FANUC A06B-0162-B175#0006 — Alpha Series αM6/3000 AC Servo Motor, Taper Shaft, Brake, αA64 Absolute Pulsecoder, Flying Leads

Quick Reference

Part Number: A06B-0162-B175#0006 (also referenced as A06B0162B175#0006)

Motor Model: FANUC αM6/3000 — Alpha series, M sub-family

Key Configuration: Taper shaft · 24V DC holding brake · αA64 absolute encoder · Flying leads cable termination

Product Overview

The FANUC A06B-0162-B175#0006 is a 1.4 kW AC servo motor from FANUC's first-generation Alpha (α) series, specifically the αM sub-series — the medium-frame compact group developed for CNC machine tool feed-axis applications. At its most fundamental level, this is an αM6/3000 motor body equipped with three features that together define the complete part number: a taper output shaft, an electrically released 24V DC holding brake, and a factory cable configuration using flying leads (bare wire ends without a pre-fitted moulded connector). That last detail is what separates the #0006 from otherwise identical B175 variants and makes this motor the preferred choice in OEM machine builds and custom cable harness installations where the integrator terminates the wiring directly into their own connector housings or junction boxes.

This motor is an established component of the FANUC Alpha feed-axis ecosystem, fully compatible with the Alpha SVM and SVU series servo amplifiers, and widely used across CNC machining centres, turning centres, and general-purpose servo drive applications. Like all αM6/3000 motors, it operates at 3,000 rpm rated speed with 6 Nm rated torque and returns absolute encoder position data through an αA64 pulsecoder at 64,000 counts per revolution.

Verified Specifications

The Taper Shaft: Design Intent and Practical Implications

The αM6/3000 motor platform was designed with the taper shaft as the standard output shaft configuration. This is not an alternative option added later — the taper is the intended coupling interface for this motor family. FANUC's own engineering documentation recommends the taper shaft wherever machine design and delivery timelines permit, and the reason is straightforward: a properly fitted taper coupling provides a self-centering, zero-backlash connection that distributes the engagement load over a larger contact area than a keyed parallel shaft, and it can be reliably removed and refitted without mechanical damage to either the shaft or the coupling bore.

On a machine tool feed axis, these properties matter. The coupling between a servo motor and the ballscrew — whether through a flexible coupling, a rigid coupling, or a timing belt pulley — must maintain consistent alignment and transmit torque without slip or fretting. Taper connections, once drawn up correctly with the appropriate installation torque, do not slip. Removal is clean and does not disturb the shaft surface finish in the way that pressing or driving off a straight-bore coupling sometimes does.

For the A06B-0162-B175#0006 specifically, the taper dimensions follow the FANUC standard for the αM6 frame. Any replacement coupling, pulley, or gear being fitted must match this taper specification exactly — not a parallel-bore part with an adapter sleeve, but a correctly dimensioned taper bore component made for this motor family.

Holding Brake: How It Functions and When It Matters

The brake fitted to the A06B-0162-B175#0006 is a spring-applied, electrically released holding brake powered by 24V DC. Understanding the operational logic is critical for both installation and troubleshooting: the brake is engaged when the 24V supply is absent (spring force clamps the rotor) and released when 24V is applied (electromagnet overcomes the spring). This fail-safe design means power loss — whether planned or unplanned — automatically applies the brake. On a vertical axis, this prevents the driven load from falling under gravity when the servo drive is de-energised or in an E-stop state.

The standard brake on B175-series motors is rated for 2 Nm holding torque — a static retention force, not a dynamic stopping brake. Its purpose is to hold the axis position when the drive is off, not to decelerate a rotating load. Using it as a dynamic brake will rapidly degrade the friction surfaces and cause premature brake failure. In the correct application, the drive decelerates the motor under controlled servo power first; the brake only engages once the axis has stopped.

Brake release timing matters in commissioning. The 24V supply to the brake must be applied (and verified) before the servo drive attempts to move the axis. A common commissioning error is inadequate 24V supply capacity or excessive cable resistance to the brake coil, which results in a weaker-than-specified magnetic field, incomplete release, and intermittent drag or heating of the brake assembly. A surge absorber (snubber diode or RC circuit) should always be fitted at the brake coil connection in the power magnetics cabinet to suppress the voltage spike generated at de-energisation.

