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  1. #1
    I'm running 3 Leadshine AM822 drivers with 2 at more or less their maximum current (5.86A RMS) and my 36v switch-mode power supply just isn't up to it.

    I've been recommended to buy an unregulated supply of around 60-70v. I'm guessing that a 10A supply will be enough to drive all three motors (the Z axis requires very little power). Can anyone recommend a supplier or a method of construction.

    While I currently have just 3 axes but might want to increase to 5 although the 4th and 5th will need lower power motors.

  2. #2
    Clive S's Avatar
    Lives in Marple Stockport, United Kingdom. Last Activity: 12 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 3,333. Received thanks 618 times, giving thanks to others 78 times. Made a monetary donation to the upkeep of the community. Is a beta tester for Machinists Network features.
    Quote Originally Posted by Agathon View Post
    I'm running 3 Leadshine AM822 drivers with 2 at more or less their maximum current (5.86A RMS) and my 36v switch-mode power supply just isn't up to it.

    I've been recommended to buy an unregulated supply of around 60-70v. I'm guessing that a 10A supply will be enough to drive all three motors (the Z axis requires very little power). Can anyone recommend a supplier or a method of construction.

    While I currently have just 3 axes but might want to increase to 5 although the 4th and 5th will need lower power motors.
    Ok I am in Spain after a bit of vino But here is a link http://www.zappautomation.co.uk/ps80...er-supply.html but you could build your own for nearly half the price with bits from Rapid on line. https://www.rapidonline.com/electronic-components
    ..Clive
    The more you know, The better you know, How little you know

  3. #3
    Thanks Clive - I bet it's hot there!

    I've seen those rectifier/smoothing capacitor boards on most home-built PSUs are they available from eBay and Aliexpress? Not quite sure what to search for.

    Enjoy you holiday!

    David

  4. #4
    Having thought about it, I only need to run 2 of the AM822s from a 60-72v PSU. If they are set at their maximum current what sort of VA do I need from the transformer? I'm guessing this will partly depend on the specification of the smoothing capacitors.

  5. #5
    Clive S's Avatar
    Lives in Marple Stockport, United Kingdom. Last Activity: 12 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 3,333. Received thanks 618 times, giving thanks to others 78 times. Made a monetary donation to the upkeep of the community. Is a beta tester for Machinists Network features.
    Quote Originally Posted by Agathon View Post
    Having thought about it, I only need to run 2 of the AM822s from a 60-72v PSU. If they are set at their maximum current what sort of VA do I need from the transformer? I'm guessing this will partly depend on the specification of the smoothing capacitors.
    Some links here.
    https://www.rapidonline.com/50a-brid...al-case-519318

    https://www.rapidonline.com/samwha-h...acitor-11-3121

    https://www.rapidonline.com/lcr-ep08...-clamp-11-3004

    This has secondary of 25-25v some people like 24 - 24V
    https://www.rapidonline.com/vigortro...-x-25v-88-0005

    And a vid by Joe. He used 4 caps but three is fine.
    https://www.youtube.com/watch?v=4OoQQg76ar4
    https://www.youtube.com/watch?v=WISDqx-e23M
    ..Clive
    The more you know, The better you know, How little you know

  6. #6
    Many thanks.

    What do you think about power output. I'm running the 2 AM822s at 5.8A RMS (actually, I think that once I have the interface cable I'll programme the drives to 5.5A RMS (2.8 x 1.96) - but that's splitting hairs) so that's total RMS current of 11.6A. The AM822 manual says that 50-70% of the motor current will be sufficient.

    So 2 x 5.5A = 11.0A. 50-70% = 5.5-7.7A x 70v = 385-539VA. So a 500VA transformer should be OK?

    Does that sound right or should I be working with the AC output voltage of 50v?

    I see that Joe used a massive 750VA transformer.

  7. #7
    Clive S's Avatar
    Lives in Marple Stockport, United Kingdom. Last Activity: 12 Hours Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 3,333. Received thanks 618 times, giving thanks to others 78 times. Made a monetary donation to the upkeep of the community. Is a beta tester for Machinists Network features.
    Quote Originally Posted by Agathon View Post
    Thanks Clive - I bet it's hot there!

    I've seen those rectifier/smoothing capacitor boards on most home-built PSUs are they available from eBay and Aliexpress? Not quite sure what to search for.

    Enjoy you holiday!

    David
    The boards I think you are referring to are not suitable as they have very small caps on them.
    ..Clive
    The more you know, The better you know, How little you know

  8. #8
    Have a look at Joe's recent build:
    http://www.mycncuk.com/threads/4513-...-router/page19
    post #373 onwards

    And mine from a while ago:
    http://www.mycncuk.com/threads/6988-routercnc_MK3/page3
    Building a CNC machine to make a better one since 2010 . . .
    MK1 (1st photo), MK2, MK3, MK4

  9. Thanks John, I have the din mounted flip down type fuse holder so not sure without looking at it if this would be possible but I understand the principal and I'm sure there would be a way!


    Sent from my iPhone using Tapatalk

  10. #10
    Quote Originally Posted by JoeHarris View Post
    Thanks John, I have the din mounted flip down type fuse holder so not sure without looking at it if this would be possible but I understand the principal and I'm sure there would be a way!


    Sent from my iPhone using Tapatalk
    That sounds like you're talking about the AC PSU input fuse. You definitely don't want any diodes in that position!

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