FANUC A06B-2238-B300 αiS 12/4000-B Servo Motor with Tapered Shaft and Brake

Unlike the no-brake B000 configuration, the B300 can hold a stationary motor shaft after controlled deceleration and brake engagement. Shaft geometry, brake circuit and feedback compatibility must all match the original installation.

Verified αiS 12/4000-B Specifications

• Manufacturer: FANUC
• Part number: A06B-2238-B300
• Motor model: αiS 12/4000-B
• Rated output: 2.7 kW
• Continuous torque at low speed: 12 N·m
• Continuous current at low speed: 13.4 A RMS
• Rated speed: 3,000 min⁻¹
• Maximum speed: 4,000 min⁻¹
• Maximum motor torque: 46 N·m
• Output shaft: Tapered shaft
• Feedback: αiA 4000 absolute pulse coder
• Brake: Built-in holding brake
• Brake supply: 24 VDC ±10%
• Brake holding torque: 8 N·m
• Brake current: 1.1 A

8 N·m Holding Brake Function

The internal brake is intended to hold an already stationary shaft. It must not be used as a service brake for repeatedly stopping a rotating motor. The servo system should decelerate the axis first and apply the brake through the machine's original control sequence.

Brake power and release timing must follow the FANUC machine design. A separate, correctly rated 24 VDC brake supply is normally required rather than sharing the CNC or amplifier control-power circuit.

Tapered Shaft and αiA 4000 Feedback

The tapered shaft must fit the original coupling or mechanical assembly. The αiA 4000 pulse coder returns absolute position and speed data to the servo system. Check the backup battery and follow the approved encoder-disconnection procedure before removing the motor.

B000, B300 and B320 Identification

A06B-2238-B000 uses a tapered shaft without a brake. A06B-2238-B300 adds the standard holding brake, while A06B-2238-B320 is identified separately as a high-power or high-torque brake configuration. These versions should not be substituted solely because the motor model is αiS 12/4000-B.

IP65 and IP67 Protection Versions

The standard A06B-2238-B300 is an IP65 motor configuration. Versions such as A06B-2238-B300#0100 and certain other specified suffixes are identified as IP67. Always match the complete suffix when sealing or coolant exposure is important.

Replacement Compatibility Check

Before ordering, verify the complete FANUC number, tapered shaft, standard-brake requirement, 24 VDC brake circuit, αiA 4000 feedback, connectors, mounting dimensions, compatible servo amplifier and CNC motor parameters.

100% Tested Supply from REACO CNC

REACO CNC supplies the FANUC A06B-2238-B300 servo motor for machine maintenance and replacement. Every available unit is 100% tested before shipment. Send us the original motor nameplate and connector photos if you need help confirming the configuration.

Worldwide DHL/UPS/FedEx shipping. Contact REACO CNC for current stock, condition, price and delivery time.