Help with capacitor replacement please

[Martiv]

Hello ive registered for some advice.
My extractor for my workshop stopped and hummed
When I turn it off and on it worked...
Also when I tip it sideways it wont start but tilt it the right way again and it wil start.
So I opened it up and I found this.. I guess the capacitor is on its way out leaking like this.

I cant find a match online and I'm not sure about using different to exactly what it says on it that's out of my expertise..

Does this sound typical of the capacitor? I havent looked any further as this may be the issue.

The wires to motor will they still be ok? Cause there hardwired into the motor

Till its sorted I'll have to live with welding smells and fumes ?? neighbour complains of the flashing so i keep door shut ??

 

[telectrix]

how about this:

https://www.spares2you.co.uk/universal-capacitor-3uf-3mfd-4999907/

 

[freddo]

Available here.

Edit: crossed with Tel.

 

[pc1966]

Weight up postage as well. RS one (link by Freddo) is possibly better quality, but either should be OK.

 

[Martiv]

Thankyou.sovmuch. So dya think this is defo cause of my problems? Il take a look
Can i ask for knowledge ehy it says 450 475 500 v but the one showed in link only says 450...do i not need to match it alllll up? What info is used on that to match up?

 

[telectrix]

those voltages show parameters ( h/cl) , whatever that means,for each voltage. on a single phase supply, you can't have more than 230V (nominal) on the installation, so the ones we linked to should be fine.

 

[Lucien Nunes]

The voltages stated on a capacitor are maximum ratings. In this case multiple options are given, each with a typical service life. At 425V it should last 30,000 hours, at 475V the life is reduced to 10,000 hours. Note that the voltage on a motor run capacitor can exceed the supply voltage, so a 230V motor will be fitted with a capacitor rated well in excess of 230V. The higher the rating, the longer the life but the larger and more expensive the capacitor will usually be.

The capacitor is most likely the problem but if it is or was short-circuited, and the motor was powered up for some time with the capacitor in that condition and got very hot, the motor windings might be damaged. If the motor did not overheat, it's probably fine and a new cap will get it going.

 

[Timbo]

Let us not forget the peak voltage on 240Vrms is around 340V, or 320V on 230Vrms.

 

[pc1966]

Let us not forget the peak voltage on 240Vrms is around 340V, or 320V on 230Vrms.

Exactly. Typically a 400V DC-rated capacitor would be the absolute minimum for operation on an AC circuit of mains voltage, but you also have to factor in voltage spikes due to switching of motors, etc, and possibly the odd induced lightning surge.

As a result you will see capacitors intended for use on mains filters, etc, with special ratings as 'class X' for L-N operation and 'class Y' for L-E operation (where failing short circuit is a direct shock risk) which are capable of handling surges and generally designed to fail safe and not star a fire, etc.

 

[Lucien Nunes]

Capacitors supplied as motor start or run capacitors, and suppressors for connection across the line, always have their maximum AC voltage rating(s) shown as indicated by the little squiggle after the voltages on the original cap and the replacement in the link.

Film / foil and metallised film and paper capacitors with an AC rating (typically motor run caps) are usually capable of withstanding the corresponding peak voltage as DC. E.g. the 425V AC rating on the OP's cap implies that it's OK for 600V DC, although not specified for that purpose. Capacitors for general electronic applications typically have the rated DC voltage shown. A few have both AC and DC ratings.

AC-rated electrolytics (typically start caps) are constructed differently to their DC-rated counterparts and the two are not equivalent regardless of the voltage ratings. AC-rated types are a law unto themselves as they have all sorts of inherent limitations and are only used when other choices would be prohibitively large.

Then, with capacitors intended for direct connection across the AC mains, as PC1966 says you get the different safety categories. For motor run capacitors, there is a different protection mode classification. With the Ducati cap in the picture this is P0, which has no protection against failure in any particular way. P1 capacitors are allowed to fail open or short (but not in flames) and P2 are allowed to fail open-circuit only.

 

[Martiv]

It's not that bad.View attachment 56551

Available here.

Edit: crossed with Tel.

Weight up postage as well. RS one (link by Freddo) is possibly better quality, but either should be OK.

those voltages show parameters ( h/cl) , whatever that means,for each voltage. on a single phase supply, you can't have more than 230V (nominal) on the installation, so the ones we linked to should be fine.

Well rs online is 24hr delivery wow its here.

My problem is.. Mine has 2 terminals and this has 4 terminals?
The metal prongs the wired go onto. I only have 2 wired to hook up is that a problem?

 

[westward10]

Can you show a pic of the new capacitor terminals.

 

[Lucien Nunes]

Caps often have two terminals each with two connector tags with their flat faces parallel. You can sometimes see that each terminal is formed out of one U-shaped piece of metal.

 

[telectrix]

Caps often have two terminals each with two connector tags with their flat faces parallel. You can sometimes see that each terminal is formed out of one U-shaped piece of metal.

in that case, he can test with a multimter see which is short circuit to another.

 

[westward10]

You should be able to physically see it.

 

[Lucien Nunes]

Indeed you can. Connect to arrowed terminals. The others are just duplicates, ideally sleeve them with some insulating sleeving or heatshrink.

 

[Martiv]

Yeah here it is
How can i tell what wire to wich prong?
Totaly forgot to tske a pic of the wires.
Or are they both ok aslong as other is on oppasite side not joining prong?

If not... Forgive me how do I test with multimeter its a new tool to me i never had to use it lol
Got 2 wires out of the motor

Also thinking due to being 11 years old would it he beneficial to replace the wires also they arnt damaged but a bit not straight also.

And plugs only 1m i could add 2m and trade all the wire for 1.25 wire i have loads and 1.50

 

[westward10]

Connect as per #16.

 

[Martiv]

Connect as per #16.

Yeah.. So it doesnt matter in which way? Like i mean there is no plus and negative on the capacitoe no? Both terminals are the same just need to not be on the same u plug ye?

So i can plug n go.

 

[pc1966]

Most capacitors are non-polarised (at least the sort seen for motor use, etc) so just plug & go