Control device for hoist and control method thereof
First Claim
1. A control device for a hoist comprising:
- a time setting unit for setting the time from startup of a double winding induction motor performing lifting or lowering by a first speed or a second speed lower than said first speed to disengage a brake which brakes said double winding induction motor, and setting 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 a generation of a torque; and
a time changing unit for detecting a power-supply frequency of a power supply supplying power to said hoist and capable of changing 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 comprising:
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a time setting unit for setting the time from startup of a double winding induction motor performing lifting or lowering by a first speed or a second speed lower than said first speed to disengage a brake which brakes said double winding induction motor, and setting 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 a generation of a torque; and a time changing unit for detecting a power-supply frequency of a power supply supplying power to said hoist and capable of changing 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 having a double winding induction motor which performs lifting or lowering by a first speed or by a second speed lower than said first speed, and a brake which brakes said double winding induction motor, said method comprising:
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detecting power-supply frequency of a power supplysupplying 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 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 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