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Thread: Sako VFD

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  1. #1
    ericks Guest

    Sako VFD

    Hi guys, i thought i would let you know about my experience with a Sako 2.2 Kw, 230V single phase input drive. Received it yesterday, the unit looked okay. Tested it at work just now.
    It failed the test cause this drive can be potentially dangerous. It works fine on certain deceleration times....on some dec times the drive would speed up past the max setting when stopped or "told" to speed down. I had to kill the power to the drive to stop it accelerating

  2. #2
    Join Date
    Jan 2005
    Posts
    15362

    Re: Sako VFD

    Quote Originally Posted by ericks View Post
    Hi guys, i thought i would let you know about my experience with a Sako 2.2 Kw, 230V single phase input drive. Received it yesterday, the unit looked okay. Tested it at work just now.
    It failed the test cause this drive can be potentially dangerous. It works fine on certain deceleration times....on some dec times the drive would speed up past the max setting when stopped or "told" to speed down. I had to kill the power to the drive to stop it accelerating
    A video would of been good

    Where you running a 24,000 RPM Spindle motor or something else

    You also may have damaged it without having the correct Parameters set on startup

    It sounds though that it needed a Braking Resistor to do what you where trying to do, if your spindle was at 24,000 RPM this can be a challenge for any VFD when Decelerating to fast without a Breaking Resistor
    Mactec54

  3. #3
    ericks Guest

    Re: Sako VFD

    Quote Originally Posted by mactec54 View Post
    A video would of been good

    Where you running a 24,000 RPM Spindle motor or something else

    You also may have damaged it without having the correct Parameters set on startup

    It sounds though that it needed a Braking Resistor to do what you where trying to do, if your spindle was at 24,000 RPM this can be a challenge for any VFD when Decelerating to fast without a Breaking Resistor
    Mac...i programmed it for a standard four pole (1440 rpm) motor. There was no problem with the settings....seems its affected by it's own noise. When i reduce the dec time less than 5 seconds it works fine. It seems to be either firmware or noise problems Must be honest i didn't expect much of a $100 drive anyway

  4. #4
    ericks Guest

    Re: Sako VFD

    I had another look at the operation of the drive. I am convinced the problem is firmware related. It does not want me to go above 4.8 sec dec otherwise it speeds up on the stop command and keeps speeding up. I am able to stop my 2.2 Kw test motor all the way down to 0.5 seconds dec ? without the drive tripping...which is actually very good. Besides the speeding up at certain dec values the drive performs quite well.

  5. #5
    ericks Guest

    Re: Sako VFD

    Update....although what happened should not be able to happen, that is the drive speeding up on stopping above the max value. I managed to get it to work properly. There is a parameter (Deceleration voltage limiting coefficient) Default is 100.....setting values are 0 - 255....i adjusted it to 50, now i am able to select log dec and all work as expected

  6. #6
    Join Date
    Jan 2005
    Posts
    15362

    Re: Sako VFD

    Quote Originally Posted by ericks View Post
    Update....although what happened should not be able to happen, that is the drive speeding up on stopping above the max value. I managed to get it to work properly. There is a parameter (Deceleration voltage limiting coefficient) Default is 100.....setting values are 0 - 255....i adjusted it to 50, now i am able to select log dec and all work as expected
    That's good you did find something, when you say Deceleration voltage limiting, this is normally controlled as Dc Braking which is needed sometimes, depending on the load inertia the motor is creating

    Yes there are some good prices out there for VFD Drives, I saw that same drive at $61 so would close to the same as what you paid in Aussie Dollars
    Mactec54

  7. #7
    ericks Guest

    Re: Sako VFD

    Quote Originally Posted by mactec54 View Post
    That's good you did find something, when you say Deceleration voltage limiting, this is normally controlled as Dc Braking which is needed sometimes, depending on the load inertia the motor is creating

    Yes there are some good prices out there for VFD Drives, I saw that same drive at $61 so would close to the same as what you paid in Aussie Dollars
    I tested it on a standard rcd protected power supply, no issues. I will inform them about the accelerating issue....it's something they should look at, a drive should never accelerate on it's own past set limits...no matter what parameters you set. Usually if you select wrong/bad values the drive will either stop you with an error or trip (anyway with default values and running no load there should be no such issues). Must say that during testing the drive never heated up.....i managed a lot of low speed torque as well

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