FANUC α i series motors and amplifiers maintenance instructions

Product model and core specifications

（1） Summary of Core Product Models

Power module (PS/PSR)

Power regeneration type (PS): 200VAC input (α iPS 5.5~55), 400VAC input (α iPS 11HV~100HV);

Resistive Regenerative Type (PSR): 200VAC input (α iPSR 3, α iPSR 5.5), only supports low-power regeneration.

Servo amplifier (SV)

200VAC input: single axis (α iSV 4~360), dual axis (α iSV 4/4~160/160), three-axis (α iSV 4/4~20/20/40);

400VAC input: single axis (α iSV 10HV~540HV), dual axis (α iSV 10/10HV~80/80HV);

Key parameters: Maximum current of 10A~540A, supporting 1-3 MPG interfaces (some models).

Spindle amplifier (SP)

200VAC input: α iSP 2.2~55, α Ci series (SPMC-2.2i~22i);

400VAC input: α iSP 5.5HV~100HV;

Special models: Supports torque series connection and dual feedback safety function (some models).

motor

Servo motor: α is/α i series (with cooling fan/liquid cooling, compatible with α iSV amplifier);

Spindle motor: α i series (with pulse encoder, supporting rigid tapping, Cs axis control).

（2） Power supply and interface specifications

Power supply voltage: 200VAC ± 15% (control circuit), 400VAC ± 10% (main circuit of high-voltage model), frequency 50/60Hz ± 1Hz;

Communication interfaces: I/O Link bus, FSSB communication (COP10A/COP10B), serial communication (CNC amplifier);

Sensor interface: Supports alpha iM/alpha iMZ/alpha iBZ sensors, analog alpha iCZ sensors, and absolute pulse encoders.

Startup and operation process

（1） Preparation before startup

Power check: Measure the input voltage to ensure capacity matching (such as the main circuit capacity of 9kVA for α iPS 5.5);

Wiring confirmation: The protective grounding connection is correct, and the phase sequence of the fan motor power supply is correct;

Component inspection: The amplifier and motor are securely fixed, and the cables are not damaged/loose.

（2） Startup and parameter initialization

Power supply startup: First connect the control power supply, release the emergency stop, and then confirm that the magnetic contactor is engaged;

Parameter settings:

Servo parameters: refer to the FANUC AC SERVO MOTOR α i series parameter manual (B-65270EN);

Spindle parameters: refer to the FANUC AC SPINDLE MOTOR α i series parameter manual (B-65280EN);

Operation confirmation:

Power amplifier: Status LED displays “Ready” (main circuit power supply is normal);

Servo amplifier: VRDY signal is normal, and the motor has no abnormal vibration/noise;

Spindle amplifier: The motor speed is consistent with the command value, and the load current is within the rated range.

（3） Data observation tool

SERVO GUIDE: Supports observing motor speed, current, torque commands, and other data, compatible with Series 30i/16i/18i/21i/0i;

Spindle Inspection Board (A06B-6078-H001): Observe internal data (such as U-phase current, motor speed), check parameter values, and output analog voltage (-5~+5V);

Servo inspection needle board (A06B-6071-K290): detects power input current (IR/IS phase).

Fault diagnosis system

（1） Alarm classification and core code

Power module alarm (α iPS/α iPSR) | Alarm code | Meaning | Key troubleshooting points|

|1 | Input circuit overcurrent | Check power phase sequence and AC reactor specifications|

|2 | Control circuit fan stop | Replace fan motor, clean heat dissipation channel|

|4 | DC Link Undervoltage | Check Input Voltage and Pre Charging Resistance|

|7 | DC link overvoltage | Check the regenerative power and power output impedance|

|E | Input power phase loss | Measure three-phase voltage and check wiring|

Servo amplifier alarm

Common codes: SV0361 (pulse encoder phase error), SV0430 (servo motor overheating), SV0654 (DB relay error);

Troubleshooting logic: First check the status of the STAT3 LED → confirm cable connection → verify parameters → detect sensor signals.

Spindle amplifier alarm

Common codes: SP0001 (motor overheating), SP0002 (excessive speed deviation), SP0027 (position encoder disconnected);

Troubleshooting logic: Distinguish between “startup alarm” (parameter/wiring issues) and “running alarm” (load/heat dissipation issues).

（2） Typical fault handling

Overheating fault (motor/amplifier): Clean the heat sink, check the cooling fan, reduce the load or acceleration/deceleration frequency;

Communication error: Check CXA2A/B interface cable, confirm amplifier ID matching, eliminate electromagnetic interference;

Sensor malfunction: detect feedback signal waveform (such as α iM sensor Vpp=0.5~1.2Vp-p), check cable shielding layer.

Component replacement and preventive maintenance

（1） Replacement process of vulnerable parts

Fan motor replacement

Applicable models: Internal cooling fan (A90L-0001-0510/0511), radiator cooling fan (A90L-0001-0509);

Operation steps: Power off and discharge → Loosen the fixing screw → Remove the connector → Install a new fan (pay attention to the wind direction).

Absolute pulse encoder battery replacement

Attention: It must be replaced with the power on to avoid absolute position data loss;

Replacement object: Independent battery box, servo amplifier built-in battery.

Fuse replacement

Location: Power module (F1/F2), servo/spindle amplifier control board;

Requirement: Use fuses of the same specifications and confirm the cause of the short circuit before replacement.

（2） Preventive maintenance

Regular inspection:

Insulation resistance: measured with a 500VDC insulation resistance meter, it is better to have a resistance of ≥ 100M Ω, and if it is ＜ 1M Ω, the motor needs to be replaced;

Cooling system: Clean the cooling fins monthly to avoid chip/oil mist accumulation;

Cable inspection: Check the shielding layer and connector contact of the cable every quarter.

Storage requirements: When storing the motor, the shaft should be placed horizontally and the terminal box should face upwards; The amplifier should avoid contact with corrosive gases/water droplets.

Periodic maintenance: Refer to the FANUC SERVO AMPLIFIER α i series manual (B-65282EN) for annual maintenance.