540,707 active members*
6,837 visitors online*
Register for free
Login
IndustryArena Forum > CNC Electronics > Spindles / VFD > Spindle + VFD Questions
Results 1 to 6 of 6
  1. #1
    Member
    Join Date
    Aug 2015
    Posts
    11

    Spindle + VFD Questions

    Hi all,

    So I'll try and make this short and concise. I'm going around in circles researching spindles and VFD'S, and could use some help.

    I'm looking at a 4kw air cooled spindle, JGF-4.0KW.
    I have found them with and without a VFD.

    1. Should a vfd be rated for twice the motor current rating?

    2. What is the calculation or low end speed I should expect to be able to get from the 4kw spindle?

    (The top rated speed is 18,000rpm, would I be hoping for something impossible if I needed my low end speed between 5-6,000 rpm?)

    Thank you for your time,

    Travis

  2. #2
    Gold Member
    Join Date
    Apr 2004
    Posts
    5280

    Re: Spindle + VFD Questions

    If you're feeding it single-phase current, then 2x would probably be a good idea. If you've got native 3-phase, it's overkill. Figure the thing will work at about half the top speed, but not below that. The torque falls off and the fan's less effective, which can kill an air-cooled spindle. On yours, figure 10k rpm as a safe low-end speed.
    Andrew Werby
    Website

  3. #3
    Member
    Join Date
    Aug 2015
    Posts
    11
    Quote Originally Posted by awerby View Post
    If you're feeding it single-phase current, then 2x would probably be a good idea. If you've got native 3-phase, it's overkill. Figure the thing will work at about half the top speed, but not below that. The torque falls off and the fan's less effective, which can kill an air-cooled spindle. On yours, figure 10k rpm as a safe low-end speed.

    Thank you for response, and yes I'm running on single phase, 220v. So I should expect to run a vfd rated at twice the amps for single phase to get the full range of rpm from the spindle. As far as the 10,000 rpm lower end limit, does that change if you use a water cooled spindle? Or is that a torque fall off below that?

    Also one last question, other than buying a mafell or amb, does anyone know of a spindle that will range between 5,000-18,000 rpm?

    Thank you again for your time,

    Travis

  4. #4
    Community Moderator ger21's Avatar
    Join Date
    Mar 2003
    Posts
    35454

    Re: Spindle + VFD Questions

    A 4kw spindle rated at 10 amps is really a 2.2Kw spindle.

    That's probably why it's $299.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  5. #5
    Member
    Join Date
    Jan 2005
    Posts
    12186

    Re: Spindle + VFD Questions

    Quote Originally Posted by ger21 View Post
    A 4kw spindle rated at 10 amps is really a 2.2Kw spindle.

    That's probably why it's $299.
    Unless they have the voltage incorrect that would be a 380v 4Kw 10A
    Mactec54

  6. #6
    Member
    Join Date
    Jan 2005
    Posts
    12186

    Re: Spindle + VFD Questions

    Quote Originally Posted by Blendwood View Post
    Thank you for response, and yes I'm running on single phase, 220v. So I should expect to run a vfd rated at twice the amps for single phase to get the full range of rpm from the spindle. As far as the 10,000 rpm lower end limit, does that change if you use a water cooled spindle? Or is that a torque fall off below that?

    Also one last question, other than buying a mafell or amb, does anyone know of a spindle that will range between 5,000-18,000 rpm?

    Thank you again for your time,

    Travis
    Water cooled spindle are normally 6,000 RPM to 24,000RPM some will go as low as 3,000 RPM depending on manufacture
    Mactec54

  7. #7
    Member
    Join Date
    Aug 2015
    Posts
    11
    Quote Originally Posted by mactec54 View Post
    Water cooled spindle are normally 6,000 RPM to 24,000RPM some will go as low as 3,000 RPM depending on manufacture
    Thanks Mac, I'll have to do a bit more looking

Posting Permissions

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