Results 1 to 3 of 3
  1. #1
    Join Date
    Nov 2014
    Location
    Saudi Arabia
    Age
    28
    Posts
    2
    Rep Power
    0

    Angry VRF/VRV exact compressor motor and power type



    Good day everyone.

    I'm currently in the process of exploring the VRF technology in preparation for working in VRF sales
    (my background in in water chillers).

    I've done some reading and questioning here and there, and been able to learn alot
    However, there has been a topic regarding the VRF that no one has given me a clear answer to. Not the internet, not the product manuals, and certainly not the engineers already working in the VRF business. And I was hoping that someone here would be kind enough to explain this to me:

    Is the compressor motor type AC or DC????

    Now, I know that all VRF manufacturers market their product as "DC inverter compressor" based
    But isn't an inverter a device that converts DC to AC (PWM, but still perceived as AC)? Doesn't this make the motor itself AC, and the DC is merely used to produce AC of controllable frequency (and therefore controllable motor speed).

    I took a look at a power wiring diagram of a VRF module and it looked exactly like this:
    3-ph power -> 3-ph bridge rectifier -> (now DC power) -> capacitor and inductor to smoothen the ripple -> Inverter module (IGBT's) -> Motor (3 wires)

    This looked to me exactly like the VSD/VFD configuration

    Does this mean that the "DC inverter compressor" is pretty much just a compressor driven by an AC motor thats modulated by a VSD?
    If so, why don't they market it as VSD? (technically correct term, already well known in the market)

    Also, I recall reading somewhere that the VRF compressors include a permanent magnet, which means that they are NOT induction motors.

    If this is true, then what kind of motors are they?????

    The same applies to condenser fans. The manuals claim that they are DC to enable speed control, but are they?


    Looking forward to your help!



  2. #2
    Brian_UK's Avatar
    Brian_UK is online now Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    69
    Posts
    10,444
    Rep Power
    50

    Re: VRF/VRV exact compressor motor and power type

    Hi Amat and welcome to the forum.

    Hopefully this link will help explain the operation for you.

    http://www.airconditioning-systems.com/dc-inverter.html

    Also, yes they do use DC fan motors, Daikin motors run at 325vdc if I remember correctly.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015
    Please support http://the100project.net/Home

  3. #3
    Join Date
    Nov 2014
    Location
    Saudi Arabia
    Age
    28
    Posts
    2
    Rep Power
    0

    Re: VRF/VRV exact compressor motor and power type

    Quote Originally Posted by Brian_UK View Post
    Hi Amat and welcome to the forum.

    Hopefully this link will help explain the operation for you.

    http://www.airconditioning-systems.com/dc-inverter.html

    Also, yes they do use DC fan motors, Daikin motors run at 325vdc if I remember correctly.

    Thanks for the warm welcom Brian! I'm glad that I can be a part of this community of refrigeration and cooling professionals, and hope to learn a lot from you

    Your link pretty much sums it all up...
    apparently the motor IS DC, however, the brushless DC motor's working principle in similar to that of an AC motor, in the fact that alternating the current between the poles is done by electronic means (inverter) instead of the traditional "brush" in typical DC motors.

    Thanks again mate! you've saved me a lot of headache.
    Searching for info on the VRF on the web directed me to promotional info, not scientific stuff on the working principle.

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
  •