Fanuc A06B-0116-B204 | BiS Series AC Servo Motor 1/6000 — B64iA Encoder, Keyed Shaft

Part Number: A06B-0116-B204

Series: BiS AC Servo Motor

Model: BiS 1 / 6000

Condition: New / Refurbished / Exchange Available

Overview

The Fanuc A06B-0116-B204 is a high-speed AC servo motor from Fanuc's BiS series — a generation that brought absolute encoder technology and refined drive integration to a wide range of CNC machine tool applications.

Rated at 5 kW output and 6,000 RPM maximum speed, this motor operates at the high end of the speed spectrum for its class, which makes it well suited to direct-drive spindle assist axes, high-traverse linear axis drives, and any CNC application where fast positioning and dynamic response are as important as raw torque.

Fitted with the B64iA absolute encoder and a keyed straight shaft, the A06B-0116-B204 is designed for installations where shaft coupling integrity and precise position feedback without homing dependency are both requirements.

The motor runs on a 200–240 VAC input supply at 50/60 Hz — standard industrial supply voltage globally — and generates its 172 V, 400 Hz operating condition through the connected Fanuc servo amplifier. At 1.4 kg, it is a remarkably compact unit for its output rating, reflecting the high power density that characterises the BiS series design.

Key Specifications

High Speed, High Power Density

What stands out immediately about the A06B-0116-B204 is the combination of 5 kW output and 6,000 RPM in a 1.4 kg package. That power-to-weight ratio is not accidental — the BiS series was designed with compact machine tool formats in mind, where envelope constraints around the axis drive area are real and a bulky motor simply does not fit the machine architecture.

Getting 5 kW of servo output from a motor weighing less than a typical household kettle requires tight electromagnetic design and efficient thermal management.

The 400 Hz operating frequency is what enables the 6,000 RPM speed rating.

Higher electrical frequency allows higher synchronous speeds, and the servo amplifier manages this through its drive output stage — the 200–240 VAC input supply is rectified and then inverted to the motor's operating frequency under drive control.

The end user sees a standard industrial supply connection at the drive input; the 172 V / 400 Hz condition is internal to the drive-motor system.

For applications where rapid traverse rates, fast tool change positioning, or high-speed contouring are priorities, the 6,000 RPM ceiling of this motor delivers meaningfully better cycle times compared to the 2,000 or 3,000 RPM motors that were standard on lower-speed axis configurations.

B64iA Absolute Encoder

The B64iA is an absolute serial encoder — one of the key differentiators of the BiS series over earlier incremental encoder motor generations. An absolute encoder retains position data even when the machine is powered down, which eliminates the homing cycle on startup.

When power is restored, the CNC immediately knows the exact position of every axis fitted with a BiS motor, without needing to drive each axis to a reference point first.

In production environments, this is a genuine operational advantage.

Machines with absolute feedback resume from exactly where they shut down — useful after scheduled maintenance windows, unplanned power interruptions, or emergency stops mid-cycle.

It also simplifies the machine startup sequence and reduces the risk of axis reference errors that can occur if an incremental homing routine is interrupted or completed incorrectly.

The 64-bit resolution architecture of the B64iA provides very fine position granularity, which supports the high-accuracy positioning that modern CNC machining demands.

When replacing the A06B-0116-B204, the replacement unit must carry the same B64iA encoder specification — substituting a different encoder type requires servo drive parameter changes and may affect absolute position retention behaviour.

Keyed Shaft Configuration

The keyed straight shaft on this motor provides a positive, slip-resistant mechanical connection to couplings, pulleys, or direct-drive components. At 6,000 RPM and 5 kW, the torque loads involved — particularly during rapid acceleration and deceleration — are significant, and a keyed interface ensures the coupling cannot slip relative to the shaft under dynamic conditions that a clamping-only plain shaft coupling might not handle without risk of micro-movement over time.

The key also simplifies assembly and disassembly in the field. When the coupling hub is removed and reinstalled during maintenance, the key ensures it goes back in the same angular position every time, which matters for applications where coupling phase alignment affects system performance.

