A06B-0373-B175 Fanuc AC Servo Motor A06B0373B175 AO6B-O373-B175

FANUC A06B-0373-B175 | Alpha 2/3000 AC Servo Motor — 2 Nm / 3000 rpm / Tapered Shaft / Electromagnetic Brake

Part Number: A06B-0373-B175

Also Searched As: A06B0373B175

Manufacturer: FANUC Corporation (Japan)

Alpha Series Context

The A06B-0373-B175 is FANUC's Alpha 2/3000 servo motor — a 2 Nm, 3000 rpm motor from the red-cap Alpha series, the generation that replaced the BM and BC series on FANUC CNC machine tools from the early 1990s onwards. Alpha motors were designed for the MCC (Multi-Channel Controller) servo architecture used in FANUC's 16/18/21 and related control generations.

At 2 Nm continuous and 3000 rpm, this motor is sized for small-to-medium machine tool axes — a single-axis ATC (automatic tool changer) drive, a chip conveyor servo, a rotary table indexing axis, or a small tailstock feed — where the Alpha series' combination of absolute encoder feedback and compact frame size is the right fit.

The A64 absolute pulsecoder provides 64,000 pulses per revolution and stores absolute multi-turn position between power cycles. At power-on, the axis reports its exact position immediately — no homing cycle required. This is a practical advantage on machines with frequent power cycling or where a lost position reference would require manual recovery before production resumes.

Tapered Shaft and Brake — What the B175 Suffix Means Mechanically

The B175 suffix encodes two mechanical specifications that define how this motor integrates into a machine:

Tapered shaft with keyway: The shaft tapers toward the end and carries a machined keyway. Tapered shafts are pulled into the hub bore axially and tightened with a locking nut — a self-centering fit that handles both radial and axial loads without relying solely on friction. The keyway transmits torque. This combination is common on machine tool axes where positive mechanical engagement and accurate shaft centring both matter.

Electromagnetic brake (spring-applied): The brake is engaged by default — the spring holds the brake pads against the disc whenever the brake coil is de-energised. The coil must be energised (typically 24V DC) to release the brake for normal motor operation. This design ensures the brake is applied automatically on power loss, E-stop, or alarm condition. It is standard on vertical axes, inclined feeds, and any drive where the load has a gravitational component and uncontrolled movement at servo-off would be hazardous.

Key Specifications

FAQ

Q1: What servo amplifiers are compatible with the A06B-0373-B175?

The Alpha 2/3000 pairs with FANUC Alpha SVM (servo amplifier modules) from the A06B-6079 and A06B-6096 series. The specific SVM capacity depends on the drive system's axis configuration — A06B-6079-H201 (SVM2-12/12) and A06B-6096-H201 are typical pairings for this motor size. Confirm the amplifier's current rating covers the 2.6A motor current.

Q2: The brake does not release when the drive is enabled. The 24V brake coil supply is confirmed at the motor connector. Is the brake faulty?

With confirmed 24V at the motor connector, the brake coil may have failed open-circuit — no current, no magnetic field, brake stays applied. Measure the resistance across the brake coil terminals at the motor (with 24V disconnected). A healthy brake coil typically measures 15–30 Ω. Open circuit or significantly out of range confirms a failed brake coil.

Q3: After removing the tapered shaft hub, the shaft surface shows fretting marks. Does this affect the motor?

Light fretting on a tapered shaft is cosmetic and does not affect motor performance. If the fretting is deep enough to affect the taper fit — preventing the hub from seating concentric — the shaft surface may need light dressing by a qualified motor repair company before refitting. Never use a hub that rocks on the taper.

Q4: The A64 encoder alarm appears intermittently at high ambient temperature. What is likely?

Intermittent encoder alarms correlated with temperature point to connector contact resistance increasing as components expand thermally. Check the encoder connector at both the motor and the amplifier. Oxidised or slightly corroded contacts have higher resistance at temperature. Clean the contacts and reseat. If the alarm then occurs only when the motor itself is hot, the encoder electronics inside the motor may be degraded.

Q5: What is the long-term successor to the A06B-0373-B175?

FANUC's Alpha i series (αis or αif) motors replaced the original Alpha series. The current equivalent at the 2 Nm / 3000 rpm specification is found in the A06B-0202 or A06B-0371 series αis motors, paired with SVM modules from the A06B-6114 or A06B-6124 amplifier generation. Direct mechanical replacement requires confirming shaft and flange dimensions — some αi motors use a different flange format to the original Alpha red-cap series.