CONTROL DEVICE FOR HOIST AND CONTROL METHOD THEREOF

• US 20120185084A1
• Filed: 09/29/2010
• Published: 07/19/2012
• Est. Priority Date: 09/30/2009
• Status: Active Grant

• Current Assignee: KITO Corporation
• Original Assignee: KITO Corporation
• Inventors: Maruno, Masaharu, Matsuo, Daisuke, Furukawa, Kazuho
• Granted Patent: US 8,729,836 B2
• Time in Patent Office: Days
• US Class Current: 700/228
• CPC Class Codes: B66D 1/14 Power transmissions between power sources and drums or barrels including brakes, one-way brakes, one-way clutches, clutches activated alternately with brakes, fixed ratio gearing unless otherwise provided for in B66D1/16 - B66D1/24
• CPC Class Codes: B66D 3/18 Power-operated hoists
• CPC Class Codes: B66D 5/30 electrical
• CPC Class Codes: H02P 2207/076 wherein both supplies are made via converters: especially doubly-fed induction machines; e.g. for starting
• CPC Class Codes: H02P 3/04 Means for stopping or slowing by a separate brake, e.g. friction brake or eddy-current brake

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.

Claims

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.

2. A control device for a hoist according to claim 1, further having

an engagement time detection unit which detects an engagement time of said brake and

a replacement timing judgment unit which judges a replacement timing of the brake based on the engagement time which is detected by said engagement time detection unit.

3. A control device for a hoist according to claim 1, wherein said time setting unit sets 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 a manner changeable by parameters.

4. A control device for a hoist according to claim 1, further having an induction motor instruction unit which instructs said double winding induction motor to stop after switching from the lifting or the lowering at said first speed to the lifting or the lowering at said second speed when the lifting or the lowering at said first speed is performed.

5. A control device for a hoist according to claim 1, further having an induction motor instruction unit which instructs said double winding induction motor to switch from the lifting or the lowering at said second speed after the startup to the lifting or the lowering at said first speed when the lifting or the lowering at said first speed is performed.

7. A control device for a hoist according to claim 2, wherein said time setting unit sets 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 a manner changeable by parameters.

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:

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.