Product Description:

Bosch Rexroth Indramat supplies the 1MR240F-A072, a rotor built for integration inside the frameless 1MB High-Speed Asynchronous Motors series. The component forms the rotating core of a spindle motor; when paired with a stator and drive electronics, it converts the stator’s alternating field into mechanical rotation for machining centers, grinding heads, and other high-speed automation axes. By separating the rotor and stator, machine builders can mount the active parts directly into the spindle housing, reducing envelope and improving dynamic balance for precision work. This frameless arrangement is commonly used where the spindle structure itself serves as the motor housing and where compact radial dimensions are important.

Its frame size of 240 millimeters sets the outside diameter for the matching stator. A nominal supply of 145 V supports constant-power operation and delivers up to 13 kW. At that operating point, the circuit produces 123 Nm while drawing 74 A. During acceleration, the drive can momentarily permit 164.2 A, allowing the rotor to reach 307 Nm without exceeding thermal limits. The separation between continuous output and short-term overload suits spindle axes that must hold speed in a cut and still accelerate quickly between operations.

The rotor bore is 72 mm, matching shaft assemblies that use a step interference fit for this design. The rotor uses two pole pairs, so synchronous speed calculations remain straightforward for vector drives. Length code F corresponds to the active stack height, and the 25 mm² power-wire cross-section helps limit conductor heating. Rotor mass is 29.9 kg, and the polar inertia is 0.12 kg·m², which helps reduce overshoot during speed changes. A torque constant of 1.91 Nm/A, winding resistance of 0.143 Ω, and inductance of 1.29 mH support stable current response in milling, drilling, and grinding equipment. These values are also relevant when sizing the matching inverter and cabling.