An odd capacitor...

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 It was pretty easy to identify what it was that went bang,
smelled funny, blew the power fuse for half the house and
made the sewing machine stop working. I cracked the sewing
maching open and found it full of electrolytic capacitor
guts!

 What's a little more difficult is identifying what it
is, and what to replace it with...

 Three electrolytic capacitors inside one can. Four poles
on the capacitor - two at each end (actually only two
connections. Physically, the can is a bit over an inch long,
and about 3/4 inch in diameter.

 Circuit looks like this: (fixed space font, Courier New or simlar)


 O----------------------------O
                   |
          ---------|
          |        |
    0.2u ===       |
GND-------|       === 0.1u
    0.2u ===       |
          |        |
          ---------|
                   |
 O----------------------------O

 Rating is 250VAC/350VDC. No apparent polarity.

 Brand is 'Jensen Capacitors'. They're a specialst mob that make
power caps for industrial and mains applications. Part number
*might* be something like 'J54U' or 'E-LUX 212407'.


 Does anyone know what this is called, or where I might get one
or something like it? It seems to be directly related to the
electric motor / starting type thing. Died of old age methinks.

 Thanks in advance,

GB
--
"When all you have is a flamethrower, everything looks like a
 speed camera." (Peter)

Re: An odd capacitor...



"GB"
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 **  But it aint an electro.


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**  Likely paper/ film/ foil types .

  (   Bet the 0.2 is really 0.02 uF.  )


Just go to DSE and buy one 0.1 uF  class "X2" caps and two 0.0047uF  class
"Y" caps.

Those caps suppress  RF  noise interference from the brushes arcing .




.........  Phil





Re: An odd capacitor...


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smaller capacitance than the original?
is this because of lower ESR?


Bye.
   Jasen

Re: An odd capacitor...



"Jasen Betts"
 Phil Allison
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**  Yes  -  there is a maximum value of suppression cap allowed to be
connected from A or N to earth inside appliances.


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**  Er  -  no.

It is because of   ELECTROCUTION   risk if a larger value is used.

If the earth pin is not connected at the AC outlet, then the frame of the
sewing machine becomes live because of the suppression caps.  The worst case
situation ( ie both line to ground filter caps fed from 240 AC to frame )
must not result in more than 1mA of AC current flow.

A pair of 0.0047uF caps meets that criterion PLUS the additional requirement
that they be class "Y"  approved types and hence have virtually  ZERO chance
of failing to a short in mains to ground service.

Class  "X"  caps do not have to meed such a stringent approval and may fail
short after a long period of use or severe spike voltage conditions.


BTW

I hope you are learning not to post dangerous guesses.



........   Phil




Re: An odd capacitor...


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 Thanks for the advice. I visited DSE today and purchased an 0.1uF
cap part no R2626, and a pair of 0.047uF X2 caps pn R2628 (and a bunch
of cheap Christmas lights that I Don't Really Need(tm)!).

 Having now *properly* read your advice, I shall go back there
tomorrow and buy the R2640 0.0047uF class Y capacitors!

 Thanks again,

G
--
"When all you have is a flamethrower, everything looks like a
 speed camera." (Peter)

Re: An odd capacitor...



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"Noise supressor" would be the generic term I think.  

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have you tried the agents for the sewing machine?

'E-LUX 212407'  could that be an Electrolux part number?

you could try them, 20 years ago the local Electrolux branch sold
me the equivalent part for my mom's vacuum cleaner.
(except box-shaped with polyester caps)

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AFAIK The only things connected to ground and to live conductors are noise
supressors.

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Most likely.

Bye.
   Jasen

Re: An odd capacitor...


remove the blown bits and plug it in

do you really need the cap(s)?


: It was pretty easy to identify what it was that went bang,
: smelled funny, blew the power fuse for half the house and
: made the sewing machine stop working. I cracked the sewing
: maching open and found it full of electrolytic capacitor
: guts!
:
: What's a little more difficult is identifying what it
: is, and what to replace it with...
:
: Three electrolytic capacitors inside one can. Four poles
: on the capacitor - two at each end (actually only two
: connections. Physically, the can is a bit over an inch long,
: and about 3/4 inch in diameter.
:
: Circuit looks like this: (fixed space font, Courier New or simlar)
:
:
: O----------------------------O
:                   |
:          ---------|
:          |        |
:    0.2u ===       |
: GND-------|       === 0.1u
:    0.2u ===       |
:          |        |
:          ---------|
:                   |
: O----------------------------O
:
: Rating is 250VAC/350VDC. No apparent polarity.
:
: Brand is 'Jensen Capacitors'. They're a specialst mob that make
: power caps for industrial and mains applications. Part number
: *might* be something like 'J54U' or 'E-LUX 212407'.
:
:
: Does anyone know what this is called, or where I might get one
: or something like it? It seems to be directly related to the
: electric motor / starting type thing. Died of old age methinks.
:
: Thanks in advance,
:
: GB
: --
: "When all you have is a flamethrower, everything looks like a
: speed camera." (Peter)


Re: An odd capacitor...


Tend to agree with Ed. Try it and see how the tv pays up.
The sewing machine repairer that I know usually takes them out as a
precaution.
I prefer to have them in myself. It may protect the brushes a bit.

John

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Re: An odd capacitor...


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Jensen still exist:
http://www.jensencapacitors.com /

You could ask or try as per Phil's suggestion.

Ken



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