. .
  1. #1
    hi i have a denford cyclone lathe it has 2 x 8nm nema 34 steppers on it 2:1 reduction 5mm pitch lead screw .
    i wish to change them out for 2x ac servo motors.

    can anyone recommend someone who sells them, and also what size would be ideal. 750w/1kw

    ive seen these on eBay around 300 1kw 4nm
    and
    90ST-M02430 Matched Servo Driver 2.4N.M 750w servo motor

    im new to servos ,but im after something with an encoder for accuracy and be compatible with my centroid cnc12 lathe control i just fitted

    any help appreciated

  2. #2
    Doddy's Avatar
    Lives in Preston, United Kingdom. Last Activity: 2 Hours Ago Has been a member for 7-8 years. Has a total post count of 1,252. Received thanks 172 times, giving thanks to others 57 times. Referred 1 members to the community.
    Theres a Czech-based supplier on eBay that I bought a 2kW servo (lathe) from - no drama and quick delivery, but the Chinese ebay vendors (750w - mill) are equally competent, just slower shipping, though very good at responding to queries (in my case a PDF of the manual prior to delivery). I run both in step/dir positional mode like a stepper, but both as spindles (one on a ML7 lathe and use the encoder for position feedback)
    Last edited by Doddy; 25-02-2021 at 07:19 AM.

  3. #3
    Not 100% sure but I seem to recall the Denford Cyclone to be a small lathe. If that is correct then I think 1Kw motors will likely be overkill, I would think 400W may be more suited.

  4. #4
    its not that big but they did come with up to a 5hp motor depending on original option taken.around 150 x z around 200

    things are a lot better now i have centroid and an encoder on the spindle compared to mach3 before . But i think servos would be a better option and give a bit of a comfort blanket for accuracy if I'm not mistaken .
    So if 750w looks more than enough from peoples experience that's fine i know what ball park to be in .
    if anyone has links from any vendor they have used and trust that would be great

    cheers

  5. #5
    m_c's Avatar
    Lives in East Lothian, 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 2,608. Received thanks 316 times, giving thanks to others 8 times.
    I put a 400W on the X-axis, and a 750W on the Z-axis of my Cyclone, although I think I changed the gearing on mine to give a greater ratio so the servos could run faster.

    If I was doing one again, I'd probably just use two 400W servos with suitable gearing.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  6. #6
    thanks
    is there any disadvantage to 750w or 1kw on both, as for gearing was it 1:1

    please correct me if im wrong but im under the illusion that with the servos and driver kit if it "loses steps" ie out of position it will alarm or something to stop inaccurate turning

  7. #7
    m_c's Avatar
    Lives in East Lothian, 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 2,608. Received thanks 316 times, giving thanks to others 8 times.
    Quote Originally Posted by iamspuddy View Post
    thanks
    is there any disadvantage to 750w or 1kw on both, as for gearing was it 1:1
    How much breaks if something goes wrong :-)
    Although too big a servo on too light an axis can cause tuning/stability problems.

    IIRC the amount of space available to put a bigger motor on the X-axis is limited, so it's something you have to consider.

    I think I went to somewhere around 2:1 ratio, possibly a bit higher.
    Steppers aren't fast, and it's unlikely you'd ever run one above 1000rpm (500rpm is probably more feasible for reliable operation), whereas most servos around a similar size will quite happily spin at 3000rpm.
    If you direct couple a servo at 5mm pitch, at full speed you'll theoretically get 15m/min, but you're never likely to reach that speed due to the axes being so short, there simply won't be enough distance to accelerate/decelerate to that speed. So it's far better to gear to get better acceleration, and make better use of the servos potential rather than limit how fast it spins.

    please correct me if im wrong but im under the illusion that with the servos and driver kit if it "loses steps" ie out of position it will alarm or something to stop inaccurate turning
    It all depends on how you program them, but they should do. There will be a following error parameter, that can trigger a fault when a set number of counts out of position is exceeded.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  8. #8
    i asked a couple of vendors on eBay questions and unfortunately no replies

    so if anyone can recommend a seller of reasonably priced servos and driver kit i would be grateful

    cheers

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. servo and spindle advice please
    By iamspuddy in forum Stepper & Servo Motors
    Replies: 0
    Last Post: 15-02-2021, 07:10 PM
  2. Beam choice
    By idegraaf in forum Gantry/Router Machines & Building
    Replies: 6
    Last Post: 22-03-2018, 06:38 PM
  3. VFD choice
    By D-man in forum Spindles & Drive Motors
    Replies: 7
    Last Post: 20-02-2016, 02:38 PM
  4. CNC router choice out there.
    By CTJ in forum Machine Discussion
    Replies: 0
    Last Post: 10-12-2015, 08:51 PM
  5. eBay: SEM SERVO MOTOR SEM MT30 U4-48, LAMBDA psu,s, 160v servo drive
    By dazza in forum Items On eBay UK
    Replies: 0
    Last Post: 29-01-2015, 07:55 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •