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  1. #1
    Join Date
    Aug 2008
    Location
    Tennant Creek, Aust
    Age
    61
    Posts
    596

    Default Bench Grinder Capacitor

    The capacitor on my dad’s old bench grinder has given up the ghost.



    On the capacitor it says 110 volts, can I replace it with a capacitor that is 240 volts?




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    Ratty 05/2004 -05/07/2010 COOPER 01/08/1998-31/01/2012

  2. #2
    Join Date
    Sep 2008
    Location
    Narrabeen, Sydney NSW Australia
    Posts
    101

    Default

    Surprised it didn't go bang given that it's rated for ~50% of the actual line voltage, suppose it's a testimony to the quality of the original unit that it didn't, overbuilt with huge headroom and margin for safety - I would definitely be replacing it with the 240 volt equivalent.

  3. #3
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,439

    Default

    Hi Mark, Guys,

    With capacitors you can always use one of a higher voltage, never less. As far a capacitance is concerned, electrolytic capacitors have a quite wide tolerance value, usually as much as plus or minus 20%. So the actual value is not as critical as would be thought. AC rated capacitors can be connected either way round ! The only consideration is if it has a metal case that is connected to one of the terminals, in this case it has to be wired the right way round.
    Best Regards:
    Baron J.

  4. #4
    Join Date
    Aug 2008
    Location
    Tennant Creek, Aust
    Age
    61
    Posts
    596

    Default

    The yellow cap covers the terminals.

    The grinder is probably older than me, it was in dad’s shed as long as I can remember.
    What I don’t understand is that Australia is 240volt, why would they put a 110 volt capacitor in an Australian built machine?


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    Ratty 05/2004 -05/07/2010 COOPER 01/08/1998-31/01/2012

  5. #5
    Join Date
    Dec 2013
    Age
    56
    Posts
    1,416

    Default

    Agree, I've seen higher rated capacitors like 280, etc, used in 240v, but are usually 240 or 250v.
    There are some good online tutorials to help out if needed.

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    Using Tapatalk

  6. #6
    Join Date
    May 2018
    Location
    Brisbane
    Posts
    12

    Default bench grinder gap.

    Quote Originally Posted by BaronJ View Post
    Hi Mark, Guys,

    With capacitors you can always use one of a higher voltage, never less. As far a capacitance is concerned, electrolytic capacitors have a quite wide tolerance value, usually as much as plus or minus 20%. So the actual value is not as critical as would be thought. AC rated capacitors can be connected either way round ! The only consideration is if it has a metal case that is connected to one of the terminals, in this case it has to be wired the right way round.
    The capacitor is in series with the start winding not across the mails. The voltage is split between the start winding and the capacitor so it is less than the supply volts Maybe half or more or less depending. But a 240 volt one would be a good choice if it fits

  7. #7
    Join Date
    Feb 2013
    Location
    Laidley, SE Qld
    Posts
    1,038

    Default

    If the grinder is 60 plus years old it could have had more than one start capacitor swap. In a moment of need the 110V unit from a piece of surplus US electrics was tried, it worked, and was left in place.

    Buy a 240V or more 150mfd ± 20% cap with the correct terminals from your local electricial components supplier or online.

  8. #8
    Join Date
    Dec 2007
    Location
    Adelaide
    Posts
    574

    Default

    I've got the exact same 8inch grinder, purchased new in the early 1980's.

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