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IndustryArena Forum > CNC Electronics > Servo Motors / Drives > Yaskawa Ac Servo encoder re alignment
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  1. #1
    Join Date
    Dec 2009
    Posts
    166

    Yaskawa Ac Servo encoder re alignment

    Hi Guys
    I just replaced the bearings on one of my yaskawa sgmp-08a312 ac servo and now is seems that the encoder needs to be re aligned
    I removed the encoder with great care it is fixed to the motor shaft via a morse tapper you insert a bolt to pull it from the shaft this all went well with no problems as did the bearing replacement .
    How ever on run up it now come up with a over run error .
    Checking some youtube videos is seems that there has to be 199 degrees between the u to v phase and 259 degrees between the u to w phase
    I have a Tekronix 2456B scope .
    So the big question is does anybody know how to achieve this alignment
    Thanks .

  2. #2
    Join Date
    Dec 2003
    Posts
    24216

    Re: Yaskawa Ac Servo encoder re alignment

    I assume this is the commutation tracks on the encoder?
    If so, what is the nature of the feedback? Pulse(s)?
    In all likely hood it is a AC servo and not BLDC, both motors are essentially identical, just the commutation differs.
    Unfortunately I only have the process for BLDC.
    This is done by powering the encoder and back driving the motor so it generates, and displaying the feedback and the encoder output on a double beam 'scope.
    And turn the encoder until alignment is achieved.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  3. #3
    Join Date
    Dec 2009
    Posts
    166

    Re: Yaskawa Ac Servo encoder re alignment

    Yes in my post I state that this is a ac servo I do have a 4 channel Tekronix scope 2465B I aslo have 2 other identical servos in perfect working order
    As a hack I could back drive one of my other units and try to set up the faulty one to look the same on my scope unless you have some other method
    cheers thanks for the reply.

  4. #4
    Join Date
    Dec 2003
    Posts
    24216

    Re: Yaskawa Ac Servo encoder re alignment

    If the encoder commutation is serial, this method won't work, but it is worth a shot to take a look at the waveform, I used ~ 200rpm for back driving.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  5. #5

    Re: Yaskawa Ac Servo encoder re alignment

    I am in the process of trying to align a UTOPH-81AWF Incremental Encoder (P/N UPG000116) with my Yaskawa SGMG-03A2AB AC Servo Motor. In your process above, you suggested backdriving the motor and aligning it with the encoder output. Which channel on the encoder should be aligned (A, B, or Z)?

    Also, does anyone have a pinout of this encoder?

  6. #6
    Join Date
    Dec 2003
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    24216

    Re: Yaskawa Ac Servo encoder re alignment

    I back drive about 100-200rpm.
    Any phase can be aligned with its associated commutation pulse.
    This is for motors that have hall effect or simulated type on the encoder track.
    You have to use a D.B. scope and set up a virtual neutral point by connecting a 1k to 10k resistor to each phase lead and connect the other ends together, this is your virtual neutral for one ch of the scope.
    Al.
    Renco diagram attached.
    Attached Files Attached Files
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  7. #7
    Join Date
    Dec 2009
    Posts
    166

    Re: Yaskawa Ac Servo encoder re alignment

    Okay I found a faulty chip on my Yaskawa encoder the chip no is "Yaskawa jl-041a" after replacing this chip and re-aligning the phases I am happy to report this motor is now working perfectly thanks for all the help

  8. #8

    Re: Yaskawa Ac Servo encoder re alignment

    Quote Originally Posted by squirrel_41 View Post
    Okay I found a faulty chip on my Yaskawa encoder the chip no is "Yaskawa jl-041a" after replacing this chip and re-aligning the phases I am happy to report this motor is now working perfectly thanks for all the help

    Hello ,
    I have a motor identical to yours with the same alignment problem.
    Please if you can send me the alignment procedure,
    Thanks !

