Fanuc A06B-0123-B075 AC Servo Motor
Alpha 3/3000, Taper Shaft, A64 Encoder, No Brake
Product Overview
Part Number: A06B-0123-B075
Also Searched As: A06B0123B075, FANUC A06B-0123-B075, Fanuc Alpha 3/3000
Motor Model: α 3/3000
Series: Fanuc Original Alpha Series
Classification: Fanuc Alpha Series AC Brushless Servo Motor -- 3 Nm Stall Torque, 0.9 kW, 3,000 rpm, Taper Shaft, No Brake, A64 Incremental Encoder, IP65
Technical Specifications
| Parameter |
Value |
| Part Number |
A06B-0123-B075 |
| Motor Model |
α 3/3000 |
| Rated Output |
0.9 kW |
| Stall Torque |
3 Nm |
| Stall Current |
4.6 A |
| Rated Speed |
3,000 rpm |
| Motor Input Voltage |
127V (3-phase) |
| Encoder |
Alpha A64 (incremental, 64,000 ppr) |
| Shaft Type |
Taper with key |
| Electromagnetic Brake |
None |
| Protection Rating |
IP65 |
| Compatible Amplifiers |
Fanuc original alpha series SVU amplifiers |
| Compatible Controls |
Fanuc Series 0, 15, 16, 18 (original alpha generation) |
| Origin |
Japan |
Alpha 3/3000 in the Alpha Family
The Fanuc original alpha series powered CNC machine tools through the 1990s and 2000s, with many machines still in production today. The A06B-0123-B075 provides a like-for-like replacement solution when these motors fail.
With 3 Nm stall torque and 0.9 kW output, the α 3/3000 occupies the compact tier of the original alpha range, making it ideal for lighter feed axes on small to mid-size CNC machine tools. Applications include X and Z drives on compact lathes, auxiliary axes on machining centers, and secondary positioning mechanisms.
The 3,000 rpm rated speed combined with a 5mm pitch ball screw delivers 15 m/min rapid traverse performance. The 127V motor input voltage at 4.6A stall current confirms compatibility with original alpha SVU amplifiers.
Taper Shaft Design
The precision-ground taper shaft with key provides self-centering coupling that ensures repeatable positioning. The conical geometry automatically registers the hub concentrically during installation, while the key provides positive torque transmission.
Installation Note: Always use a proper gear puller applied at the hub face during removal. Never use wedges or impact against the hub body. Inspect taper and bore surfaces before reinstalling on the new motor.
A64 Incremental Encoder Compatibility
The Alpha A64 encoder delivers 64,000 counts per revolution through the parallel incremental encoder interface. Key operational considerations:
- Homing required on every power-up: The A64 does not retain position through power-off
- Generation-specific compatibility: Incompatible with αi series amplifiers that require serial encoder protocol
- Requires original Fanuc alpha SVU amplifier for proper operation
At 64,000 ppr on a 5mm pitch ball screw, position loop resolution is approximately 78 nm per count.
No Brake Configuration
The B075 designation confirms no electromagnetic brake. Axis position at rest is maintained by the alpha SVU amplifier's servo lock, which is adequate for horizontal axes without gravitational load components.
Important: For vertical axes or inclined feeds requiring mechanical holding, use the braked variant A06B-0123-B175. The B075 is not a safe substitution on gravity-loaded axes.
A06B-0123 Series Configuration Reference
| Part Number |
Shaft |
Brake |
Encoder |
| A06B-0123-B075 |
Taper |
None |
A64 incremental |
| A06B-0123-B175 |
Taper |
Yes (brake) |
A64 incremental |
| A06B-0123-B075#7076 |
Taper |
None |
A64 (IP67) |
All variants share the α 3/3000 motor body specifications. Match replacement configuration exactly to the original.
Amplifier and CNC Compatibility
Requires a Fanuc original alpha SVU amplifier. Compatible CNC platforms include Fanuc Series 0, 15, 16, and 18 on the original alpha generation. Not compatible with αi series amplifiers or β series drives.
After installation, verify axis parameters (motor type code, current limit, maximum speed) are correctly set for the α 3/3000 specification.
Typical Applications
- CNC lathe X and Z feed axes - Primary carriage and cross-slide drives on compact CNC turning centers
- Small machining center feed axes - X, Y, and Z drives on compact vertical machining centers
- Secondary and auxiliary axes - Additional positioning drives on multi-axis machines and rotary tables
Frequently Asked Questions
Is this motor compatible with Fanuc αiSV amplifiers?
No. The A64 uses the parallel encoder interface of the original alpha platform, which is electrically incompatible with αiSV amplifiers that require serial encoder protocol. This motor must be paired with an original Fanuc alpha SVU amplifier.
Why does the axis home every time the CNC powers up?
The A64 is an incremental encoder with no power-off position retention. A reference-return traverse is required on every power-up to establish the machine coordinate, which is normal behavior for all original alpha series equipment.
Can the B075 (no brake) replace a B175 (braked) motor?
Only on confirmed horizontal axes with no gravitational load component. The B175 brake is a safety mechanism for vertical and inclined axes. Servo lock alone cannot hold an axis under gravity when the amplifier is de-energized.
How is the taper shaft hub correctly removed during motor replacement?
Use a gear puller applied at the hub face, reacting against the shaft end. Never use wedges, chisels, or impact against the hub body. After removal, inspect both the taper and hub bore surfaces before reinstallation.
Is the A06B-0123-B075 repairable, or replacement only?
Fully repairable. Qualified repair facilities address all common failure modes including bearing replacement, A64 encoder replacement, stator winding repair, and seal replacement. For facilities managing multiple machines, maintaining a tested exchange unit minimizes downtime.
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