Method of applying brake to a hoist by electromagnetic means in a permanent magnet motor
First 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, andrepeating the generating control signals, applying a braking command signal and removing the braking command signal until the PM motor has stopped.
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Accused Products
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.
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Citations
17 Claims
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1. A permanent magnet (PM) motor driven hoist with motor based electromagnetic braking comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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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:
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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. - View Dependent Claims (14, 15, 16, 17)
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Specification