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  1. #1
    Join Date
    Nov 2016
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    Sweden
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    What kind of 3 phase motor in minisplit compressor?

    Modern minisplits has a 3 phase compressor but is it a brushless DC motor or a regular 3 phase induction motor? I'm trying to run the compressor with a VFD (variable frequency driver) motor controller but that does not work very well. What is the difference between brushless DC 3 phase and regular 3 phase? Is there VFDs for BLDC motors that might do a better job driving the scroll compressor?

  2. #2
    Join Date
    Jul 2013
    Location
    Richmond, VA
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    Inverter-driven mini splits are brushless 3-phase DC motors, the inverter controls the frequency and voltage. It depends on what you have in front of you, but Mitsubishi has some extensive information at mylinkdrive.com. I wouldn't know where to start with bench-testing a compressor with a VFD, but I'm thinking it could be done.

  3. #3
    Join Date
    Nov 2016
    Location
    Sweden
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    Thread Starter
    Seems like brushless DC needs some kind of sync control. With my VFD for induction motors I can get the compressor to start and ramp up to about 30 hz but then current gets too high and it cuts out. Meassuring 15A on the 3 phase cables and about 5A in the 1 phase 230 volt in. In other words the VFDs output is low volt high amp for some reason. Dont know why but I guess alot of the juice is working against itself due to lack of sync.

  4. #4
    Join Date
    Nov 2016
    Location
    Sweden
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    Thread Starter
    Mylinkdrive seems to be a goldmine. They do block Sweden so you have to use a proxy to get access. In what department do I start looking for technical stuff like inverters and compressors? And thank you for this link. in Sweden they try to hide knowlege from people. Only the chosen few may have such info.

  5. #5
    Join Date
    Jul 2013
    Location
    Richmond, VA
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    Quote Originally Posted by Malmen View Post
    Mylinkdrive seems to be a goldmine. They do block Sweden so you have to use a proxy to get access. In what department do I start looking for technical stuff like inverters and compressors? And thank you for this link. in Sweden they try to hide knowlege from people. Only the chosen few may have such info.
    Find the outdoor unit your compressor might be from, then look at the service manual. They’re very comprehensive.


    Sent from my iPhone using Tapatalk

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