Fanuc A06B-0143-B177 | ALPHA Series AC12/3000 Servo Motor with Brake & I64 Encoder
Part Number: A06B-0143-B177
Series: ALPHA AC Servo Motor
Model: AC12 / 3000
Condition: New / Refurbished / Exchange Available
Overview
The Fanuc A06B-0143-B177 is an ALPHA series AC servo motor rated for 3,000 RPM maximum speed — the higher-speed sibling within the AC12 motor family. It is purpose-built for CNC axis drive applications where a combination of holding brake, high-resolution feedback, and reliable continuous torque is essential. The motor features an integrated electromagnetic brake and an I64 series encoder, making it ideal for vertical axes, rotary tables, and any application requiring secure load holding during rest or emergency stop events.
This motor was commonly used on small to medium CNC machine tools, including vertical machining centers, turning centers, and multi-axis platforms with Fanuc servo drive systems. The AC12 designation indicates the motor's 12 Nm torque class, and the 3,000 RPM capability provides faster traverse rates compared to 2,000 RPM AC12 variants.
Key Specifications
| Motor Series |
ALPHA AC Servo |
| Model Designation |
AC12 / 3000 |
| Maximum Speed |
3,000 RPM |
| Torque Class |
12 Nm |
| Shaft Configuration |
Straight Shaft |
| Brake |
Integrated Electromagnetic Brake |
| Feedback Device |
I64 Encoder |
| Application |
CNC Axis Drive |
| Ingress Protection |
ALPHA Series Standard |
Design & Construction
The straight shaft design ensures clean mechanical integration with standard coupling hubs, bellows couplings, and ballscrew drive arrangements used across Fanuc-compatible machine tool platforms. The shaft dimensions follow ALPHA series standards for the AC12 frame, simplifying direct replacement on existing machines.
The integrated electromagnetic brake features a spring-applied, electrically released design — engaging automatically when power is removed and releasing when the brake circuit is energized. This fail-safe mechanism prevents axis drop during power loss or emergency stops, protecting both workpiece and machine structure.
Operating at up to 3,000 RPM, this motor delivers faster traverse capability than 2,000 RPM AC12 variants, reducing non-cutting time on machines with longer axis travels. The torque characteristics are optimized for typical inertia loads in ballscrew-driven CNC axes at this power class.
I64 Encoder & Feedback
The I64 high-resolution incremental encoder integrated into the motor housing provides position and velocity feedback signals for closed-loop axis control. Its pulse resolution supports fine interpolation required for precision contouring, profiling, circular interpolation, and tight-tolerance positioning work.
When replacing an A06B-0143-B177, ensure the replacement unit carries the same I64 encoder specification. Substituting a motor with a different encoder type may require servo amplifier parameter changes and could affect axis accuracy or trigger encoder mismatch alarms.
Drive & Control Compatibility
Compatible with Fanuc ALPHA series servo amplifiers (SVM and SVU modules) and Fanuc CNC control platforms including Series 0, 0i, 16, 18, 21, and related generations. The brake circuit requires a dedicated 24 VDC power supply and must be properly interlocked with the servo ready signal to ensure brake release before axis movement.
For retrofitting or rebuilding applications, verify the servo drive's motor parameter group (motor type code, encoder type, and maximum speed) matches the A06B-0143-B177 specification before power-up. Incorrect parameter selection can cause instability, velocity loop oscillation, or drive alarms.
Sourcing & Condition Notes
The A06B-0143-B177 remains actively traded in MRO and surplus servo motor markets. When evaluating used or refurbished units:
- Check brake release voltage and confirm clean, full disengagement
- Inspect encoder connector for corrosion or damaged pins
- Verify shaft runout and bearing condition
- Bench-test for brake torque, winding insulation resistance, and encoder output integrity
Frequently Asked Questions
Why does this motor have a brake, and how does it work?
The A06B-0143-B177 uses a spring-applied, electrically released electromagnetic brake. When de-energized (power-down, E-stop, or servo alarm), the spring automatically engages the brake to hold the axis position. It releases when 24 VDC is applied to the brake coil before axis command. This fail-safe design is standard for vertical axes and loads requiring mechanical holding.
What CNC systems and drives are compatible with this motor?
Compatible with Fanuc ALPHA series servo amplifiers (SVM/SVU) and Fanuc CNC controls including Series 0, 0i, 16, 18, and 21. The servo drive must be parameterized with the correct motor type code for AC12/3000 with I64 encoder. Incorrect configuration commonly causes axis instability or drive faults.
What is the I64 encoder, and can it be replaced separately?
The I64 is a high-resolution incremental encoder mounted to the motor rear, providing position and speed feedback for closed-loop servo control. While technically replaceable by qualified service facilities, encoder failure often indicates broader damage, warranting full motor evaluation before reinstallation.
What is the difference between AC12/3000 and AC12/2000 variants?
Both share the 12 Nm torque class but differ in maximum speed — 3,000 RPM versus 2,000 RPM. The AC12/3000 delivers faster traverse rates for longer axis travel or higher rapid feed requirements. Electrical ratings and drive parameters differ, preventing direct interchange without servo amplifier reconfiguration.
How should I test a used A06B-0143-B177 before installation?
Verify balanced three-phase winding resistance across all phases. Check winding insulation resistance to earth (should exceed 1 MΩ). Apply 24 VDC to brake circuit and confirm free shaft rotation, then de-energize to verify brake locking without creep. Check for bearing roughness or noise during manual rotation. Confirm clean quadrature signals from I64 encoder using servo test equipment.
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