# US 10,501,293 B2 · Method of applying brake to a hoist by electromagnetic means in a permanent magnet motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,293 B2 - Document ID: US10501293B2 - Status: Granted - Kind: B2 - Application number: 15/471,452 - Filed: 2017-03-28 - Published: 2018-08-02 - Granted: 2019-12-10 - Earliest claimed: 2017-01-31 - Assignees: Goodrich Aerospace Services Private Limited - Applicants: Goodrich Aerospace Services Private Limited - Inventors: Ashok Kumar Thirunarayana; Adishesha Chinknyakanhalli Sivaramasastry - Web page: https://patentgrep.com/patent/US10501293B2 ## CPC - B66D 1/485: {electrical} - B66D 1/12: incorporating electric motors - B66D 1/22: Planetary or differential gearings (for actuating grab buckets B66D1/70 ){, i.e. with planet gears having movable axes of rotation} - H02P 3/04: Means for stopping or slowing by a separate brake, e.g. friction brake or eddy-current brake - H02P 3/08: for stopping or slowing a DC motor - H02P 3/24: by applying DC to the motor - B66D 2700/025: motor operated - B66D 2700/03: Mechanisms with latches or braking devices in general for capstans, hoists or similar devices as well as braking devices actuated electrically or by fluid under pressure - B66D: CAPSTANS; WINCHES; TACKLES, e.g. PULLEY BLOCKS; HOISTS (winding or unwinding ropes or cables for feeding or storage purposes B65H; rope or cable winding or unwinding mechanisms for lifts B66B) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract Embodiments herein relate to a permanent magnet (PM) motor driven hoist with a motor based electromagnetic brake. The hoist includes a direct current (DC) power source, a PM motor having stator coils and a PM rotor operably coupled to a cable drum with a cable wrapped thereon. The hoist also includes a controller operably connected to the direct current power source and the PM motor, wherein the controller is configured to control the PM motor employing a method to brake the PM motor. The method includes generating control signals in the controller based on a position of the PM motor, applying a braking command signal to the PM motor to magnetically lock the PM rotor of the PM motor for a selected duration, removing the braking command signals for a second selected duration, and repeating the generating, applying, and removing until the PM motor has stopped. ## Claims ### Claim 1 A permanent magnet (PM) motor driven hoist with motor based electromagnetic braking comprising: a direct current (DC) power source; a PM motor having stator coils and a PM rotor operably coupled to a cable drum with a cable wrapped thereon; and a controller operably connected to the direct current power source and the PM motor, wherein the controller is configured to control the PM motor employing a method to brake the PM motor comprising; generating control signals in the controller based on a position of the PM motor, applying a braking command signal to the PM motor to magnetically lock the PM rotor of the PM motor for a selected duration, removing the braking command signals for a second selected duration, and repeating the generating control signals, applying a braking command signal and removing the braking command signal until the PM motor has stopped. ### Claim 2 (depends on 1) The hoist of claim 1, further including a gear train operably coupled to the PM motor and the cable drum. ### Claim 3 (depends on 1) The hoist of claim 1, further including an electromechanical brake operably coupled to the controller and the cable drum. ### Claim 4 (depends on 3) The hoist of claim 3, wherein the electromechanical brake is energized when the PM motor is not commanded to move by the controller. ### Claim 5 (depends on 3) The hoist of claim 3 wherein the electromechanical brake is energized when the PM motor is commanded to move by the controller. ### Claim 6 (depends on 3) The hoist of claim 3, wherein the electromechanical brake is configured to arrest the motion of the cable drum and hold the cable drum in a fixed position under selected conditions. ### Claim 7 (depends on 1) The hoist of claim 1, further including a plurality of Hall effect sensors configured to detect the position of a rotor of the PM motor. ### Claim 8 (depends on 1) The hoist of claim 1, wherein the PM motor is at least one of a brushless direct current BLDC motor, a Permanent Magnet Synchronous Motor and a Reluctance motors. ### Claim 9 (depends on 1) The hoist of claim 1, wherein the controller includes an inverter for generating command signals to the PM motor. ### Claim 10 (depends on 9) The hoist of claim 9, wherein the inverter includes at least six switching devices arranged in three legs. ### Claim 11 (depends on 1) The hoist of claim 1, wherein the braking command signals are pulse width modulated (PWM) based on an operational characteristic of the PM motor. ### Claim 12 (depends on 1) The hoist of claim 1, wherein the braking command signals are configurable for a given hoist configuration. ### Claim 13 A method of applying a brake in a hoist system with an permanent magnet (PM) motor operably connected to a cable drum with a cable wrapped thereon, a controller operably connected the PM motor and a direct current power source, the controller executing the method comprising: generating control signals in the controller based on a position of the PM motor; applying a braking command signals to the PM motor to magnetically lock the PM motor for a selected duration; removing the braking command signals for a second selected duration; and repeating the generating, applying and removing until the PM motor has stopped. ### Claim 14 (depends on 13) The method of claim 13, further including energizing an electromechanical brake when the PM motor is not commanded to move by the controller, wherein the electromechanical brake is configured to arrest the motion of the cable drum and hold the cable drum in a fixed position under selected conditions. ### Claim 15 (depends on 13) The method of claim 13, further including energizing an electromechanical brake when the PM motor is commanded to move by the controller, wherein the electromechanical brake is configured to arrest the motion of the cable drum and hold the cable drum in a fixed position under selected conditions. ### Claim 16 (depends on 13) The method of claim 13, wherein the braking command signals are pulse width modulated (PWM) based on an operational characteristic of the PM motor. ### Claim 17 (depends on 13) The method of claim 13, wherein the braking command signals are configurable for a given hoist configuration.