Product Description:

The SF-A4.0125.030-14.155 is a servo motor manufactured by Bosch Rexroth Indramat as part of the SF Servo Motors series. It supplies precise rotational output for closed-loop axes in automated assemblies, translating command currents into repeatable torque and speed profiles required by pick-and-place modules, feeders, and packaging stations. Integrated feedback and a holding brake are contained in the same frame, allowing machine builders to reduce wiring runs and maintain a compact layout.

During continuous motion, the shaft reaches a rated velocity of 3000 rpm and supports an allowable axial thrust of 154 N. The permanent-magnet motor operates from a DC bus of 670 VDC, allowing it to connect to compatible Rexroth converters that use this intermediate-circuit voltage. Position feedback is handled by a high-density optical encoder that produces 8 million increments per revolution and maintains a precision of ±20 arcseconds for fine indexing. A normally closed holding brake counters back-driving forces with 18 Nm of static torque, while its friction surfaces add only 3.1 × 10⁻⁴ kg·m² of inertia to the load side. The brake engages 25 ms after power is removed and releases fully 50 ms after power is applied. Its coil draws 0.7 A during release.

Each ampere delivered by the controller generates 1.37 Nm/A of torque. The motor withstands a momentary stall load of 14.5 Nm when 10.6 A of locked-rotor current is applied. The bare rotor has a mass moment of inertia of 30 × 10⁻⁴ kg·m², supporting fast acceleration without excessive overshoot during light pick cycles. Brake actuation relies on a dedicated 24 VDC supply, allowing the clamping mechanism to operate during emergency stops and power-off conditions while preserving encoder alignment. The normally closed design holds the shaft when electrical power is unavailable, helping prevent an attached load from moving unexpectedly. Separate brake control also allows the drive to coordinate shaft release with the start of commanded motor torque.