capacitor.
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  • \$\begingroup\$ Firt off, thanks for the answer :) point number 2 explains it well! About point 1: considering that as far as I can tell it's a capacitor for giving the motor some extra juice when starting, what would be an appropriate capacitance for a replacement considering the values I mentioned in my post: 3 uF, 5uF, 8uF or 10uF? \$\endgroup\$ – FMashiro Nov 19 '19 at 9:19
  • \$\begingroup\$ @FMashiro I would choose 3uF as it is the nearest value. \$\endgroup\$ – Marko Buršič Nov 19 '19 at 9:26
  • \$\begingroup\$ While I am not going to test whether the 10uF cap would have worked for long, I replaced the broken cap with the 3uF one and it works like a charm! Thanks again :) \$\endgroup\$ – FMashiro Nov 21 '19 at 8:42
  • \$\begingroup\$ (would be cool if you could expand on why exactly the 10u would be a terrible idea though) \$\endgroup\$ – FMashiro Nov 21 '19 at 8:42

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