Fanuc A06B-0373-B575#7008 — Alpha A2/3000 AC Servo Motor, Keyed Shaft, IP67 Sealed, A64 Encoder

Product Overview

Part Number: A06B-0373-B575#7008

Also Searched As: A06B0373B575, FANUC A06B-0373-B575#7008, A06B-0373-B575 7008

Alternate Part: A06B-0373-B575#0008

Motor Model: Alpha A2/3000 (1-OSP/3000)

Classification: Fanuc Original Alpha Series AC Brushless Servo Motor — 2 Nm Stall Torque, 3,000 rpm, Straight Shaft with Keyway, No Brake, A64 Incremental Encoder, IP67 Sealed

Technical Specifications

Where This Motor Fits — The Original Alpha Generation

The A06B-0373-B575#7008 is a Fanuc original Alpha series motor — not αiS, not αiF, not αi anything. It belongs to the first generation of Fanuc alpha motors that powered a large population of CNC machine tools throughout the 1990s and well into the 2000s. Understanding this generational distinction is not academic — it is operationally essential. The original alpha motor series and the later αi generation use different encoder protocols, different amplifier interfaces, and different parameter sets. They are not cross-compatible without a system-level upgrade.

For facilities maintaining machines controlled by Fanuc Series 0, 15, 16, or 18 CNC with original alpha SVU amplifiers, the A06B-0373-B575#7008 is simply the correct motor. There is no modern αi drop-in replacement that installs straight into the existing drive system without converting the amplifier at the same time. When this motor fails, the like-for-like replacement is another A06B-0373 series alpha motor — this part.

The A2/3000 designation places this motor in the compact lower end of the original alpha servo range. Two Newton-metres of stall torque and 3,000 rpm maximum speed describe a small, fast motor built for light positioning axes on compact machine tools, subsidiary drives on multi-axis equipment, and Fanuc robot joint applications where a small motor envelope and reliable closed-loop positioning are the governing requirements.

#7008 Suffix — IP67 Sealed with Keyway: The Critical Configuration Details

The suffix in a Fanuc motor part number is not a revision code or a batch identifier. It encodes specific physical and configuration details that make the motor either correct or incorrect for the machine it was designed for. The #7008 on this motor communicates two definitive facts:

The shaft has a keyway. The straight shaft is machined with a keyway for positive mechanical key engagement between the motor shaft and the coupling hub. At 2 Nm stall torque, the key transmits torque through shear engagement rather than relying solely on friction clamping — important on axes that reverse frequently and where vibration could cause a friction-only coupling to work loose over service time. The coupling hub on the machine must be a keyed bore to match. A hub bored without a keyway cannot correctly engage a keyed shaft — the keyway depth prevents proper bore-to-shaft contact on the non-keyed side.

IP67 sealing is standard on this unit. The #7076 and #7008 suffix variants in the B575 series carry IP67 protection — immersion-rated sealing that withstands temporary submersion to one metre depth for up to thirty minutes. In machine tool environments, IP67 means the motor survives direct coolant flood, high-pressure coolant jet impingement, and coolant pooling in the motor mounting area without compromising the winding insulation or encoder internals. The standard #7000 base variant carries IP67 as well per the A2/3000 specification at this suffix level — verified across multiple supplier records showing the 10 lb (~4.5 kg) frame as standard sealed construction.

The practical message: if the machine's failed motor was a #7008, the replacement must also be a #7008 — not because the suffix represents performance data, but because it confirms the shaft geometry matches the existing coupling hub and the sealing level matches the machine's coolant environment.

A64 Incremental Encoder: Compatibility and Operating Requirements

The A64 fitted to the A06B-0373-B575#7008 is a parallel incremental encoder delivering 64,000 counts per revolution. It is the standard feedback device for the original Fanuc alpha motor series and is specifically matched to the original alpha SVU amplifier's encoder interface.

