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  1. #1
    Quote Originally Posted by paulus.v View Post
    You can go with the voltage higher and you will want to do that for better torque at high speeds.
    According to the rated torque you can go up to 32*sqrt(inductance)=43 volt.
    Or if you take the rated voltage you have a max. of 20*2.6V=52 volt.

    First calc. is more accurate but you have +/-20% inductance accuracy.
    Personally I would try with 45-46 volt, but I don't know how would the drives tolerate that voltage. Maybe there are others here with more experience in these drives.
    Have you tried wirh the drives set to the maximum amps rating? (SW1, SW2 and SW3 off)

    It is possible to be able to improve your speeds in other ways as well. How easy are your axes sliding on their guides? The quality of the belts and pulleys, the weight of the gantry, reducing the inertia of the rotational loads, etc
    Paul thanks for that advice, I got a 48 volt switching psu that can be turned down so will give it a go,

    Axis all run on hirwin rails, will add photo today for you to see,
    Thanks again you been big help. Kev

  2. #2
    The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.

    Hiwin rails need to be very carefully aligned to have a smooth movement.

    https://www.youtube.com/watch?v=AGT5gXpcmBA#t=1m58s

  3. #3
    Quote Originally Posted by paulus.v View Post
    The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.

    Hiwin rails need to be very carefully aligned to have a smooth movement.

    https://www.youtube.com/watch?v=AGT5gXpcmBA#t=1m58s
    that video is good info, learnt a lot about hirwi rails, best way line 1 side and slide car to each bolt both sides as you tighten rail up, moves super smooth then, as there is drag on them before fitting as they are preloaded, kev

  4. #4
    Quote Originally Posted by paulus.v View Post
    The 48V PSU will make a difference. Try with 4.5A but check the motors temperature, if they'll get too warm or hot, reduce the current. Higher current increases only the low speed torque.
    Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.

    Kev stick with your current supply for now. I suspect your problem comes from lack of pulses due to high micro stepping with low pulse rate.
    Setting lower micro stepping won't cause stalling and should allow higher tuning of velocity because less pulses are needed.
    3200 is too high and pointless really because most steppers can't resolve higher than this. What it does help with is smoothness but this comes at the cost of high number of pulses which can lower your velocity if can't provide them. If using parallel port with 25Khz then this will most likely be your problem.

    I've seen you mention 10mm but is that width or pitch.? T5 is 5mm pitch not 10mm. So with 20T your linear Pitch will be 100mm per rev.
    Now given your using 3200 pulses per rev and using frequency of 25Khz which is standard frequency for parallel port the max RPM you'll get from your motors is 468.75Rpm.
    This is calculated by taking frequency and dividing by pulses per rev or micro stepping in your case. This will then give Revs per Sec which you times by 60 to give RPM.
    Now take the pitch and times by RPM to get max velocity. So 100 x 468.75 = 46,875mm/min or 781.25 mm/sec .

    So you see if using 25khz with 3200 MS and 5mm pitch with 20T you can't possibly be reaching 800mm/sec.

    Drop the Micro stepping to 1600Ms and your RPM doubles and so does your Max velocity. Lowering Ms won't or shouldn't cause stalling motors. Unless your trying to spin them too fast.?
    By this I mean say if you used same parameters as above but with 400Ms then you could possibly tune the velocity so that the RPM is higher than the motors can handle so get saturated. Above 1500Rpm then steppers motors will struggle depending on load voltage etc.
    Last edited by JAZZCNC; 29-01-2017 at 10:29 PM.

  5. #5
    Quote Originally Posted by JAZZCNC View Post
    Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.
    I only advised 45V I said that I have no experience with these crappy drives. The Chinese say that the drives have over-voltage protection. I couldn't find any information about what chip is inside.

    My THB6064AH based drives, rated at 50V max, were happy at 46V with my 150kg gantry. At 48V they tripped an error (from back-EMF) with no damage.

    If they'll fry, he will be advised to get the AM882 and see how nice his machine will move at 100mtr/min.

    I was impressed by these DSP drives. They more than doubled the speed, with the same voltage and current setting.

    Quote Originally Posted by JAZZCNC View Post
    If using parallel port with 25Khz then this will most likely be your problem.
    He is using an AWC-608 Controller. I couldn't find any information about the step output frequency. Found somewhere "150MH". Could it be they spelled wrong 150kHz?

    Quote Originally Posted by kev20009 View Post
    Now I can only set steps to 3200 any lower stalls and can only move at about 4mm second
    What should I understand from the above sentence? What means 'lower' and 'only'?

    I googled these drives and found them popular on 3D printers not a 50mtr/min laser...

  6. #6
    Quote Originally Posted by JAZZCNC View Post
    Yes it will make a difference it will blow the bloody drives up.!!! . . . . Why do you people give advise without looking and knowing exactly what your telling people to do.? These drives are 50V Max and 48vdc is far too close to limit and when traveling at high feeds the back EMF will fry the drives.

    Kev stick with your current supply for now. I suspect your problem comes from lack of pulses due to high micro stepping with low pulse rate.
    Setting lower micro stepping won't cause stalling and should allow higher tuning of velocity because less pulses are needed.
    3200 is too high and pointless really because most steppers can't resolve higher than this. What it does help with is smoothness but this comes at the cost of high number of pulses which can lower your velocity if can't provide them. If using parallel port with 25Khz then this will most likely be your problem.

