Yaskawa Servo Motor Encoder Alignment


Thread Starter


I have a Yaskawa servo motor SGMSH-20DCA6F. Its key way had damaged so I tried to replace with another Rotor of same servo by installing the previous OK encoder. As I power on the machine after some steps servo gives the error.

Can anybody suggests me how to align the encoder with servo motor?
>The better way is to contact local Yaskawa representative.

This is the BEST that can be done. Servomotors are only serviceable by the manufacturer's shop, but it's usually cheaper to get a new one. Do not expect to disassemble one of these and get it to work. In other words, servomotors are disposable most of the time.


>The better way is to contact local Yaskawa representative.

I don't have the access of Local representative in my city...I was trying to do it myself.
After getting the drive to turn on And the led’s to show everything is working, use the drives power to power the encoder and use an oscilloscope to probe the u,v,w absolute angle positions. Apply 5 or less volts to u and v phases of the motor and align the encoder with the appropriate angle. Mine was 150* electrical degrees. Then lock the encoder to that position and it should work. Also make sure the drive has the correct count encoder. I used a different count on my encoder disc and had to set the jumpers appropriately on my drive for the proper count so the drive knows how many counts 150* is or what ever your particular motor is. Mine is an 8 pole with 2500 line encoder. As long as you have your manual which you can download if you search enough, it’s pretty easy. A dead drive is usually not worth fixing unless an opto isolator goes out which is an easy soldering job.
If you have a 3D printer you can print a new mount for a tomagawa seiki encoder which work great and are pretty inexpensive as they provide everything these expensive $400 encoders do for a fraction of the cost.


Good day all
Before you disassembly the damage motor , you should apply dc voltage(depends on motor , maybe 12V) to motor wire (whatever UV , VW , UW)
then make a sign on the motor stator and motor shaft and the encoder connect shaft.
then you can start to disassembly the motor
after you assembly the motor , you need to apply the dc voltage again the motor wire same as before
then rotor should rotate to the same electrical angle , then alignment the encoder mark to the stator mark.
After that , the system should work.