Product Description:

The 1MS270C-4B-A2 is a stator assembly manufactured by Bosch Rexroth Indramat for the 1MB High-Speed Asynchronous Motors series. It forms the electromagnetic core of a frameless spindle motor, supplying the concentric windings that establish the rotating field once mated to a compatible rotor sleeve. By separating the stator from a conventional housing, the assembly can be mounted directly inside a spindle cartridge or gantry, which helps reduce radial runout and shorten the drive train in high-speed milling, drilling, or grinding equipment used in industrial automation.

The thermal design centers on liquid cooling, which removes heat through continuously circulated coolant rather than relying on ambient air. An outer sleeve made from aluminum conducts losses from the copper slots to the fluid path quickly, which helps preserve insulation life during high-frequency operation. Power and sensor leads leave the winding through a 1.5 m loom that is routed through the stator end, so all cabling exits axially and avoids interference with spindle clamping fixtures. The magnetic stack corresponds to frame size 270, giving a 270 mm outside diameter that accommodates large shaft bores without compromising slot area.

The active iron stack matches motor length code C, providing a mid-range axial dimension suited to compact tool spindles that still require moderate continuous power. Coil turn count and conductor gauge follow winding variant 4B, matching impedance and back-EMF to inverters that supply high fundamental frequencies. A surrounding cooling jacket delivers the coolant evenly around the circumference, helping keep temperature rise predictable during sustained high-speed duty cycles. Supplied as a stator for a 1MB frameless spindle motor, the unit is intended for use with compatible rotors, seals, and balancing components.