B&R’s 8JS synchronous motor family is a line of permanent-magnet, electronically commutated three-phase motors built for applications that need high dynamics, compact size, and precise positioning.
The motors use sinusoidal commutation with either EnDat absolute encoders or resolver feedback, a star-connected three-phase winding, and a rotor design optimized for low inertia, high overload capability, and reduced torque ripple for strong dynamic torque even at higher speeds. In the standard industrial variants, the motors are self-cooled through the mounting flange which serves as a cooling surface, connect via two circular connectors, and are designed as largely wear-free units aside from the greased, preloaded ball bearings. The series spans broad speed and torque performance including nominal speeds up to 8,000 rpm and stall torques ranging roughly from under 1 Nm into the tens of Nm depending on configuration, with options such as holding brakes, shaft variants, and encoder single-turn or multi-turn capability that can store many revolutions for absolute positioning. For hygienic environments, stainless-steel 8JS variants are designed for efficient washdown with an IP69K-rated smooth housing concept, use a single “hybrid” motor cable that combines power and encoder signals with EnDat feedback, and employ externally visible FDA-compliant materials for applications with indirect contact to foodstuffs.
