Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM


Results 1 to 6 of 6

Thread: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

  1. #1

    Default Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    I have a 110V 400Hz 24,000 RPM spindle from Amazon:
    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
    Yes, I know that I should expect low power from a 110V system, but I have some questions to maximize torque so I can use this to machine aluminum.

    1. I'm only running this at 12,000 RPM or less for machining. Will I get more torque by setting the VFD max output to 200Hz so I'll get the full 110V at the typical speeds that I'm running? Looking at typical frequency/voltage graphs it seems like I'm only getting half voltage sent to the spindle for the (roughly half max) speeds that I'm running with the VFD set to output 400Hz for 24k RPM. I assume more voltage through the spindle will help it to get more current and more torque? I also assume that I'll need to make sure my max current output setting from the VFD is within the limits of the spindle, but as long as the current is limited is it safe to run like this without burning up my spindle motor?

    2. I'm wiring 240V to my garage and I plan to use this for my mill in the near future. I know the VFD is made to handle this input, so no worries there. My 110V spindle is the same size and weight as an identical looking spindle sold as part of a 220V set. Some people have said they're actually the same spindle with a different label. What are the chances that I'll burn up my spindle if I set the VFD output to 220V? Normally it's bad to run double voltage through anything, but I don't know if anyone has any actual technical insite to what I've read about them actually being 220V spindles labeled as 110V for average consumers who don't run higher voltage to their shop.

    3. Will I get more power/torque from the spindle using 240V input for my VFD even if I limit output to the 110V that's listed on my spindle? I assume a 120V single phase input gets strained when it's converted to 110V 3 phase output, so I'm wondering if this is a good middle step until I either send 220V to my current spindle or just buy a new 220V spindle.

    4. I see the typical frequency/voltage charts and the settings for intermediate voltage and frequency. Is it bad for the motor to set a higher voltage at a lower speed? I believe the speed is controlled by the frequency, but would it be bad to set the intermediate voltage high (something in the 50V-100V range)?

    It's crazy that they ship these things out with almost no documentation. You'd think there's a solid baseline for any given VFD/Spindle combo that they sell so I'm not sure why it's so poorly documented. I appreciate your expertise and any advice you guys can provide. Thanks!

    Similar Threads:


  2. #2
    Member mactec54's Avatar
    Join Date
    Jan 2005
    Location
    USA
    Posts
    15362
    Downloads
    0
    Uploads
    0

    Default Re: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    Quote Originally Posted by bcomstock View Post
    I have a 110V 400Hz 24,000 RPM spindle from Amazon:
    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
    Yes, I know that I should expect low power from a 110V system, but I have some questions to maximize torque so I can use this to machine aluminum.

    1. I'm only running this at 12,000 RPM or less for machining. Will I get more torque by setting the VFD max output to 200Hz so I'll get the full 110V at the typical speeds that I'm running? Looking at typical frequency/voltage graphs it seems like I'm only getting half voltage sent to the spindle for the (roughly half max) speeds that I'm running with the VFD set to output 400Hz for 24k RPM. I assume more voltage through the spindle will help it to get more current and more torque? I also assume that I'll need to make sure my max current output setting from the VFD is within the limits of the spindle, but as long as the current is limited is it safe to run like this without burning up my spindle motor?

    2. I'm wiring 240V to my garage and I plan to use this for my mill in the near future. I know the VFD is made to handle this input, so no worries there. My 110V spindle is the same size and weight as an identical looking spindle sold as part of a 220V set. Some people have said they're actually the same spindle with a different label. What are the chances that I'll burn up my spindle if I set the VFD output to 220V? Normally it's bad to run double voltage through anything, but I don't know if anyone has any actual technical insite to what I've read about them actually being 220V spindles labeled as 110V for average consumers who don't run higher voltage to their shop.

