US Patent 10549954 Elevator system having linear drive

According to an aspect, an elevator system includes an elevator car 14 to travel in a hoistway 11 and a linear propulsion system 20 to impart force to the elevator car. The linear propulsion system includes a secondary portion 18 mounted to the elevator car and a primary portion 16 mounted in the hoistway. The primary portion includes a plurality of motor segments 26. The elevator system also includes a load sensor 52 operable to detect an elevator load on a brake. The elevator system further includes a control system 46 operable to apply an electrical current to at least one of the motor segments that overlaps the secondary portion, determine a measurement of the elevator load, and vary an electrical angle estimate while the brake is engaged and thrust is applied.