Winding machine stopping method

Abstract

A method of stopping of a winding machine that hoists and lowers an object prevents abrasion of the electromagnetic brake and the descent of load. The winding machine, which winches a load up or down in response to a torque command TREF to the electric motor M produced by the speed controller ASR in accordance with the a speed command N REF generated by the speed command generation circuit NRC, operates at the stopping of the machine to cease the motor control if the motor speed N FB is zero after the torque command to the motor M is brought to zero for a predetermined length of time following the issuance of a brake command to the electromagnetic brake which is coupled directly to the motor M.

I claim:  
     
       1. A method of stopping of a winding machine which operates to winch a load up or down in response to a torque command for controlling an electric motor where said torque command is produced by a speed controller in accordance with a speed command generated by a speed command generation circuit, said method comprising the steps of: 
       decreasing the speed command for said electric motor to zero for a predetermined length of time when stopping the electric motor;  
       detecting a motor speed N FB  of said electric motor using a speed detector;  
       braking said motor by issuing a brake command to an electromagnetic brake coupled to said electric motor after said motor speed N FB  of said electric motor has reached zero and a second predetermined length of time following said motor speed reaching zero has expired;  
       reducing said torque command to zero following engagement period of said electromagnetic brake;  
       detecting the electric motor speed after said torque command is zero; and  
       turning off a power supply for the electric motor if the electric motor speed N FB  detected by the speed detector is zero following said torque command reaching zero.  
     
     
       2. A method of stopping of a winding machine according to  claim 1 , wherein in said braking step, a timer is operated to measure said second predetermined time period after the motor speed has reached zero, and said brake command is issued by a brake command generation circuit to said electromagnetic brake when a counter value of said timer is greater than a prescribed value to activate said electromagnetic brake. 
     
     
       3. A method of stopping a winding machine wherein the finding machine includes an electric motor coupled to an ectromagnetic brake, a speed command generation circuit for generating a speed command, a speed detector for detecting a speed of said electric motor and outputting a tested speed, a speed controller circuit for receiving a difference between the speed command and the detected speed of the electric motor and generating a torque command means for driving the electric motor in accordance with said torque command, and a brake command circuit for driving said electromagnetic brake in accordance with a stop command and said detected speed, the method comprising the steps of: 
       issuing said stop command to the brake command circuit and the speed command generation circuit;  
       said speed command generation circuit outputting a speed reduction to zero command to the speed controller circuit in response to receiving the stop command to reduce a speed of said electric motor to zero;  
       said brake command circuit, in response to receiving said stop command and receiving a detected speed from the speed detecting circuit and determining that said detected speed is zero, executing a first predetermined delay period and issuing a brake command to said electromagnetic brake at a completion of said predetermined delay period to apply a braking force to the electric motor;  
       said means for driving the electric motor reducing a torque of said electric motor to zero following a second predetermined delay period after issuance of said brake command which allows for activation of said electromagnetic brake; and  
       said means for driving the electric motor releasing control of said electric motor by ceasing a current applied thereto after completion of reducing said torque of said motor to zero and expiration of a third predetermined time period when said detected motor speed remains at zero indicating that said electromagnetic brake is functionally engaged.  
     
     
       4. A method of controlling an electric motor, comprising: 
       
         decreasing a speed command for the electric motor to zero for a predetermined length of time when stopping the electric motor;  
       
       
         detecting a motor speed of said electric motor using a speed detector:  
       
       
         braking said motor by issuing a brake command to an electromagnetic brake coupled to said electric motor after said motor speed of said electric motor has reached zero and a second predetermined length of time following said motor speed reaching zero bas expired;  
       
       
         reducing said torque command, which controls said electric motor, to zero following engagement period of said electromagnetic brake;  
       
       
         detecting the electric motor speed after said torque command is zero: and  
       
       
         turning off a power supply for the electric motor if the electric motor speed detected by the speed detector is zero following said torque command reaching zero. 
       
     
     
       5. The method according to  claim 4 , wherein in said braking operation, a timer is operated to measure said second predetermined time period after the motor speed has reached zero, and said brake command is issued by a brake command generation circuit to said electromagnetic brake when a counter value of said timer is greater than a prescribed value to activate said electromagnetic brake. 
     
     
       6. A method of controlling an electric motor, comprising: 
       issuing a stop command to a brake command circuit and a speed command generation circuit,  
       
         wherein said speed command generation circuit outputs a speed reduction to zero command to a speed controller circuit in response to receiving the stop command to reduce a speed of said electric motor to zero;  
       
       
         wherein said brake command circuit, in response to receiving said stop command and a detected speed of said electric motor from a speed detecting circuit and determining that said detected speed is zero, executes a first predetermined delay period and issues a brake command to an electromagnetic brake at a completion of said predetermined delay period to apply a braking force to the electric motor;  
       
       
         reducing a torque of said electric motor to zero following a second predetermined delay period after issuance of said brake command which allows for activation of said electromagnetic brake: and  
       
       
         releasing control of said electric motor by ceasing a current applied thereto after completion of reducing said torque of said motor to zero and expiration of a third predetermined time period when said detected motor speed remains at zero indicating that said electromagnetic brake is functionally engaged.