An optical encoder and motor assembly, comprising: a motor and brake device, the motor and brake device including a motor shaft that rotates or remains stationary based on operation of the motor and brake device; an encoder housing including an opening ; an encoder shaft associated with the motor shaft so that the encoder shaft rotates relative to the encoder housing as the motor shaft rotates; an encoder disk secured to the encoder shaft , the encoder disk rotating with the encoder shaft , the encoder disk being within the encoder housing ; at least one detector within the encoder housing , the at least one detector being situated relative to the encoder disk to detect rotary movement of the encoder disk ; a motor and brake housing at least partially enclosing the motor and brake device, the motor and brake housing including at least one cavity aligned with the motor shaft , wherein the encoder housing is at least partially received in the at least one cavity , the encoder shaft being supported partially within the encoder housing and partially extending through the opening of the encoder housing ; a seal at an interface between the encoder shaft and the encoder housing , the seal surrounding the encoder shaft , the seal being outside of the encoder housing , the seal being situated to prevent contaminants from the cavity from entering the encoder housing through the opening ; and a packing inside the encoder housing between the opening and the encoder disk , the packing being situated to prevent any debris associated with rotation of the encoder shaft relative to the seal from contacting the encoder disk . a motor and brake device, the motor and brake device including a motor shaft that rotates or remains stationary based on operation of the motor and brake device; an encoder housing including an opening ; an encoder shaft associated with the motor shaft so that the encoder shaft rotates relative to the encoder housing as the motor shaft rotates; an encoder disk secured to the encoder shaft , the encoder disk rotating with the encoder shaft , the encoder disk being within the encoder housing ; at least one detector within the encoder housing , the at least one detector being situated relative to the encoder disk to detect rotary movement of the encoder disk ; a motor and brake housing at least partially enclosing the motor and brake device, the motor and brake housing including at least one cavity aligned with the motor shaft , wherein the encoder housing is at least partially received in the at least one cavity , the encoder shaft being supported partially within the encoder housing and partially extending through the opening of the encoder housing ; a seal at an interface between the encoder shaft and the encoder housing , the seal surrounding the encoder shaft , the seal being outside of the encoder housing , the seal being situated to prevent contaminants from the cavity from entering the encoder housing through the opening ; and a packing inside the encoder housing between the opening and the encoder disk , the packing being situated to prevent any debris associated with rotation of the encoder shaft relative to the seal from contacting the encoder disk . <EOS>