    I've seen you mention 10mm but is that width or pitch.? T5 is 5mm pitch not 10mm. So with 20T your linear Pitch will be 100mm per rev.
    Now given your using 3200 pulses per rev and using frequency of 25Khz which is standard frequency for parallel port the max RPM you'll get from your motors is 468.75Rpm.
    This is calculated by taking frequency and dividing by pulses per rev or micro stepping in your case. This will then give Revs per Sec which you times by 60 to give RPM.
    Now take the pitch and times by RPM to get max velocity. So 100 x 468.75 = 46,875mm/min or 781.25 mm/sec .

    So you see if using 25khz with 3200 MS and 5mm pitch with 20T you can't possibly be reaching 800mm/sec.

    Drop the Micro stepping to 1600Ms and your RPM doubles and so does your Max velocity. Lowering Ms won't or shouldn't cause stalling motors. Unless your trying to spin them too fast.?
    By this I mean say if you used same parameters as above but with 400Ms then you could possibly tune the velocity so that the RPM is higher than the motors can handle so get saturated. Above 1500Rpm then steppers motors will struggle depending on load voltage etc.
    Hi jazz, The belts are 10mm wide t5 20 tooth pulley,
    This is a laser cutter running awc608 laser controler,

    The steps it's set to now I can move back and forth nice, but if set them lower they just move 3mm and stall, so not sure if this is through psu needing bit more power, or turning amps up,

    The 48volt psu I got as a ajust screw, if this is turned down to lower volt would it hurt the psu or are they ok,

    Thanks jazz kev

  7. #7
    Quote Originally Posted by kev20009 View Post
    Hi jazz, The belts are 10mm wide t5 20 tooth pulley,
    This is a laser cutter running awc608 laser controler,

    The steps it's set to now I can move back and forth nice, but if set them lower they just move 3mm and stall, so not sure if this is through psu needing bit more power, or turning amps up,

    The 48volt psu I got as a ajust screw, if this is turned down to lower volt would it hurt the psu or are they ok,

    Thanks jazz kev
    Ok I see on the controller front and while I can't find the Frequency this controller works at I'm sure it will be more than 25Khz so lack of pulses shouldn't be problem. Still However lowering the MS shouldn't cause stalling motors provided you set it up corrrectly in the controller which might be your issue if not doing this.

    The motors you are using are relatively high Inductance so will require more voltage to spin fast but still with 100mm pitch they should easily reach 500rpm if wired Bi-polar parallel.
    If series wired then this could be your issue because torque drops away quickly as RPM increases and with only 36V may struggle to spin much more than 500rpm.

    Do the Motors have 4 wires or 8 wires.?

  8. #8
    Quote Originally Posted by JAZZCNC View Post
    Ok I see on the controller front and while I can't find the Frequency this controller works at I'm sure it will be more than 25Khz so lack of pulses shouldn't be problem. Still However lowering the MS shouldn't cause stalling motors provided you set it up corrrectly in the controller which might be your issue if not doing this.

    The motors you are using are relatively high Inductance so will require more voltage to spin fast but still with 100mm pitch they should easily reach 500rpm if wired Bi-polar parallel.
    If series wired then this could be your issue because torque drops away quickly as RPM increases and with only 36V may struggle to spin much more than 500rpm.

    Do the Motors have 4 wires or 8 wires.?
    hi jazz 8 wires wired parallel, the only settings that can be set in controller is calibrate the distance moved, table size, homing switches
    I cut square 100mmx100mm and put that in till it gets to right um pulse, which works out at x 15.621760 and y 15.575712

    thanks jazz kev

  9. #9
    Quote Originally Posted by JAZZCNC View Post
    The motors you are using are relatively high Inductance so will require more voltage to spin fast
    Hi Dean,

    It would not be advisable to get the am882 drives and a decent toroidal psu (I guess around 60v, you have more experience..)?

    I see that he had invested a lot in his build but got stuck with some crap drives, and he only needs two of them.

    edit:
    Quote Originally Posted by kev20009 View Post
    the only settings that can be set in controller is calibrate the distance moved, table size, homing switches
    Kev, I told you about the importance of setting up acceleration. Did you get the idea?

    From your controller manual:

    【Max Acc.】: Acceleration when axis making accelerated or decelerated movement. Too a big setting may lead
    to motor losing steps or dither; too small setting may cause slow acceleration and then slow
    processing speed for whole image. For axis with big resistance, such as Y axes corresponding
    with beams, typical setting should be within in 800~3000mm/s2 ; For axis with small resistance,
    such as X axes corresponding with carts, typical setting should be within in 10000~
    20000mm/s2;
    Last edited by paulus.v; 30-01-2017 at 11:38 PM.

  10. #10
    Quote Originally Posted by paulus.v View Post
    Hi Dean,

    It would not be advisable to get the am882 drives and a decent toroidal psu (I guess around 60v, you have more experience..)?

    I see that he had invested a lot in his build but got stuck with some crap drives, and he only needs two of them.
    With 100mm pitch then shouldn't need it. 500Rpm isn't diffcult to reach provided theres enough pulses.

    Now what I'm not understanding is the numbers given.? 15.62 for 100mm of movement would suggest close to 205mm pitch with 3200 MS.
    So to me there must be ratio going on somewhere.? . . . or the Belts are not T5.?

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