Encoder Eccentricity Correction For Elevator Systems

A method of correcting for eccentricity of an encoder in an elevator system, comprising:

• using a first sensor to detect a first velocity at which a portion of an encoder wheel moves relative to the first sensor, the encoder wheel being axially coupled to a motor rotor of an elevator system;
• using a second sensor to simultaneously detect a second velocity at which a portion of the encoder wheel moves relative to the second sensor, the second sensor positioned approximately 180 encoder wheel degrees apart from the first sensor;
• and
• averaging the first velocity and the second velocity to determine a corrected rotational velocity of the motor rotor.

A system, comprising:

• a motor comprising a rotor;
• and
• an encoder, to determine a rotational speed of the rotor, the encoder comprising:
• an encoder wheel, axially coupled to the rotor;
• a plurality of sensors, fixed at predetermined positions relative to the encoder wheel, each of the plurality of sensors configured to determine a speed at which the encoder wheel passes by the sensor;
• and
• a processor to receive inputs from the plurality of sensors related to the determined speeds, the processor configured to determine an actual speed of rotation of the motor based on the received inputs.