Product Description:

The 1MS140B-4B-A2 is a stator subassembly produced by Bosch Rexroth Indramat for integration into the 1MB High-Speed Asynchronous Motors series. Designed as the stationary electromagnetic section of a frameless spindle motor, it generates the rotating magnetic field that interacts with a separate rotor to deliver torque. In automated machine tools, this stator supports high-speed cutting or grinding spindles with precise inverter-controlled induction power while minimizing overall package size because no external housing is required.

A prominent feature of the unit is its liquid cooling arrangement; coolant circulates around the windings to keep thermal rise within limits during continuous high-frequency operation. The coolant flows through an integrated aluminum cooling jacket, so heat is transferred directly to the machine’s central chiller rather than to the surrounding air. Mechanical dimensions are fixed by frame size 140, giving the stator an outside diameter matched to companion rotors of the same frame family. The shaft-parallel build identified by motor length code B sets the axial stack height, balancing copper volume against installation depth. Factory wiring arrives as a 1.5 m loom that exits cleanly through one stator end to simplify routing toward the drive cabinet.

The electromagnetic layout follows winding variant 4B, a pattern that sets the resistance, inductance, and base frequency used for dynamic spindle acceleration. Because it is supplied as a stator for a 1MB frameless spindle motor, the component mounts directly inside the machine’s bearing cartridge, eliminating redundant housings and reducing the rotor-to-stator air gap. It is intended for use with Bosch Rexroth Indramat drives, and its geometry aligns with other members of the 1MB High-Speed Asynchronous Motors series.