Rotor Positioning Sensor Bearing Units
A complete bearing and encoder assembly that sits at the non-drive end of a motor and tells the drive exactly where the rotor is. Commutation, speed and position all come from one component that is already concentric with the shaft. SES holds the range as an authorised SKF distributor, covering construction Deep groove ball bearing with integrated sensor body; signal type Incremental quadrature, some executions with commutation tracks; mounting Fitted into the motor end shield as a normal bearing; concentricity Determined by the bearing seat, not by a coupling. Executions include units with incremental output only, units with commutation tracks for brushless motors, high-resolution executions for positioning duty, units with connector body for plug-in motors. It is specified most often into servo drives on rolling mill entry and exit tables and positioning drives on CNC machine tools in workshop bays. Every part is genuine SKF through official channels, with designation, specification and options confirmed against your duty before it ships — supplied from Kolkata and our branch network, with breakdown cover that does not sit in an inbox.
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From integrated steel plants to power utilities and EPC majors — the works that cannot afford a counterfeit part specify through SES.
Function
Rotor angle + speed to the drive
Built-in
Bearing, impulse ring and sensor body
Alignment
Set by the bearing seat, no field setting
Typical host
Servo and PM motors under closed loop
Where it runs.
You will find Rotor Positioning Sensor Bearing Units in the parts of a plant where this particular duty actually occurs. In practice that means servo drives on rolling mill entry and exit tables, positioning drives on CNC machine tools in workshop bays, hoist and long-travel drives on process cranes, and equally packing line indexers in cement and fertiliser bagging, extruder and winder drives in film and paper plant. What links them is the duty rather than the machine name — function: Rotor angle + speed to the drive. If your installation is not on that list it matters less than you would think: the operating condition decides the specification. Send us the load, the speed, the running temperature and the environment it runs in, and we will match it to the right execution in the SKF range and confirm what is in stock.
Specify it against the duty.
Specification here follows the operating condition, not the catalogue. Motor is rewound or the rotor is changed — Re-index the impulse ring to the rotor pole position given by the motor maker. An offset commutation angle draws heavy current at zero speed and cooks the winding within a shift. Drive is a modern PWM inverter switching at high frequency — Route the encoder lead in a separate tray from the motor cable and use screened, twisted pairs. Common-mode noise coupled into the signal reads as false position and the axis hunts. Motor is mounted vertically with the sensor end down — Specify the drain or drip-loop arrangement suited to that orientation. Condensate collecting in the sensor cavity shorts the head and the whole unit is scrap. Where two of those apply at once, specify for the harsher of the two — under-specifying is what puts the part back on the bench a month later. Send us the duty and we will confirm the execution.
Ordering this from SES.
Keep the original wiring diagram with the spare. Channel swapping on refit reverses the sense of rotation seen by the drive, and the first thing that happens is the axis runs away into its end stop. Send the designation off the failed part and we will confirm the SKF equivalent and stock position.