Three operational and compatibility points matter here:

Every power-up requires a reference-return (homing) traverse. The A64 is an incremental encoder — it does not retain shaft position through power interruptions. When the CNC system powers on, every axis fitted with an A64 encoder motor has no position data until it executes a homing cycle to find its reference marker. On compact machine tools with short axis travels, this cycle takes seconds. The machine's startup sequence accounts for it automatically. It is not a fault; it is normal incremental encoder behaviour.

The A64 is incompatible with αi series amplifiers. The A64 uses the parallel encoder signal interface of the original alpha platform. Fanuc αi amplifiers (αiSV) expect the serial encoder protocol of αiS and αiF motors. These two interfaces are electrically and logically different at the connector and protocol level. There is no parameter setting that makes an αiSV amplifier read an A64 encoder correctly. The A06B-0373-B575#7008 must be driven by an original Fanuc alpha SVU amplifier to function.

64,000 ppr provides adequate resolution for this motor's applications. At 64,000 counts per revolution on a 5mm pitch ball screw in direct coupling, the position loop closes at approximately 78 nanometre resolution per count. For the compact positioning axes and robot joints this motor serves, this feedback quality supports the positioning accuracy these applications require.

Straight Keyed Shaft and IP67: A Combination That Matters on Machine Tool Axes

The combination of a keyed straight shaft and IP67 sealing in a single 4.5 kg motor body reflects a straightforward design logic for machine tool servo applications.

The straight-plus-key shaft is the coupling interface for machines where the driven component — a pulley, a coupling flange, a gear hub — has a keyed bore. The key ensures positive torque transmission under reversing load and vibration without the risk of coupling slip that a purely friction-clamped smooth shaft can develop over service time. At 2 Nm, the mechanical stress on the key is modest — the keyway configuration is about coupling interface compatibility and long-term security, not about transmitting torque at the material limit.

IP67 sealing is the practical choice for a motor mounted anywhere near the cutting zone of a CNC machine tool. The coolant environment in a machining centre or CNC lathe is aggressive — coolant mist, directed coolant jets, coolant accumulation in pockets and mounting areas. IP65 protects against directed water jets but not immersion. IP67 covers temporary immersion, which means it handles the pooling and flooding conditions that occur when a machine's coolant delivery is directed toward the work zone rather than carefully managed around it. For a motor mounted on a compact axis inside a machine enclosure where coolant behaviour is not always predictable, IP67 is the correct default.

No Brake: Correct for Horizontal and Symmetrically Loaded Axes

The B575 base designation confirms this motor carries no electromagnetic brake. Position at rest is maintained by the alpha SVU amplifier's servo lock — the position loop active, the A64 encoder reporting shaft position continuously, and the amplifier correcting to the commanded angle.

On horizontal axes and any axis where no net gravitational force acts along the shaft rotation direction, servo lock is entirely adequate. The axis holds commanded position reliably while the amplifier is active. No 24V brake circuit, no brake relay, no brake timing in the machine's startup and shutdown sequence.

The brake variant of the A2/3000 — the A06B-0373-B169 series — carries a spring-applied holding brake for vertical axes and inclined feeds where mechanical holding at servo-off is required. If the machine's failed motor was a B169 (brake variant), the B575 is not an appropriate replacement on a vertical or gravitationally loaded axis. Confirm the original motor's brake configuration before ordering.

A06B-0373-B575 Series Variants

All variants share the same A2/3000 motor body, stall torque, speed, and encoder. The #7008 is the IP67-sealed keyed shaft configuration — matching it exactly to the coupling hub geometry on the machine is the essential replacement step.

Amplifier and CNC Compatibility

The A06B-0373-B575#7008 requires an original Fanuc alpha series SVU amplifier — the first-generation alpha servo drive unit, not the αi generation that followed. Compatible CNC platforms include Fanuc Series 0, 15, 16, and 18 on the original alpha amplifier generation, as well as Fanuc robot controllers from the same era (R-J2, R-J3 platform equivalents).

This motor is not compatible with:

• Fanuc αiSV amplifiers (αi generation)
• Fanuc β or βi series amplifiers
• Any amplifier that requires serial encoder protocol input

When fitting this motor as a replacement, verify the amplifier is the correct original alpha SVU variant and that axis parameters — motor type code, current limit, and maximum speed — are set for the A2/3000 specification. A parameter mismatch produces unstable servo behaviour or amplifier faults even when the motor is electrically correct.

