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IndustryArena Forum > CNC Electronics > Servo Motors / Drives > Wondering About Huge Differences in Cost Between Drives of Same Power
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  1. #1
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    Wondering About Huge Differences in Cost Between Drives of Same Power

    Hi
    I have a 140V 14 A rated brushed DC servo motor and I am looking for a convenient drive.
    I found some drives that match my motor but I was shoked by the huge differences in prices and also in sizes of the drives although they have similar output powers. For example the suitable xenus drive for my motor from copley controls is nearly 1600 $ while the suitable drive from granite devices is 299 $.
    It would be a great reduction in cost for me to buy the granite devices drive but I got so suspicious because of the huge difference between it and the one from copley.
    So could anyone explain the reason for this difference in prices and does the small size from granite devices mean smaller power semiconductors ?

    waleed alhadidi

  2. #2
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    Waleed, I can't explain the difference in price, but I have used the Granite drives and been very happy with them.

    With your brushed DC motors, I believe they can be run at their full capacity (160V/14A cont/40A peak). My BLDC motors are only using a fraction of that at 72V and perhaps 5A continuous.

    You might want to ask in the Granite Drive area and see if anyone is pushing them to their limits.

    Steve

  3. #3
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    Thank you Steve,
    I believe it can do the job but I'm still wondering will it do the job with the same efficiency as the more expensive alternatives. Sorry but the difference in cost is too much that makes you suspicious but I really need to buy the cheapest that will do the job.

    Waleed

  4. #4
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    The Xenus drives seem to be capable of 4KW output while the Granite are more like 1.5KW. So the power handling advantage is with the Copley drives. I don't know about the feature sets. The Granite seem to be quite feature rich with a good software tool for configuration and tuning. Maybe one of the experts will jump in here and add some thoughts.

    Steve

  5. #5
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    Yes it's kind of clear now also because the xenus works on AC supply voltage that means it has an AC to DC converter inside in addition to some options like the can open which makes it larger and more expensive.
    Thanks for the help Steve.

    Waleed.

  6. #6
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    I use VSDEX 160 dual DC to drive 2 ea DC motor. I use it on my cnc plasma 2.20 m X 1.20 m. So only 2 ea VSDEX 160 dual DC for 4 ea DC servo motor. Wiring is easy, I use 2 ea 50 mm ballscrew on X (long axis). It works OK.

  7. #7
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    Thank you asuratman. So what is your motors' voltage and current consumption. And for how long the drives have been working with you ?

    Waleed.

  8. #8
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    My motor 90 VDC 10 Amp, all 4. I use 2 ea 1500 watt power supply, each drive use 1 ea unregulated power supply (I have them lying around for long time). I use my drive on my cnc plasma (actually oxy cutting torch) for 2 months. Then I work on to retrofit my CNC lathe Ikegai FX25N and I build another cnc lathe in progress. So actually I need 2 more driver. Its kind of experimental, I plan to buy another 2 each. I have no problem with my driver, but I wait to buy plasma.

  9. #9
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    My cnc plasma

    Here is my cnc plasma table. I have disassembled my GD control and some parts. Its rusty, but only thin. The rust can be removed using wire brush, then prime and paint. Here is very humid.
    Attached Files Attached Files

  10. #10
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    Wow that is so rusty, but seems rigid
    Hope you finish it soon pal
    Thanks for help

    Waleed

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