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Thread: Capacitor

  1. #1
    Senior Member Lukemc's Avatar
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    Capacitor

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hey all. I'm roasting with a north coffee 1kg roaster at present.

    The cooling "stirrer" takes ages to start up and get to speed on first use. Once at speed you can turn it on and off and it operates normally. Until the next roast session when it's back to slow.

    Does anyone think that this capacitor (wired between the plug and motor) is the cause? Worth replacing?

    If so any clues as to where I'd find a replacement? Jaycar maybe?

    Any advice welcome

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  2. #2
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    I'd guess that is a motor start/run capacitor - so yep change it out. I don't know if Jaycar would have it, more likely you could get something from RS Components. Or the first thing I did was Google that for you
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  3. #3
    Senior Member Lukemc's Avatar
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    Thanks Caps appreciate the link too. Not sure why I didn't hit google tbh

  4. #4
    Senior Member gonzob's Avatar
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    I think it's unlikely that the capacitor will "fix" itself, and after a while operate normally. It is probably more likely to be sticky motor bearings which often free-up with use. I take it that the stirrer motor is a small one (15watt, going through a gearbox??) - the bearings may be plain bronze bushings, and may only need some oiling.

    Gonzo
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  5. #5
    Senior Member readeral's Avatar
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    My bet is still on it being the capacitor.

  6. #6
    Senior Member Lukemc's Avatar
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    Thanks gonzo and readeral. Will report back next week and let you guys know the result.

  7. #7
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    The capacitor is a possible cause but I'm with gonzob and going for the bearings on this one :-)

    Cheers,

    Matt

  8. #8
    Senior Member Lukemc's Avatar
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    For interest sakes here's the motor!!



    I'll see if I can get to the bearing and oil it tonight. Thanks again
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  9. #9
    Mal Dimal's Avatar
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    Ladies and Gentlemen, place your bets...

    Mal.
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  10. #10
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    Hold on, I just answered the OP's question about the capacitor. If there is money on it, and there are bearings and gears, that's what i would back can you turn it manually? You should be able to feel the bearings grinding, or some resistance.

    But it is a single phase motor, so it could be just a 'start' capacitor which should alter the current to the windings of the motor to create a rotating magnetic field. Could this explain why when it is switched on and off once it gets up to speed it is OK, but into the next roast the magnetic field has dissipated? Anyway for the sake of a $5-$6 I still would replace the capacitor.

  11. #11
    Senior Member Lukemc's Avatar
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    I assumed I would undo the 4 Allen head screws, seperate the back and front and find the bush/bearing.
    Not so!!

    This is what I found. It's covered in a heavy clear grease too. So I put it back together and will await further advice!


  12. #12
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    Can you start the motor with it removed? With the motor out does the stirrer turn freely?
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  13. #13
    Mal Dimal's Avatar
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    Quote Originally Posted by Lukemc View Post
    It's covered in a heavy clear grease too. So I put it back together and will await further advice!
    Looks like a Shell Lithium type of grease commonly used with electric motor bearings/gearboxes, etc...

    Mal.

  14. #14
    Senior Member Lukemc's Avatar
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    Quote Originally Posted by Caps View Post
    Can you start the motor with it removed? With the motor out does the stirrer turn freely?
    DOH

    Didn't try either!! I'm a bit sleep deprived at present! I just put it back together.......

    Will attempt both tomorrow.
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  15. #15
    Senior Member Lukemc's Avatar
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    Finally got a minute to myself and changed the capacitor tonight. No change unfortunately. Does this mean I need to replace the motor or is there a way to get it apart and grease inside it?

  16. #16
    Senior Member Lukemc's Avatar
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    Capacitor

    So the motor part at the back that come off sounds freely. It's the gearbox that's really hard to turn (picture below). I'm not sure how to remove it and since it frees up after 30 seconds or so I've put it back for the time being. I need to roast tonight!!!!


  17. #17
    Senior Member gonzob's Avatar
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    I found a reference document for the gearbox:

    http://site.motadistribution.com/Bro...earTechRef.pdf

    It's not too accurate, but it looks like the gearbox cover is removed on the OUTPUT shaft side, so you'll have to take it off the stirrer assembly before pulling it apart.

    By the way, how do you know the gearbox is stiff? Trying to turn the output shaft on a reduction box doesn't give a good indication of whether it turns freely (the mechanical advantage is working against you), and you can't turn the input shaft, because it comes off with the motor....

    Gonzo.
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  18. #18
    Senior Member Lukemc's Avatar
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    Behmor Coffee Roaster
    Good point Gonzo. I assumed stuff as the input shaft turned freely.

    I'll have to disassemble the whole thing.

    Can the grease they used be too thick and that's why it takes time to free up do you think? It's almost glue like......



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