Rotary Encoders Boast Of Accurate Rotor Position

Besides having standard data channels, the RCM and RCH series of incremental rotary encoders are able to develop output signals for commutation of brushless motors. The optically derived commutation signals are said to provide rotor position far more accurately than Hall devices, and the integration of these components into the encoder is said to reduce part count and assembly time. The commutation signals are created by scanning additional tracks on the encoder disk, and motors with any number of pole pairs can be accommodated. Alignment of the commutation signals with the motor windings is claimed to be straightforward, and can be done with the motor in a static position. The encoders are priced at $250 each.