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Thread: Metal Working Spindle

  1. #21
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    Default Re: Metal Working Spindle

    Quote Originally Posted by KiwiEngineer View Post
    Another dumb question incoming haha.

    I cant seem to find the physical difference inside between a 800hz spindle and 400hz one. I thought i could possibly get G-Penny to modify my one? Would this this benefit me how? Or would it have the same torque curve at the same rpm as the 800hz spindle but with a lower top speed?

    Rohan
    Using a VFD Drive that has sensorless Vector Mode you can change the torque to be constant and also a higher torque response, If the VFD Drive is used in V/F mode you have a basic torque curve that you can set

    The wire in the stator should have a better insolation for the 800Hz may even use a thicker wire in the windings, I'm not sure if there would be any difference in performance if you use sensorless Vector mode which will give you better low speed torque

    The spindle you chose will eat Aluminum with out any problems, and with all the right cutting conditions steel will also cut ok with this spindle so not sure why you would want to change anything

    Using sensorless vector mode with the Delta VFD Drive you would still be able to hit the max Amps at the 400Hz

    Mactec54


  2. #22
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    Default Re: Metal Working Spindle

    Hi,
    depending on where in the world you are, or which engineering school you went to there are two different terminologies in use with respect to pole numbers.

    Americans and many Europeans use the idea of poles per phase. A two pole motor has a synchronous speed at 400Hz of 400 revs/sec or 24000 rpm.
    A four pole motor has a synchronous speed at 400 Hz of 200 rev/sec or 12000 rpm. You can see that doubling the number of poles halved the synchronous speed but will
    double the torque. In general the more poles the slower the motor but increasing torque.

    In New Zealand Universities its common to use the term 'pole pair per phase'. Thus an American two pole motor would be called a 'one pole pair per phase' motor here,
    and a four pole motor would be called a 'two pole pair per phase motor'. Pay close attention to the language used in advertising, it may illuminate which terminology is in use.

    I used an Allen Bradley servo which is an eight pole motor (four pole pair per phase), which is common for servos. An AC servo has a rare earth permanent magnet rotor
    and they exhibit class leading torque for a given current. An asynchronous motor like those you are looking at do pretty well but still not up to servo levels.

    You may note the many industrial mills have spindles (asynchronous) of 22kW,25kW,30kW at 12000 rpm or so. These spindles have good torque at low speeds by virtue
    of their huge power rating. You'd never run one on single phase power.

    By all means try one of the spindles you've linked to, they will be great in many situations and you'll use it a lot, but it achillies heel will be high torque at low revs for steel, and
    even then it may surprise you.

    I got lucky and found a second hand 1.8kW servo and drive on Trade-me for $900NZD. I still had to buy the set-up and tuning software, another $200NZD. I bought/made two cables,
    and as the cable plugs are rare as rocking horse poo, they weren't cheap either at $300. I paid $450NZD for a genuine Rego-Fix ER 25 toolholder and $200NZD for P4 matched pairs of angular
    contact bearings. As you can see making your own spindle is not cheap, but I'm happy with the result, and its probably better than I could have bought outright.

    The truth is though that for every hour I use it I use my highspeed spindle for 20 hours. I would suggest invest in a good highspeed spindle.......experiment with it at low speed
    BEFORE deciding on what you want. For the amount I use mine it was not worth it. That may change with my new build mill which is many MANY times more rigid than my mini-mill
    and so I will be able to extract everything from the low speed spindle that I've been unable to tap into with the mini-mill.

    Craig



  3. #23

    Default Re: Metal Working Spindle

    Quote Originally Posted by mactec54 View Post
    Using a VFD Drive that has sensorless Vector Mode you can change the torque to be constant and also a higher torque response, If the VFD Drive is used in V/F mode you have a basic torque curve that you can set

    The wire in the stator should have a better insolation for the 800Hz may even use a thicker wire in the windings, I'm not sure if there would be any difference in performance if you use sensorless Vector mode which will give you better low speed torque

    The spindle you chose will eat Aluminum with out any problems, and with all the right cutting conditions steel will also cut ok with this spindle so not sure why you would want to change anything

    Using sensorless vector mode with the Delta VFD Drive you would still be able to hit the max Amps at the 400Hz
    I noticed the Fuling VFD's come with both modes. I know its not my first choice of VFD but i dont really have many options as i cant source the Delta or Yaskawa alternatives.

    The 2.2kw VFD they suggest is actually a 10A output not 7A as it states in the title. Would this one be better to go with instead of the 3.7kw older brother (15A)? To note there is a massive size difference as well. But if you think its worth it ill go for it.

    https://www.aliexpress.com/item/1005...44a07bbbZ1wzjl

    https://www.aliexpress.com/item/1005...44a07bbbZ1wzjl



  4. #24

    Default Re: Metal Working Spindle

    Quote Originally Posted by joeavaerage View Post
    Hi,
    depending on where in the world you are, or which engineering school you went to there are two different terminologies in use with respect to pole numbers.

    Americans and many Europeans use the idea of poles per phase. A two pole motor has a synchronous speed at 400Hz of 400 revs/sec or 24000 rpm.
    A four pole motor has a synchronous speed at 400 Hz of 200 rev/sec or 12000 rpm. You can see that doubling the number of poles halved the synchronous speed but will
    double the torque. In general the more poles the slower the motor but increasing torque.

    In New Zealand Universities its common to use the term 'pole pair per phase'. Thus an American two pole motor would be called a 'one pole pair per phase' motor here,
    and a four pole motor would be called a 'two pole pair per phase motor'. Pay close attention to the language used in advertising, it may illuminate which terminology is in use.