  9. #9
    Join Date
    Dec 2009
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    166

    Re: Yaskawa Ac Servo encoder re alignment

    Its pretty much the same as Al_The_Man says you do need a scope to check the alignment and the pulse
    I back run mine with just a small 12 volt dc motor with a belt drive on the scope you easily see if pulse timing is incorrect and you can adjust with the trim pots
    you don't need the resistors for this drive there are test points that can be easily probed on the mainboard.

  10. #10

    Re: Yaskawa Ac Servo encoder re alignment

    Quote Originally Posted by squirrel_41 View Post
    Its pretty much the same as Al_The_Man says you do need a scope to check the alignment and the pulse
    I back run mine with just a small 12 volt dc motor with a belt drive on the scope you easily see if pulse timing is incorrect and you can adjust with the trim pots
    you don't need the resistors for this drive there are test points that can be easily probed on the mainboard.

    Hello
    Thanks for the reply
    I did as Al_The_Man said.
    I put resistors on the motor in the U.V.W and got the back emf signal as it is in the document and it corresponds to the speed of rotation, but at the output of the encoder there are 4096 pulses I think, and you have no way to align them on the sinus.
    I tried another method, I blocked the DC motor on phase + U and -W and the encoder has 2 holes that can hold it in position.
    Now it is mounted on the machine and it works but gives errors about 20 minutes
    At the moment I am working with the machine and I use it that way.
    However, I do not understand how not to use resistors.
    How do I get feedback from the engine or use all the signals on the U.V.W encoder as measurement points?
    On the encodes I observed U.V.W measurement points but also A.B.Z they are used.
    I do not know what I did is good or not that the encoder was defective and I repaired it, but when checking with the oscilloscope it had some noise on the signal, it may not be properly aligned or a capacitor.
    Please explain that I did not understand how to do it.
    When I finish the job I will align it as you do.
    Thanks

  11. #11
    Join Date
    Dec 2009
    Posts
    166

    Re: Yaskawa Ac Servo encoder re alignment

    When I get 5 mins to spare I will set my motor up on the scope and takes pics of the probe points and the scope it may take me a few days.
    cheers !

  12. #12

    Re: Yaskawa Ac Servo encoder re alignment

    Hello
    For those interested
    Alignment encoder
    for yaskawa SGMP-15a312
    The blue and red phases are fed with dc current, respectively blue -, red + with unlocked brake, when the rotor is aligned on the poles, it is blocked with brake
    Next step, Rotate the encoder rotor to match the 2 holes in the PCB and insert 2 clips and secure.
    Put the screws
    Attention, the red sign in the center of the encoder must correspond approximately to the notation 1 IC Or the YASKAWA logo on the PCB, if the sign does not exist, try with the rotor at 180 *
    This alignment is very precise,

  13. #13
    Join Date
    Mar 2014
    Posts
    1131

    Re: Yaskawa Ac Servo encoder re alignment

    Quote Originally Posted by Dorin1963 View Post
    Hello
    For those interested
    Alignment encoder
    for yaskawa SGMP-15a312
    The blue and red phases are fed with dc current, respectively blue -, red + with unlocked brake, when the rotor is aligned on the poles, it is blocked with brake
    Next step, Rotate the encoder rotor to match the 2 holes in the PCB and insert 2 clips and secure.
    Put the screws
    Attention, the red sign in the center of the encoder must correspond approximately to the notation 1 IC Or the YASKAWA logo on the PCB, if the sign does not exist, try with the rotor at 180 *
    This alignment is very precise,
    Hi,
    What phases are the red and blue wires on your servo?

    I have an electromagnetic encoder installed on my servo. Alignment is very simple. Just lock the rotor by applying 12vDC to two phases and short the 2 pins on the encoder. Done! I did this before and it worked great for 2 years.

    Now I replaced the bearings and I need to do the same again but I don't remember which phases whey were to power to lock.

    Thanks.

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