Flying Leads: What the #0006 Suffix Means in Practice

The suffix #0006 on this motor specifies flying leads — the power cable, feedback cable, and brake cable all exit the motor body with bare wire ends. No moulded connector housing, no pre-assembled plug, no backshell. The cables simply terminate with stripped conductors ready for the integrator to connect.

This is a deliberate ordering choice, not a cost-reduction measure. Flying leads are specified in situations where:

• The machine OEM assembles their own cable harness with standardised in-house connector types that differ from FANUC's standard circular plugs
• The motor is being installed into a cable chain or duct where a pre-assembled connector would not pass through the conduit without being removed anyway
• The installation uses terminal block wiring within an enclosure, making direct wire termination neater than adding a mating connector
• The cable assembly is done by a specialist cable supplier who terminates to their own quality and specification

For end-users purchasing this motor as a direct replacement, the flying leads requirement must be understood before ordering. If the machine in the field has cables with moulded FANUC standard connectors, a #0006 motor cannot be plugged in directly — either the existing machine cables must be re-terminated to match, or the correct connector-equipped variant (typically no suffix, or #0000) must be ordered instead. Substituting a flying-leads motor without accounting for this will leave the machine unable to connect the replacement until additional cable work is completed.

αA64 Absolute Pulsecoder: Encoder Architecture and Battery Backup

The A06B-0162-B175#0006 uses the αA64 serial absolute pulsecoder, an optical encoder integrated into the rear cap of the motor. Its 64,000 counts-per-revolution resolution feeds high-precision position data back to the servo amplifier through a serial communication link rather than the parallel A/B/Z quadrature lines used in older encoder technologies.

Position retention in absolute mode depends on a lithium backup battery housed in the servo amplifier, not in the motor body. This is an important service detail. The battery maintains the multi-turn position counter while the machine is powered down; when power is restored, the CNC can read back the absolute axis position without requiring a reference return run. However, if the battery fails or is allowed to discharge fully, the position data is lost and a reference return must be performed before the machine can resume normal operation.

FANUC alarm codes SV5136 (battery voltage low) and SV5137 (battery voltage zero / position data lost) are the diagnostic indicators for this condition. SV5136 provides an advance warning period — the position data is still intact but battery replacement should be scheduled promptly. SV5137 means the data is gone; after battery replacement, a full reference-return cycle is mandatory. Planned battery replacement at regular service intervals (typically every two to three years in normal production service) prevents unplanned interruptions from encoder battery loss.

Compatible Servo Amplifiers

The A06B-0162-B175#0006 is mechanically and electrically interchangeable with all other A06B-0162-B*** variants for amplifier selection purposes. The motor model is αM6/3000, requiring an 80A-rated servo amplifier channel.

On dual-axis modules, the αM6/3000 must occupy the M-axis channel (80A rating). The L-channel on SVM2-40/80 is rated for 40A only and cannot drive this motor.

A06B-0162-B175 Variant Reference Table

All variants listed: αM6/3000, 1.4 kW, 6 Nm, 3,000 rpm, 144 V, 200 Hz, 6 A.

FAQ

Q1: What is the practical difference between the A06B-0162-B175#0006 and the A06B-0162-B175 without a suffix, and does it matter for a field replacement?

The only difference is the cable termination. The base A06B-0162-B175 (no suffix) ships with the standard FANUC moulded connector on the power cable and brake cable, allowing direct plug-in to the existing machine wiring. The #0006 variant ships with the same cables terminated as bare flying leads — stripped wire ends with no connector housing fitted. The motor body, windings, taper shaft, brake, and αA64 encoder are physically identical. In a field replacement scenario, this distinction is critical: if the machine uses standard FANUC connectors and the replacement motor has flying leads, additional wiring work is required before the motor can be connected. If the replacement motor is the connector-equipped version and the machine was originally wired to flying leads, the connector on the motor may not match the field-fitted termination. Always confirm the cable termination style against the machine's connection scheme before ordering; ordering the wrong termination adds downtime that could have been avoided.

