Motor encoder alignment

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Thread: Motor encoder alignment

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    Default Motor encoder alignment

    Hi,

    What is the best way to realign the encoder with a brushless motor.?
    I had a good brushless with a bad encoder.
    I allready install a new encoder but at hi pps the motor just stops (error from the Rutex drive)

    Thanks

    Dan

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    Community Moderator Al_The_Man's Avatar
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    If your encoder has three simulated 'Hall' tracks, I have done it with a double beam scope, as follows.
    Connect a 10k ¼w resistor to each phase and connect the other three ends together to make a star point. This is you scope common for the first channel and the input lead to the U phase.
    the other 'scope channel is for the hall effect output for the U pulse.
    Rotate the motor either by hand or by some low speed means and a generated sine wave should be observed on the U phase out. The square hall effect pulse should be then aligned with the the centre of the sinewave output.
    The other Hall pulses can be verified the same way with the corresponding motor phase.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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


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    Default aligning hall simulator encoder

    Al,

    Thanks for that info. I wouldn't have been able to answer that, but it seems logical.

    By the way, the R2030 drives are enroute from Australia. I believe I will have them in just a couple of days from now!

    As Vladimir woud say: Cheers,

    Tom Eldredge
    Rutex LLC

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Al: any way you can make a drawing of the layout you describe???

    I'm dyslexic when it comes to 'word problems'. Heck , can't even read a vernier micrometer nor a slide rule. If it hadn't been for TI calculators, would never have gotten thru college.



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    Here is the method, power is to Encoder ONLY. Waveform diag. shows all three waveforms at once.
    Al.

    Attached Thumbnails Attached Thumbnails Motor encoder alignment-halleffect-gif  
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    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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    Default Re: Motor encoder alignment

    Hi friend.
    Plz tell me ,how can oscilloscope shows waveform without moving motor?



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    Default Re: Motor encoder alignment

    You have to rotate the motor in order to generate the waveform, I use a motor to drive them at around 200rpm, not critical.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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    Default Re: Motor encoder alignment

    Thanks for the tip Al.

    Suat
    Proud father, C# developer, Model heli pilot, newbie free time machinist for hobby


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    Default Re: Motor encoder alignment

    Al,
    Say you don't have an oscilloscope. Is there a trick to find the start point of the U phase? Because I have a magnetic encoder and aligning the encoder is very simple by shorting two pins together when the rotor of the spindle is at its starting point. To my understanding the only thing I need to do is to get the rotor to the U phase starting point and short the encoder set-to-zero pins together so the encoder will be aligned to the motor.

    By the way, I have a nice handheld oscilloscope but I never used it. I don't know how to use it.

    Suat
    Proud father, C# developer, Model heli pilot, newbie free time machinist for hobby


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    Default Re: Motor encoder alignment

    Quote Originally Posted by Al_The_Man View Post
    If your encoder has three simulated 'Hall' tracks, I have done it with a double beam scope, as follows.
    Connect a 10k ¼w resistor to each phase and connect the other three ends together to make a star point. This is you scope common for the first channel and the input lead to the U phase.
    the other 'scope channel is for the hall effect output for the U pulse.
    Rotate the motor either by hand or by some low speed means and a generated sine wave should be observed on the U phase out. The square hall effect pulse should be then aligned with the the centre of the sinewave output.
    The other Hall pulses can be verified the same way with the corresponding motor phase.
    Al.
    Hi, is it possible to buy third party encoders with hall sensors or simulated hall sensors, I have never seen them advertised. The reason I ask is because I have a motley collection of AC servo motors with no matched drives and it occurred to me that putting such an encoder on these it should be possible to drive them with generic brushless DC servo's of which I have in abundance, just a thought. Dave



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    Default Re: Motor encoder alignment

    Quote Originally Posted by Bdrangdo View Post
    Hi, is it possible to buy third party encoders with hall sensors or simulated hall sensors, I have never seen them advertised. The reason I ask is because I have a motley collection of AC servo motors with no matched drives and it occurred to me that putting such an encoder on these it should be possible to drive them with generic brushless DC servo's of which I have in abundance, just a thought. Dave
    There are many encoders made this way now as Hall sensors have dropped out of favor now because the simulated hall tracks are much more accurate.
    I used to get mine from Renco, but now they have been taken over by Heidenhain, many of the models have been dropped. But there are many others.
    I have converted Fanuc AC servo motors to BLDC this way.
    You need to know the pole pairs count of the motor, if you short the stator leads and rotate the motor by hand and count the 'bumps' per rev.
    AZALIN, I have never come across a 'Magnetic' encoder as far as I recall.
    Al..

    Last edited by Al_The_Man; 11-06-2018 at 12:27 PM.
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    Default Re: Motor encoder alignment

    By magnetic I mean the encoder has no rotating part, it just senses the rotation of a magnet.

    This one: https://www.rls.si/en/rmc22-commutat...mental-encoder

    Suat
    Proud father, C# developer, Model heli pilot, newbie free time machinist for hobby


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    Default Re: Motor encoder alignment

    Quote Originally Posted by Azalin View Post
    By magnetic I mean the encoder has no rotating part, it just senses the rotation of a magnet.

    This one: https://www.rls.si/en/rmc22-commutat...mental-encoder
    I see, I believe I tried a similar version made by CUI but it was in the early stages of development and I had varying degrees of success with it.
    Those look similar, if so they are self calibrating, i.e. requires no scope to align.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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    Default Re: Motor encoder alignment

    Yes. Just align the rotor to the zero point and set the encoder with a button.

    What I don't know is how to get the rotor to it's zero point. I came across a blog entry today. The poster says if you apply +5vdv to the U phase and - pole to the V phase then the rotor will move to the zero point. Sounded interesting to me.

    Sent from my MI 5s Plus using Tapatalk

    Suat
    Proud father, C# developer, Model heli pilot, newbie free time machinist for hobby


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    Default Re: Motor encoder alignment

    Quote Originally Posted by Al_The_Man View Post
    There are many encoders made this way now as Hall sensors have dropped out of favor now because the simulated hall tracks are much more accurate.
    I used to get mine from Renco, but now they have been taken over by Heidenhain, many of the models have been dropped. But there are many others.
    I have converted Fanuc AC servo motors to BLDC this way.
    You need to know the pole count of the motor, if you short the stator leads and rotate the motor by hand and count the 'bumps' per rev.
    AZALIN, I have never come across a 'Magnetic' encoder as far as I recall.
    Al..
    Thanks for that Al, I will have a look round and see what is available in the UK. Dave



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    Default Re: Motor encoder alignment

    Could you please explain the wiring and voltages? I'm confused if we apply DC voltage to the motor, and or encoder. Without a voltage on the motor windings, how do you find "zero" on the motor? Is it possible to do a slightly modified version of alignment with the motor ON the machine?
    Does the same procedure apply to a Yaskawa AC servo w/8192 Inc encoder?

    Quote Originally Posted by Al_The_Man View Post
    Here is the method, power is to Encoder ONLY. Waveform diag. shows all three waveforms at once.
    Al.




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    Default Re: Motor encoder alignment

    You rotate the BLDC motor in order that it will generate a AC wave form on the 3 phases.
    Both the A phase and the corresponding commutation pulse is monitored on a scope and the encoder turned until the commutation is as is shown on the PDF.
    IOW you check one phase at a time.
    AFAIK the Yaskawa AC servo is just that AC so the BLDC version may not apply as far as alignment .
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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


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