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  1. #1
    Member
    Join Date
    Nov 2015
    Posts
    8

    Stepper Amperage

    I am retrofitting a mill and the old steppers just aren't working well on all three axis so I am replacing them and the drivers as well. I am planning on keeping the power supply, but I want to make sure I don't get to high Amperage steppers.

    The power supply is a 48volt toroidal power supply. It has wires running to each stepper and each of those three circuits has a 2 Amp Fuse on it. Does that mean I can use the 2/3 rule and use 3 Amps steppers? Or am I limited to 2 Amp steppers, because of the fuses?

  2. #2
    Member
    Join Date
    Jul 2018
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    2042

    Re: Stepper Amperage

    If you get "higher" amperage steppers they will work, just at the set amperage of the driver. Maybe the steppers are fine and you need to adjust the driver settings or the controller settings (or its a mechanical issue with the machine. tight bearings, alignment etc). I'd work through the system before replacing anything and track down the exact cause of the issue. What do you mean by "not working well" steppers either work or don't work? usually.. Peter

  3. #3
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
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    35176

    Re: Stepper Amperage

    What's the current rating on the power supply?
    I'd get rid of the fuses, and get 5 or 6 amp steppers. Typically, the higher the current, the better the performance. 2-3 amp steppers are on the lower end for power and speed.
    Gerry

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  4. #4
    Junior Member
    Join Date
    May 2006
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    3547

    Re: Stepper Amperage

    Note that the average current from a supply is usually much lower than the stepper current. For example a 2.4V 5A motor will only draw about 0.25A from a 48V supply when stopped due to conservation of energy. Both are 12Watts. As the motor moves under load the motor will provide mechanical power and draw more current from the supply.
    TK
    http://dynomotion.com

  5. #5
    Member
    Join Date
    Nov 2015
    Posts
    8

    Re: Stepper Amperage

    Its definitely the steppers that are bad. When I test it the X axis works fine. The Z axis didn't move at all I removed the stepper and it was spinning only intermittently when I test it. The Y axis works fine going down but going up it skips and makes noise. All three of the drivers seem to be working though since I tested them on the X axis.

    The transformer is made by Talema its about 110mm x 60mm I cant find the model number on their site and it doesn't have any specification other then that on the side. It might be similar to one of these.

    https://talema.com/wp-content/upload...ary-0225VA.pdf

    https://talema.com/wp-content/upload...ary-0300VA.pdf

    Click image for larger version. 

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    The mill is a LabVolt 5600. The capacitor is a mallory.

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