VFD for 400v motor in wye/star configuration (EU)
Close
Login to Your Account
Results 1 to 8 of 8
  1. #1
    Join Date
    Dec 2019
    Country
    SWEDEN
    Posts
    11
    Post Thanks / Like
    Likes (Given)
    8
    Likes (Received)
    1

    Default VFD for 400v motor in wye/star configuration (EU)

    Hello.

    Sorry for this total newbie question, but knowledge about this was beyond what the old timey electricians out here in the swedish sticks could answer (i realize my handle is Pete Denmark. I am danish, but live in Sweden ).

    I have hurt my back, so i'm bound to a wheelchair for now, som changing belts on my pillar drill press, to alter speed, is near impossible.

    So i wanted to install a VFD. It's a 1000W 50 hZ 400v 3-phase machine (4-pole 1400 RPM).

    I was watching all kinds of tutorials, but it seems all the people posting from outside the US have wired their 3 phase motor in a Delta configuration, so their motor will accept 3x230v power.
    My machine however, is a hardwired 400v in a Wye/star configuration - no delta possible.

    So my total newb question is:
    Can i just buy a 1.5kW 400v 3-phase VFD and hook that up? My guess is yes, since power draw is power draw no matter how the electricity goes over the windings, and as long as the output current from the VFC matches the input current on the moter, things should work, but i'm totally unfamiliar with the intricacies of VFD (numerous YouTube videos have given me SOME idea), so i figured i would ask the experts, before spending money.

    Thank you for your patience .
    Last edited by PeteDenmark; 12-07-2019 at 02:57 AM.

  2. #2
    Join Date
    Jul 2014
    Location
    MI USA
    Posts
    918
    Post Thanks / Like
    Likes (Given)
    199
    Likes (Received)
    376

    Default

    You could post a photo of your motor data plate and a shot of the connection block, so we could see what your working with. Is this statement really true?

    is a hardwired 400v in a Wye/star configuration - no delta possible
    Can you tell us what your supply voltage and configuration is?

    SAF Ω

  3. Likes PeteDenmark liked this post
  4. #3
    Join Date
    Aug 2014
    Location
    bainbridge island
    Posts
    1,180
    Post Thanks / Like
    Likes (Given)
    241
    Likes (Received)
    280

    Default

    You can program a 230v vfd for 230v 35hz and run your motor and get full torque up to about 2/3rds of nominal rpm, and you'll have no problem if you don't need a lot of power, you can get about half a hp or 400 watts out of your 1kw motor at 1750 rpm.

  5. Likes PeteDenmark liked this post
  6. #4
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    18,069
    Post Thanks / Like
    Likes (Given)
    1922
    Likes (Received)
    3058

    Default

    The nominal voltage is, as a standard practice, quoted line-to-line. So if the motor is set up for 230V 3 phase, then it will not matter what the internal structure of the windings is, any motor rated that way is good for 230VAC line-to-line..

    You have a 400V motor. So it would be happy with a 400V 3 phase supply. Yes, that re-wiring will alter the nominal voltage to 230V.

    But, this seems not reasonable. The standard 230V 3 phase in europe is 230V WYE.... in other words it is 230V from line to neutral. That means it is easy to get 230V single phase. But that 3 phase is 400V line-to-line.

    And, I understand that 3 phase is pretty commonly available, unlike the US.

    So, the first question here is what is your supply voltage?

    It sounds as if you may have just 230V single phase, and want to use the VFD for making 3 phase as well as speed variation, but is that true?

    How were you running the machine before? If you could run it from 3 phase before, and you just want variable speed without belt changes, then that is easy. A 400V VFD would run off the 3 phase you have, and do variable speed.

    Please explain what supply voltage and number of phases you have now.

  7. Likes PeteDenmark liked this post
  8. #5
    Join Date
    Dec 2019
    Country
    SWEDEN
    Posts
    11
    Post Thanks / Like
    Likes (Given)
    8
    Likes (Received)
    1

    Default

    Thank you for your kind replies.