Ensure the replacement motor's keyway dimensions are verified against the existing coupling hub before installation.

Drive & Control Compatibility

The A06B-0116-B204 is designed for use with Fanuc's digital servo amplifier systems compatible with the BiS motor series — including αi series servo drives — and integrates with Fanuc CNC control platforms from the 0i, 16i, 18i, 21i, and 30i/31i/32i families, as well as the Fanuc Power Motion i platform.

The absolute encoder interface requires that the servo drive supports BiS series feedback — older analogue or early digital drive generations may not be compatible without additional hardware.

Servo drive parameters must be configured with the correct motor type code for the BiS 1/6000 specification.

Given the high operating speed and the absolute encoder behaviour, parameter verification during commissioning is not optional — an incorrectly configured drive will either fault on motor type mismatch or produce incorrect speed scaling that becomes apparent during axis rapid moves.

Sourcing & Condition Notes

The A06B-0116-B204 is available through specialist servo motor suppliers as a refurbished or surplus unit. Given the B64iA absolute encoder's role in machine startup behaviour, encoder condition is a priority inspection item on any used unit.

Verify the encoder battery (where applicable for absolute data retention) is current, and confirm the encoder cable connector is undamaged. Check the keyed shaft for fretting at the keyway and bearing condition by rotating the shaft by hand.

Winding resistance should be balanced across all three phases, with healthy insulation resistance to earth. Any unit with a history of overspeed events or excessive duty cycle should be fully bench tested before installation in a production machine.

FAQ

Q1: What makes the B64iA encoder different from the incremental encoders used on older Fanuc servo motors?

The B64iA is an absolute encoder — it stores shaft position data continuously, including when the machine is powered off. On startup, the CNC reads the current absolute position directly without running a homing sequence.

Incremental encoders lose position reference on power-down and require the axis to physically travel to a reference point before the machine can operate. For production environments, absolute feedback means faster restarts and no risk of reference cycle errors.

Q2: What servo amplifier and CNC control is this motor compatible with?

The A06B-0116-B204 is compatible with Fanuc αi series digital servo amplifiers and CNC control platforms including the 0i, 16i, 18i, 21i, and 30i/31i/32i families. The drive must support BiS series absolute encoder feedback.

Older Fanuc drive generations that predate the BiS motor series may not interface correctly with the B64iA encoder without hardware adaptation. Confirm compatibility at the drive level before specifying this motor for a retrofit application.

Q3: Why does this motor run at 400 Hz when the input supply is 50/60 Hz?

The 400 Hz refers to the motor's internal operating frequency — the electrical frequency the servo amplifier generates to drive the motor windings at 6,000 RPM. The amplifier takes the standard 200–240 VAC / 50–60 Hz mains input, rectifies it to a DC bus, and then inverts it to a variable frequency output matched to the motor speed command.

The 400 Hz figure is the rated operating point at maximum speed, not the supply frequency.

Q4: The motor weighs only 1.4 kg but is rated at 5 kW — is that accurate?

Yes. The BiS series was engineered for high power density in a compact package, which is a deliberate design priority for small-format CNC machine tools.

Modern servo motor design achieves this through optimised lamination geometry, high-energy permanent magnets, and efficient thermal management.

The 1.4 kg weight is accurate for this frame size at this output — it is one of the more notable characteristics of the BiS 1 motor in the 5 kW output class.

Q5: Can the keyed shaft variant be used in a plain shaft coupling arrangement?

Yes, a keyed shaft motor can be used with a plain bore clamping coupling — the key is simply left in place or removed, and the coupling hub grips the shaft diameter. However, if the coupling bore is sized for a plain shaft without a keyway slot, the hub will not seat fully over the keyed section.

In that case, either the coupling hub needs to be replaced with a keyed version or re-bored to accept the key. Do not attempt to file down the keyway or modify the motor shaft in the field — this affects shaft balance and integrity at 6,000 RPM.