    3. Will I get more power/torque from the spindle using 240V input for my VFD even if I limit output to the 110V that's listed on my spindle? I assume a 120V single phase input gets strained when it's converted to 110V 3 phase output, so I'm wondering if this is a good middle step until I either send 220V to my current spindle or just buy a new 220V spindle.

    4. I see the typical frequency/voltage charts and the settings for intermediate voltage and frequency. Is it bad for the motor to set a higher voltage at a lower speed? I believe the speed is controlled by the frequency, but would it be bad to set the intermediate voltage high (something in the 50V-100V range)?

    It's crazy that they ship these things out with almost no documentation. You'd think there's a solid baseline for any given VFD/Spindle combo that they sell so I'm not sure why it's so poorly documented. I appreciate your expertise and any advice you guys can provide. Thanks!
    No, they are not the same spindles inside, outside can look much the same, can you run the 110v spindle on 240v that would be interesting.

    You can't make up your own rules, like suppling 240v and trying to restrict the VFD to output 110v, this is not possible

    2.2Kw is not very good on 120v supply, and a 1.5Kw will work better, you can't change the max rated 400Hz and think it will work better, when you do this, you can damage the spindle

    You have a V/H ratio, and this is the only numbers you can use; will it help it can if done correctly, but you got greedy and went with a 2.2Kw spindle which is wimpy when running on 120v so basically junk unless you have a 35A 120v supply it will be very wimpy and there is not much you can do about it

    So, for this to work as a 2.2Kw the VFD Drive would have to output 17A and have a 35A supply @ 120v, so if you get your 120v 35A line up for this you will get it running much better

    Mactec54


  3. #3

    Default Re: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    Thanks for your input. At some point I'll swap out the spindle for a 220V one, feed it with my 240V garage input, and probably gear it down 2:1 so I can run the spindle at full speed and get more torque in the 12k speed that I want for machining. I like the direct-drive setup, but that's probably not the worst compromise.

    Note that I did hear back from the manufacturer and they partially answered some of my questions. They did say that I can connect the VFD to 220V input on my system and the output would be 150V. But then they said the VFD output parameters should still be set to the spindle parameters. The spindle is stamped with 110V, so I switched all of the VFD settings for spindle max voltage accordingly when I did my initial set up last year, but it certainly wasn't set up like this to start. I believe the output was set to 380V when I got it, so I had to go through the menus and change that in several places.



  4. #4
    Member mactec54's Avatar
    Join Date
    Jan 2005
    Location
    USA
    Posts
    15362
    Downloads
    0
    Uploads
    0

    Default Re: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    Quote Originally Posted by bcomstock View Post
    Thanks for your input. At some point I'll swap out the spindle for a 220V one, feed it with my 240V garage input, and probably gear it down 2:1 so I can run the spindle at full speed and get more torque in the 12k speed that I want for machining. I like the direct-drive setup, but that's probably not the worst compromise.

    Note that I did hear back from the manufacturer and they partially answered some of my questions. They did say that I can connect the VFD to 220V input on my system and the output would be 150V. But then they said the VFD output parameters should still be set to the spindle parameters. The spindle is stamped with 110V, so I switched all of the VFD settings for spindle max voltage accordingly when I did my initial set up last year, but it certainly wasn't set up like this to start. I believe the output was set to 380V when I got it, so I had to go through the menus and change that in several places.
    The default can only be what the VFD Drives name plate voltage is, it's not possible to be set at 380v unless the VFD Drive was rated for it, there numbers they are telling you are incorrect also
    what you put in is what you get out of a VFD Drive, so if this VFD was only rated for 120v input and you put 240v input that may be the case, so this would be a worthless exercise as it would not run a 220v spindle very well with 150v

    If you want better Torque at 12,000RPM then you would get a 4-pole spindle motor this will give you double the torque of the same 2-Pole spindle motor

    Mactec54


  5. #5

    Default Re: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    Update: I managed to adjust several VFD settings and improved the mill significantly, and I'm able to make some very nice products, but of course I have a VERY small chip load and need to upgrade my mill to be able to get better output. Any recommendations for a replacement spindle? Some of my thoughts are:

    1. The simple step up would be to just buy a 220V spindle and swap it out (with appropriate power upgrades), but that'll only get me roughly double the torque and they're still much too fast for cutting metal.

