Precision Zone is Your Expert Repair Team for Fanuc AC Servo Motor Alpha Series

Precision Zone specializes in Fanuc product repairs servicing a wide range of AC Servo series motors such as the Fanuc Alpha series motors.

The Alpha series motors are high-quality AC servo motors that offer many features. These servo motors boast smooth rotation due to a special magnetic pole shape which minimizes torque ripples. A unique rotor shape allows for smaller and lighter motors that still deliver excellent acceleration. Finally, the Fanuc Alpha series is highly reliable due to their totally-enclosed, friction-free brushless design. There are 6 sub-series within the Alpha series; Alpha, AlphaM, AlphaC, Alpha (HV), AlphaM (HV) and AlphaL.

When assessing the functionality of a drive, our repair team conducts a four-step evaluation:

    1. Visual Overview
    2. Static Test
    3. Checks Under Power
    4. Alarm Codes Verification

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 Process for Fanuc Alpha Series Servo Motor

Visual Overview

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

Multimeter Positive Lead U
Multimeter Negative Lead V
Resistance Check Approximately 0.3 to 10 Ohms
Multimeter Positive Lead U
Multimeter Negative Lead W
Resistance Check Approximately 0.3 to 10 Ohms
Multimeter Positive Lead V
Multimeter Negative Lead W
Resistance Check Approximately 0.3 to 10 Ohms

Reading should be balanced across all three phases.

Mega Ohm Testing

Mega Ohm Meter Negative Lead Ground
Mega Ohm Meter Positive Lead U V W
Insulation Check Must be above 300 Mega Ohms

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

Common alarms for the Fanuc Alpha Series servo drives and motors are as follows:

Alarm Code Description Checks
Al 1 Internal Cooling Fan Stopped
  • Check to see if there is any dirt or debris clogging the fan in the servo or motor fan
  • Verify the fan connectors to make sure nothing is damaged or improperly connected
Al 2 Low Voltage, Control Power
  • Check three phases input voltage to power supply module
Al 5 DC Link Undervoltage
  • With the power off and drive discharged, check to make sure DC bus bar screws are tight
  • If multiple drives have this alarm, troubleshoot the power supply unit
  • Check incoming three phases voltage to the power supply unit
  • Verify DC bus voltage is in proper range
Alarms
8
9
A
b
C
d
E
Abnormal Current Alarm:
8 - L Axis
9 - M Axis
A - N Axis
b - L&M Axes
C - M&N Axes
d - L&N Axes
E - L, M, & N Axes
  • Disconnect motor leads from amp
  • Meg the motor
  • Check resistance phase to phase to motor (U, V, W)
  • Check amp output legs to ground for any shorts
Alarms
8
9
A
b
C
d
E
IPM Alarm:
8 - L Axis
9 - M Axis
A - N Axis
b - L&M Axes
C - M&N Axes
d - L&N Axes
E - L, M, & N Axes
  • Disconnect motor leads from servo and release the servo from EMG stop
  • If alarm goes away, check the insulation of the motor leads with a megger
  • If possible, swap drives or axes and see if alarm follows drive

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

Precision Zone Repair Benefits for Fanuc Alpha Series AC Servo Motors

    1. FREE evaluation by expert technician includes:
    • Visual Inspection
    • Static Check
    • Power Tests
    2. FREE job estimate
    3. 12 month warranty on our parts and labor
    4. Flat Price
    5. Exchange Option
    6. Rush Service

Contact Us To Start Your Repair Today!


Recently Repaired Products

Fanuc A06B-0373-B175 image A06B-0373-B175 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Recommend Refurbishing/Reconditioning
Part Group: A06B
Model: Alpha 2/3000
Shaft and Brake Specification: Taper shaft with brake (2 N-m)
Feedback Detector: A64 (absolute)
Modification 1: None
Modification 2: None

Fanuc A06B-0373-B089 image A06B-0373-B089 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Full of Oil Inside, Recommend Refurbishing/Reconditioning
Part Group: A06B
Model: Alpha 2/3000
Shaft and Brake Specification: Taper shaft (standard)
Feedback Detector: A1000 + Super Capacitor (absolute)
Modification 1: None
Modification 2: None

Fanuc A06B-0371-B175 image A06B-0371-B175 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Recommend Refurbishing/Reconditioning
Part Group: A06B
Model: Alpha 1/3000
Shaft and Brake Specification: Taper shaft with brake (2 N-m)
Feedback Detector: A64 (absolute)
Modification 1: None
Modification 2: None

Fanuc A06B-0373-B077 image A06B-0373-B077 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Bad DE Bearing, Bad ODE Bearing, Recommend Refurbishing/Reconditioning
Part Group: A06B
Model: Alpha 2/3000
Shaft and Brake Specification: Taper shaft (standard)
Feedback Detector: I64 (incremental)
Modification 1: None
Modification 2: None

Fanuc A06B-0371-B077 image A06B-0371-B077 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Recommend Refurbishing/Reconditioning
Part Group: A06B
Model: Alpha 1/3000
Shaft and Brake Specification: Taper shaft (standard)
Feedback Detector: I64 (incremental)
Modification 1: None
Modification 2: None

Fanuc A06B-0373-B176-7075 image A06B-0373-B176-7075 is an
Motors-AC Servo manufactured by Fanuc
Discovered issues: Bad DE Bearing, Bad Encoder, Bad ODE Bearing
Part Group: A06B
Model: Alpha 2/3000
Shaft and Brake Specification: Taper shaft with brake (2 N-m)
Feedback Detector: A64 + Super Capacitor (absolute)
Modification 1: #7*** GE Fanuc Nameplate
Modification 2: IP67