    I used an Allen Bradley servo which is an eight pole motor (four pole pair per phase), which is common for servos. An AC servo has a rare earth permanent magnet rotor
    and they exhibit class leading torque for a given current. An asynchronous motor like those you are looking at do pretty well but still not up to servo levels.

    You may note the many industrial mills have spindles (asynchronous) of 22kW,25kW,30kW at 12000 rpm or so. These spindles have good torque at low speeds by virtue
    of their huge power rating. You'd never run one on single phase power.

    By all means try one of the spindles you've linked to, they will be great in many situations and you'll use it a lot, but it achillies heel will be high torque at low revs for steel, and
    even then it may surprise you.

    I got lucky and found a second hand 1.8kW servo and drive on Trade-me for $900NZD. I still had to buy the set-up and tuning software, another $200NZD. I bought/made two cables,
    and as the cable plugs are rare as rocking horse poo, they weren't cheap either at $300. I paid $450NZD for a genuine Rego-Fix ER 25 toolholder and $200NZD for P4 matched pairs of angular
    contact bearings. As you can see making your own spindle is not cheap, but I'm happy with the result, and its probably better than I could have bought outright.

    The truth is though that for every hour I use it I use my highspeed spindle for 20 hours. I would suggest invest in a good highspeed spindle.......experiment with it at low speed
    BEFORE deciding on what you want. For the amount I use mine it was not worth it. That may change with my new build mill which is many MANY times more rigid than my mini-mill
    and so I will be able to extract everything from the low speed spindle that I've been unable to tap into with the mini-mill.

    Craig
    Thanks for all the info!

    The set up you have described sounds amazing! Who knows, maybe in future i could do something similar if i find my router is ridged enough to cope with milling steel. Is your spindle belt driven? or directly mounted by a coupling?

    For now i think ill try what ive ordered. If it doesnt work out i can always put it on Trademe and get my money back. (As you know these type of things are limited to buy here)

    Rohan



  5. #25
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    Default Re: Metal Working Spindle

    Quote Originally Posted by KiwiEngineer View Post
    I noticed the Fuling VFD's come with both modes. I know its not my first choice of VFD but i dont really have many options as i cant source the Delta or Yaskawa alternatives.

    The 2.2kw VFD they suggest is actually a 10A output not 7A as it states in the title. Would this one be better to go with instead of the 3.7kw older brother (15A)? To note there is a massive size difference as well. But if you think its worth it ill go for it.

    https://www.aliexpress.com/item/1005...44a07bbbZ1wzjl

    https://www.aliexpress.com/item/1005...44a07bbbZ1wzjl
    If it has a single phase rating 230v /240v then then it would be ok, but is at it's max then for your spindle

    Mactec54


  6. #26
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    Default Re: Metal Working Spindle

    Quote Originally Posted by joeavaerage View Post
    Hi,
    depending on where in the world you are, or which engineering school you went to there are two different terminologies in use with respect to pole numbers.

    Americans and many Europeans use the idea of poles per phase. A two pole motor has a synchronous speed at 400Hz of 400 revs/sec or 24000 rpm.
    A four pole motor has a synchronous speed at 400 Hz of 200 rev/sec or 12000 rpm. You can see that doubling the number of poles halved the synchronous speed but will
    double the torque. In general the more poles the slower the motor but increasing torque.

    In New Zealand Universities its common to use the term 'pole pair per phase'. Thus an American two pole motor would be called a 'one pole pair per phase' motor here,
    and a four pole motor would be called a 'two pole pair per phase motor'. Pay close attention to the language used in advertising, it may illuminate which terminology is in use.

    I used an Allen Bradley servo which is an eight pole motor (four pole pair per phase), which is common for servos. An AC servo has a rare earth permanent magnet rotor
    and they exhibit class leading torque for a given current. An asynchronous motor like those you are looking at do pretty well but still not up to servo levels.

    You may note the many industrial mills have spindles (asynchronous) of 22kW,25kW,30kW at 12000 rpm or so. These spindles have good torque at low speeds by virtue
    of their huge power rating. You'd never run one on single phase power.

    By all means try one of the spindles you've linked to, they will be great in many situations and you'll use it a lot, but it achillies heel will be high torque at low revs for steel, and
    even then it may surprise you.

    I got lucky and found a second hand 1.8kW servo and drive on Trade-me for $900NZD. I still had to buy the set-up and tuning software, another $200NZD. I bought/made two cables,
    and as the cable plugs are rare as rocking horse poo, they weren't cheap either at $300. I paid $450NZD for a genuine Rego-Fix ER 25 toolholder and $200NZD for P4 matched pairs of angular
    contact bearings. As you can see making your own spindle is not cheap, but I'm happy with the result, and its probably better than I could have bought outright.

    The truth is though that for every hour I use it I use my highspeed spindle for 20 hours. I would suggest invest in a good highspeed spindle.......experiment with it at low speed
    BEFORE deciding on what you want. For the amount I use mine it was not worth it. That may change with my new build mill which is many MANY times more rigid than my mini-mill
    and so I will be able to extract everything from the low speed spindle that I've been unable to tap into with the mini-mill.

    Craig
    No there is one standard when it come to engineering, no matter where you are in the world, the only difference is some understand and use it better than others

    With respect to the Pole count, how it is written both ways is quite normal to see, they both mean the same thing, one is less confusing to those that don't know much about Ac motors in general

    Again you seem to be quoting something that is not related to what this spindle is about, 2.2Kw 10A 4 Pole ( 2 Pole Pair ) 24,000 =800Hz

    Mactec54


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