Q2: The machine's vertical axis uses this motor — what checks are needed after replacement to confirm the brake is working correctly?

After installing the replacement motor and before releasing the axis for normal production, three checks should be performed on the brake system. First, verify that the 24V DC supply to the brake coil is at the correct voltage and that the wiring continuity is intact through the new flying leads termination — any connection error in the flying leads will prevent the brake from releasing correctly. Second, with the servo drive enabled and the axis held by the drive, command the 24V supply off and verify that the axis does not drift under the load of the vertical slide — this confirms the brake is holding. Third, with the drive enabled and the 24V brake supply on (brake released), verify that the axis moves freely with no drag or abnormal resistance — this confirms the brake has fully released and is not dragging on the rotor. Partial release due to insufficient 24V supply voltage or high resistance in the brake coil wiring is a common post-installation issue that shows up as axis following error or elevated motor temperature during normal operation.

Q3: After replacing this motor, the CNC displays a pulsecoder alarm and will not allow reference return. What is likely to have caused this and how is it resolved?

The most common cause is that the absolute position data was lost from the αA64 encoder during the swap. This happens when the replacement motor is connected without a charged battery in the servo amplifier, or when the amplifier battery was already near end-of-life and the power interruption during motor exchange completed the discharge. Without battery-backed memory, the new encoder has no stored position data and the CNC detects this as a pulsecoder fault — typically alarm SV5137 or equivalent. The resolution is straightforward: confirm the amplifier battery is replaced with a fresh unit, cycle power to let the new battery stabilise, then perform a full reference-return (zero point return) on the affected axis. Once the reference is established, the CNC stores the absolute offset for the new encoder and the axis will operate normally on subsequent power cycles without requiring a repeated reference return. If SV5136 (battery low) rather than SV5137 appears, the position data is likely still intact — replace the battery promptly and the reference return may not be required.

Q4: Is the taper shaft on this motor the same specification as the taper shafts used on the straight-shaft αM6 variants with a taper adapter, and can couplings be interchanged?

No. The taper shaft on the A06B-0162-B175 is an integral, machined taper on the motor's output shaft — the taper geometry is built into the shaft itself. Straight-shaft motor variants (B575, B775 series) do not have this taper and cannot be fitted with an adapter to create an equivalent taper interface. Conversely, a coupling, pulley, or gear with a taper bore machined to the αM6 taper specification will fit only the taper-shaft motor variants. If a machine was designed around the taper shaft configuration, a straight-shaft replacement motor cannot be used without also replacing the coupling component on the mechanical side. When sourcing a replacement, always match the shaft type as well as the motor model number. The taper shaft in the αM6 family also has a specific key or keyless designation depending on the motor variant; for the B175, the taper shaft is the standard version without a separate keyway.

Q5: This motor is listed as discontinued. What options are available for a modern equivalent, and is a cross-series substitution straightforward?

The FANUC Alpha series, including the A06B-0162-B175#0006, has been discontinued as a current production item. However, two realistic procurement paths remain. The first is sourcing NOS (new-old-stock) or professionally refurbished units through specialist FANUC parts suppliers and servo motor repair facilities — this is a like-for-like replacement that requires no changes to the machine, amplifier, or CNC parameters. The second is upgrading to the current FANUC αi series, where the functional equivalent class would be found in the αiF 8/3000 or similar αiF family motors with a taper shaft and brake option. An αi series motor replacement is not plug-and-play: it requires an αi series servo amplifier (if not already installed), new-generation feedback cables, updated CNC parameters for the new motor ID, and confirmation that the taper shaft dimensions and brake voltage match the machine's mechanical and electrical design. For machines with a long remaining service life where parts availability is the main concern, a full drive upgrade to the αi platform makes sense as a planned project. For machines nearing end-of-life or where the disruption of an αi upgrade is not justified, like-for-like refurbished replacement remains the most practical option.