    I'm sorry i was unclear. I do have a 3-phase 400v supply in my shop, and the motor is running on that, as stated in a hard wired WYE configuration. 3 phases and ground (as JST said 3x230v with 230v between line and ground, and 400v between lines).
    It actually has a dpdt switch, that reverses two poles, so the drill can run i reverse.

    It's a bit unusual to have hard wired WYE motor. Normally you have a connection block with 6 terminals where you can wire the motor in either 3x230v delta or 400v wye, but not on my machine's motor, even if it is quite "new" from 1995 .

    But according to JST, i should be able to run that motor of a 400v VFD no problem.

    And yes - all i want is the ability to change speed, without swapping belts around. Even before i was injured, it was a pain to constantly have to fiddle with that, when changing drill sizes, or using holesaws. And when using a 150mm hole saw, the lowest speed of 125 rpm simply isn't slow enough.

    I've uploaded photos of all the information that is written on the drill

    20191206_150734.jpg 20191205_171731.jpg 20191206_185600.jpg 20191206_150912.jpg 20191206_191001.jpg

  9. #6
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    18,069
    Post Thanks / Like
    Likes (Given)
    1922
    Likes (Received)
    3058

    Default

    Be aware that slowing via a VFD is not problem free.

    The problem that is most troublesome is that you do not change torque when you slow the motor with a VFD. So the power available is proportional to the speed.

    But with belt changes, the power is pretty constant. The belt change slows the spindle, but it multiplies the torque by the inverse factor.... slowing spindle to 1/3 of the rpm with a belt shift will multiply the torque by about 3x. So the power is constant.

    You may find that slowing via the VFD makes the machine pretty weak with a 150mm hole saw.

  10. Likes PeteDenmark liked this post
  11. #7
    Join Date
    Dec 2019
    Country
    SWEDEN
    Posts
    11
    Post Thanks / Like
    Likes (Given)
    8
    Likes (Received)
    1

    Default

    Quote Originally Posted by JST View Post
    Be aware that slowing via a VFD is not problem free.

    The problem that is most troublesome is that you do not change torque when you slow the motor with a VFD. So the power available is proportional to the speed.

    But with belt changes, the power is pretty constant. The belt change slows the spindle, but it multiplies the torque by the inverse factor.... slowing spindle to 1/3 of the rpm with a belt shift will multiply the torque by about 3x. So the power is constant.

    You may find that slowing via the VFD makes the machine pretty weak with a 150mm hole saw.
    You make a fair point - thank you. I will keep that in mind.

    Right now the drill has three pulleys, and as luck would have it, my two most used speeds require me to move both belts, to swap.
    With a VFD i will retain two pulleys (with one belt), so i can still swap belts. So if i have to use a 150mm hole saw (which is very rarely), i will still have to swap the belt.

    Most of the holes i drill is between 4mm and 13mm, so as long as i can change speeds between 500 and 1500 rpm, i'll be a happy man.

    But you are right i will lose some torque. But this being a 1000 watt motor, it has enough reserve, to handle the torque reduction, and still get through the stuff i drill.

  12. #8
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    18,069
    Post Thanks / Like
    Likes (Given)
    1922
    Likes (Received)
    3058

    Default

    Quote Originally Posted by PeteDenmark View Post
    .....

    Most of the holes i drill is between 4mm and 13mm, so as long as i can change speeds between 500 and 1500 rpm, i'll be a happy man.
    .....
    That range is reasonable, and will probably keep you out of trouble on cooling, also. Slower motor speed leads to less fan cooling as well, but 3:1 is reasonable.

    You can also over-speed somewhat. By having the faster speed attained by setting frequency up over 60 (50) Hz, you can keep better power at the slow speed, since it is not as slow relative to rated speed..

  13. Likes PeteDenmark liked this post

Tags for this Thread

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
  •