Typical Applications

Compact CNC machine tool feed axes on original alpha drive systems. X, Y, and Z drives on small-format machining centres, CNC lathes, and cylindrical grinders controlled by Fanuc Series 0 or 16 with original alpha SVU amplifiers, where the 2 Nm stall torque and 3,000 rpm ceiling match the axis load and speed requirement.

Fanuc robot joint drives on first and second generation robots. Joint axis motors on early-generation Fanuc industrial robots using the 1-OSP/3000 motor frame, where the IP67 sealing and A64 encoder reflect the original robot specification for the joint.

Auxiliary and subsidiary axes on mid-size CNC machining centres. Secondary positioning axes, rotary table drives, and B-axis mechanisms on machines where the original alpha drive system powers a mix of axis sizes, and the A2/3000 frame handles the lighter end of the axis load range.

Replacement on machines still running original alpha amplifiers. Any Fanuc-controlled machine that was built around original alpha SVU drives and carries one or more A06B-0373-B575 motors in service, where a failed unit requires a like-for-like replacement to restore production without a drive system conversion.

FAQ

Q1: Can the A06B-0373-B575#7008 be used with a modern Fanuc αiSV amplifier as a direct replacement?

No — not without converting the entire axis drive system. The A64 encoder on this motor uses the parallel incremental interface of the original alpha platform, which is electrically and logically incompatible with αiSV amplifiers. The αiSV expects serial encoder protocol from αiS/αiF motors. Substituting this motor into an αiSV amplifier without the correct motor-encoder-amplifier matching would result in encoder communication faults or complete absence of feedback. A like-for-like alpha motor replacement requires the original alpha SVU amplifier to remain in place.

Q2: The #7008 suffix — does it indicate any change to motor performance compared to the #7000 variant?

No performance change. The #7008 suffix adds a keyway to the straight shaft compared to the #7000 smooth-shaft variant. Both carry IP67 sealing, the same A64 incremental encoder, identical 2 Nm stall torque, 3,000 rpm ceiling, and no brake. The only functional difference is the shaft engagement geometry. The machine's coupling hub determines which suffix is correct — a keyed bore requires #7008; a smooth bore requires #7000.

Q3: Does this motor need a homing cycle every time the CNC powers up?

Yes. The A64 is an incremental encoder with no power-off position retention. Every CNC power-up requires the axis to execute a reference-return (homing) traverse to find its reference marker before the CNC can establish the machine coordinate and enter automatic operation. This is standard behaviour for all original alpha series motors with A64 encoders — the machine's startup sequence is already programmed to handle it. It is not a sign of a problem; it is how incremental encoder systems work.

Q4: Why is IP67 sealing significant for this specific motor in CNC machine tool use?

IP67 provides protection against temporary immersion — more robust than IP65's directed water jet protection. In a CNC machine tool environment, coolant behaviour around servo motors is often unpredictable: coolant pools in mounting recesses, concentrated jets redirect off workpieces and fixtures, and high-pressure through-coolant systems create spray patterns that reach motors well outside the immediate cutting zone. IP67 sealing ensures the motor windings and encoder remain protected even when coolant accumulates directly at the motor body. For compact axes where motor packaging puts the motor close to the coolant zone, IP67 is the correct sealing standard.

Q5: Is repair a viable option for a failed A06B-0373-B575#7008, or should it be replaced outright?

Repair is a well-established and cost-effective option for this motor. The original alpha A2/3000 frame is a mature, well-documented motor that qualified Fanuc servo motor repair facilities service routinely. Common failure modes — bearing wear, winding insulation degradation, A64 encoder failure — are all addressable through rebuild. For facilities running multiple machines with this motor type, repair combined with a core exchange programme can significantly reduce the per-motor replacement cost compared to outright new or refurbished purchases. The key requirement is using a repair facility with Fanuc alpha series experience and the ability to test the repaired motor on a compatible original alpha amplifier, not a generic servo test stand, before return.