Precision Zone specializes in Yaskawa product repairs servicing a wide range of AC Servo series such as Yaskawa SGMS Sigma 1 Series Motors.

The Sigma One Series from Yaskawa was on the leading edge of motion control technology in the 1990’s and Yaskawa continues to be a leader in motion controls. The SGMS series of motors was used primarily in CNC machines and factory automation. This series can be equipped with either an incremental or absolute encoder depending on the demands of the machine. Yaskawa servo motors allow precise movement at high speed with repeatable results.

When assessing the functionality of a motor, our engineering team typically conducts a six-step check:

• Visual Overview Check
• Static Test
• Back EMF
• Feedback Check
• Alarm Code Troubleshooting
• Disassembly and Cleaning

This overview is Precision Zone’s basic troubleshooting process. Once our repair team starts on the job we use specialized, customized test fixtures, SKF Baker AVAIV-4, Huntron tracker, signal generator, oscilloscope, milli and mega ohm meters and other necessary tools to assure quality repair. Most importantly, every repair is fully tested in custom-built simulators under load to replicate real-life working environment.

REPAIR EVALUATION PROCESS FOR SGMS Sigma 1 SERVO MOTOR

Visual Overview Check

When conducting a visual check, the technician inspects the motor for any mechanical damage to the power connecter, junction box, rotor shaft, oil seals and encoder covers. During the visual inspection the technician notes excessive dirt, oil or grease on cooling fans and all other parts of the motor.

Static Test Basic

Precision Zone repair technicians use an SKF Baker Advanced Winding Analyzer to fully evaluate the stator winding. The SKF Baker performs a wide range of electrical tests, including surge, DC hipot, meg-Ohm and winding resistance tests. In the instance of winding resistance each phase is tested with each other; and the mega ohm readings should be no less than 300 mega ohms.

Winding Resistance Testing

Reading should be balanced across all three phases.

Mega Ohm Testing

Back EMF Check

If a servo motor passes the static checks it will be back driven and have the back EMF checked. With our in house magnetizing service we can bring back to life servo motors with weak magnets.

Feedback Check

Repair technicians can test encoders in a number of different ways. Our Mitchell Electrics TI-5000EX system can be used to read, write and record encoder count and data information. We have Mitchell Electrics TI-5250 systems that can be used to see live encoder pulses on an oscilloscope. Connecting encoders directly to the manufacture’s drive is another way we can verify if an encoder is working correctly.

Alarm Codes Troubleshooting

Alarms that the Sigma 1 Series Servopack will display when the SGMS Sigma 1 Series Motors have a problem are the following. These codes displayed are :

Disassembly and Cleaning

All motors are fully dissembled washed and baked. Rotors are checked for bent shafts and bearing journal common problems. The stator winding is rechecked after the baking process. Holding brakes are refurbished and the holding torque is checked. Both the drive end and opposite drive end housing bearing surfaces are checked. Once the evaluation is completed a computer report is generated with all the findings.