CONTROL DEVICE FOR HOIST AND CONTROL METHOD THEREOF
First Claim
1. A control device for a hoist, wherein the control device has:
- a time setting unit which sets the time from startup of a double winding induction motor which performs lifting or lowering by a first speed or by a second speed which is lower than said first speed to disengagement of a brake which brakes said double winding induction motor and the time from start of engagement of said brake to stopping of said double winding induction motor in accordance with the time from the startup of said double winding induction motor to generation of torque; and
a time changing unit which detects power-supply frequency of a power supply which supplies power to said hoist and can change at least one of the time from the startup of said double winding induction motor to the disengagement of said brake and the time from the start of engagement of said brake to the stopping of said double winding induction motor in accordance with the power-supply frequency of said power supply.
1 Assignment
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Accused Products
Abstract
A control device for a hoist, which enables easy judgment of the lifetime of a brake of a hoist is provided. The time setting unit sets the time from startup of a double winding induction motor to disengagement of the brake and the time from start of engagement of the brake to stopping of the double winding induction motor in accordance with the time from the startup of the double winding induction motor to generation of torque. The time changing unit detects if power-supply frequency of a power supply is 50 Hz or 60 Hz and can change at least one of the time from the startup of the double winding induction motor to the disengagement of the brake and the time from stopping of driving of the brake to stopping of double winding induction motor in accordance with the power-supply frequency of the power supply.
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Citations
7 Claims
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1. A control device for a hoist, wherein the control device has:
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a time setting unit which sets the time from startup of a double winding induction motor which performs lifting or lowering by a first speed or by a second speed which is lower than said first speed to disengagement of a brake which brakes said double winding induction motor and the time from start of engagement of said brake to stopping of said double winding induction motor in accordance with the time from the startup of said double winding induction motor to generation of torque; and a time changing unit which detects power-supply frequency of a power supply which supplies power to said hoist and can change at least one of the time from the startup of said double winding induction motor to the disengagement of said brake and the time from the start of engagement of said brake to the stopping of said double winding induction motor in accordance with the power-supply frequency of said power supply. - View Dependent Claims (2, 3, 4, 5, 7)
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6. A method of controlling a hoist which has a double winding induction motor which performs lifting or lowering by a first speed or by a second speed which is lower than said first speed and a brake which brakes said double winding induction motor, said method comprising steps of:
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detecting power-supply frequency of a power supply which supplies power to said double winding induction motor; and changing at least one of the time from startup of the double winding induction motor to disengagement of the brake, which is set in accordance with the time from the startup of said double winding induction motor to generation of torque, and the time from the startup of said double winding induction motor to stopping of said double winding induction motor, which is set in accordance with the time from the startup of said double winding induction motor to the generation of torque, in accordance with the power-supply frequency of said power supply.
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Specification