    2. I can gear it down 2:1 or even 3:1, so that would get me 4x~6x torque (depending on my gear ratio), and that gets me down to a better metal machining speed anyway. @mactech54 you mentioned a 4 pole motor will run with double torque at half speed, so that seems like a fairly even trade-off for a 2 pole motor geared down 2:1. I plan to run a belt drive anyway so I can put in a pneumatic tool change, and I don't have a good source for 4 pole spindle motors. From a cost/performance benefit am I just as well off buying a 2 pole motor and gearing it down?

    3. My next thought is upsizing the motor to a 3kW or larger spindle. Combining that with the higher voltage and either gearing it down or going with a 4 pole motor should give me a nice bump up in torque. So at that point I just need to look at how heavy I want to go and how to redesign my mill to handle the weight. I'm already planning a redesign so that's not a major concern.

    4. I noticed that on Amazon the largest water-cooled spindle I could find was 3kW. Anything 4kW and up seems to be air-cooled. I generally prefer water-cooled so I don't need to worry about dust, etc. building up on the cooling fans and reducing the cooling performance, but I assume things are what they are for a reason (hopefully because it works fine, not just for lowest cost regardless of performance).

    I appreciate any input you guys may have for where to buy (and what to buy) for my metal cutting CNC mill spindle when I upgrade my mill soon. Thanks.



  6. #6
    Member mactec54's Avatar
    Join Date
    Jan 2005
    Location
    USA
    Posts
    15362
    Downloads
    0
    Uploads
    0

    Default Re: Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

    Quote Originally Posted by bcomstock View Post
    Update: I managed to adjust several VFD settings and improved the mill significantly, and I'm able to make some very nice products, but of course I have a VERY small chip load and need to upgrade my mill to be able to get better output. Any recommendations for a replacement spindle? Some of my thoughts are:

    1. The simple step up would be to just buy a 220V spindle and swap it out (with appropriate power upgrades), but that'll only get me roughly double the torque and they're still much too fast for cutting metal.

    2. I can gear it down 2:1 or even 3:1, so that would get me 4x~6x torque (depending on my gear ratio), and that gets me down to a better metal machining speed anyway. @mactech54 you mentioned a 4 pole motor will run with double torque at half speed, so that seems like a fairly even trade-off for a 2 pole motor geared down 2:1. I plan to run a belt drive anyway so I can put in a pneumatic tool change, and I don't have a good source for 4 pole spindle motors. From a cost/performance benefit am I just as well off buying a 2 pole motor and gearing it down?

    3. My next thought is upsizing the motor to a 3kW or larger spindle. Combining that with the higher voltage and either gearing it down or going with a 4 pole motor should give me a nice bump up in torque. So at that point I just need to look at how heavy I want to go and how to redesign my mill to handle the weight. I'm already planning a redesign so that's not a major concern.

    4. I noticed that on Amazon the largest water-cooled spindle I could find was 3kW. Anything 4kW and up seems to be air-cooled. I generally prefer water-cooled so I don't need to worry about dust, etc. building up on the cooling fans and reducing the cooling performance, but I assume things are what they are for a reason (hopefully because it works fine, not just for lowest cost regardless of performance).

    I appreciate any input you guys may have for where to buy (and what to buy) for my metal cutting CNC mill spindle when I upgrade my mill soon. Thanks.
    The bigger you go in KW size the more Power requirements you require a 2.2Kw normally has a 30A 240v circuit requirement what do you have for your power supply, if you want low speed then you may be better with an AC servo motor and drive

    Mactec54


Tags for this Thread

Posting Permissions

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


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM

Maximizing Spindle Torque When Only Running a 24k RPM spindle at 12k RPM