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  1. #11
    Quote Originally Posted by Clive S View Post
    Ok if you are happy BUT can you home them individually to square the gantry!!!
    Asked pmdx direct And got Instant replies as I wasn't 100% on slaving and squaring
    Click image for larger version. 

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  2. #12
    Quote Originally Posted by Lewywri89 View Post
    So 60v - 62v would be the correct size psu? If I use 68v I assume I would have unwanted motor heat?
    is anyone in the north west able to make a psu for me for a fee
    cant find enough info to buy the parts and build myself
    would like a linear psu to minimize electrical noise
    Also what amp psu would be sufficient
    thanks again
    lewis
    It is not that hard to build your PSU. you only need a toroidal transformer, a bridge rectifier, a capacitor and fuse(s) if you want to be on the safer side.

    I would go with a 45V 500VA toroid (or 625VA max.) but here you may find different answers as there is not a generally accepted formula to calculate the power you need.

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  4. #13
    Quote Originally Posted by paulus.v View Post
    It is not that hard to build your PSU. you only need a toroidal transformer, a bridge rectifier, a capacitor and fuse(s) if you want to be on the safer side.

    I would go with a 45V 500VA toroid (or 625VA max.) but here you may find different answers as there is not a generally accepted formula to calculate the power you need.
    I think you have it spot on and they can all be purchased here http://www.rapidonline.com/electronic-components
    ..Clive
    The more you know, The better you know, How little you know

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  6. #14
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 3 Hours Ago Has been a member for 9-10 years. Has a total post count of 1,833. Received thanks 192 times, giving thanks to others 5 times.
    I'd probably err on the side of caution and go for a 40V toroid.

    Theoretically, 40VAC should give 57VDC, and 45VAC give 63.6VDC, however that's assuming perfect mains voltage of 230VAC, however it will more than likely will be higher.
    Allowing 10% gives a reasonably safety margin.

    Typical current guidelines IIRC are 50% of the total of maximum motor current for all motors (that gecko guide I linked to previously covers it), however it's always good to go slightly bigger, and from what I remember there's not much price difference between a 500VA and 625VA toroid.

    Rapid Online should have everything you'd need. I normally use RS, but I've got an account with them so I get free postage. Airlink Transformers can be cheaper for the transformers.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

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  8. #15
    Thank you
    If I go for the 45v 625va from rapid online (new shop to me so thanks)
    could anyone tell me the values of the other components needed

  9. #16
    The bridge rectifier values should be higher than your output. 50A 600V is a common value, for example. You need aluminium electrolytic capacitor. One or more wired in parallel to the DC output of the rectifier. The voltage should exceed your output values, 80V or the more common 100V. Regarding the capacitance, the larger the better, but they are not cheap. I recommend at least 20.000 uF. You may find these large capacitors also with screw terminals that are easier to wire, without the need of soldering. On the toroid mains input I would put a simple glass fuse, T4A (time delay fuse). Not sure about the output fuse, probably a circuit breaker will be more robust. Personally I have only the fuse on the mains.

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  11. #17
    Don't worry about running higher than 32x Inductance rule because the motors won't be damaged or wear out from heat. You'll find they will happily run at 70Vdc without any issues from heat. The extra voltage is welcome because it gives more speed and to lesser degree torque.

    All machines I build get fitted with 2 x 25V 500 or 625Va depending on number of motors. 625Va for 4 motors with Seconderys wired in series. This gives approx 68Vdc output. Don't go higher than 625Va else you'll suffer with In-rush current tripping fuses etc.

    Regards Capacitors then you don't need one large Cap. You can use several wired in parallel. Infact your better doing this because it lowers ripple and is much cheaper.
    3 or 4 x 4700uf 100v is what I use.

    This is what I fit given your motors etc.

    Toroid = 625Va 2 x 25V
    Caps = 4 x 4700uf 100V
    Bridge = 35A 300v or higher.

    The wiring is simple as it gets. See pic to give an idea of how simple.

    Click image for larger version. 

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  12. #18
    Should I buy the one from zapp automation for simplicity
    68v 6amp linear psu
    is 6amp enough for my system?

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