JPH04333623A - Method for stopping spindle of spinning frame and apparatus therefor - Google Patents

Abstract

PURPOSE:To stop the subject apparatus without causing the generation of snarl, the disengagement of thread from a traveler and the end breakage by first applying strong brake with high DC voltage and changing to a low DC voltage to weaken the braking force after lowering the rotational speed of the spindle. CONSTITUTION:The primary side of an induction motor M for driving a spindle 1 is disconnected from an AC power source and a DC voltage is applied to the primary side to excite the motor and stop the spindle 1 of a spinning frame by the dynamic braking with the induction motor M. In the above process, strong brake is applied by applying high DC voltage to the primary side of the spindle-driving induction motor M connected to an AC power source through an inverter 2 after disconnecting the motor from the AC power source, the rotational speed of the spindle 1 is detected by a detector 11 and, when the rotational speed is decreased to a sufficiently low level, the braking force is weakened by switching the DC voltage to a low level by a controller 12. The spindle 1 of the spinning frame can be smoothly stopped while preventing the reverse rotation of the spindle 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for stopping a spindle of a spinning machine, and more particularly, to a method for stopping a spindle of a spinning machine and an apparatus therefor, and in particular, the primary side of an induction motor that drives the spindle is separated from an AC power source, and a DC voltage is applied to the primary side to excite it. The present invention relates to a method and apparatus for stopping the spindle of a spinning machine by applying dynamic braking to the induction motor, that is, stopping the spindle of a spinning machine by dynamic braking of the induction motor.

0002

2. Description of the Related Art As shown in FIG. 4, a conventional spindle stop device for a spinning machine using a dynamic break includes an induction motor M connected to an AC power source via an inverter 2 and driving a spindle 1; This induction motor M
It consists of a transformer 5 for applying a DC voltage to the DC voltage, a rectifier 6, and a DC voltage applying means consisting of a switch 7. At the same time as the AC power supply is cut off from the induction motor M, the switch 7 closes, and the rectifier 6 The induction motor M is stopped by applying a high DC voltage, that is, the spindle 1 of the spinning machine is stopped (see Japanese Patent Laid-Open No. 55-40852). Note that 3 is a relay for inverter operation/stop.

0003

[Problem to be Solved by the Invention] When an induction motor is stopped due to a dynamic break, fixed magnetic poles are created by the DC voltage applied to the primary side, and current flows through the rotor, which rotates while decelerating, causing a so-called rotating armature. It becomes a type alternator. Statically, this current stops flowing when the rotor stops, but as a transient phenomenon, a delayed current flows according to the L/R time constant of the rotor winding. At this moment, a reverse starting force is generated and the motor rotates in the opposite direction, causing current to flow in the opposite direction again. As this process is repeated, the vehicle gradually decelerates and finally comes to a stop (see Figure 5).

[0004] In particular, induction motors for spindles of spinning machines have low rotor resistance due to their high efficiency characteristics and have long time constants, so this phenomenon is likely to occur. In addition, in the rotation transmission device of a spinning machine, the rotation angle of the spindle is transmitted so that it is 10 to 13 times the rotation angle of the motor shaft, and a small reverse rotation angle of the motor shaft corresponds to a large reverse rotation angle of the spindle. It is what it is.

[0005] If the spindle reverses when stopped, snarl occurs, causing thread breakage when restarting.
In particular, in spinning machines that utilize rings, such as ring spinning machines and ring twisting machines, loosened yarns are more likely to come off the traveler, and yarn breakage is sure to occur when the yarn is restarted. Incidentally, when the direct current voltage applied to the induction motor is low and the braking force is weak, there is a problem that not only does it take time to stop the spindle, but also snarls are likely to occur.

[0006] This invention was made in order to solve such problems in stopping the spindle of a spinning machine driven by an induction motor. It is an object of the present invention to provide a method for stopping a spindle, which does not cause the thread to come off the traveler, and which causes less thread breakage during restart, and an apparatus for carrying out the method.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the method of the present invention involves separating the primary side of an induction motor that drives a spindle from an AC power source, applying a DC voltage to the primary side to excite it, and In this spinning machine spindle stop method that applies dynamic braking to the induction motor, a high DC voltage is first applied to apply strong braking, and after the spindle rotation speed has reached a sufficiently low rotation speed, it is switched to a low DC voltage to apply weak braking. That is.

[0008] As an apparatus for carrying out the method, there is a spinning machine which is connected to an AC power source via an inverter and includes an induction motor that drives a spindle, and a DC voltage application means that applies a DC voltage to the induction motor. The spindle stopping device is provided with a detection means for detecting the rotational speed of the spindle, and a control device for switching the DC voltage applied by the DC voltage applying means between high and low levels based on a signal from the detection means.

[0009]

[Effect] When the spindle is stopped, a high DC voltage is first applied to apply strong braking, so even when the spindle rotation speed is high, there is no snarl (which occurs with weak braking), and it stops quickly. Just before. Immediately before stopping, when the rotational speed of the spindle becomes sufficiently low, the braking is performed by switching to a low DC voltage to provide weak braking, so that the spindle does not reverse during stopping, unlike when a high DC voltage is used. Therefore, there is no occurrence of snarls due to reverse rotation of the spindle, and thread breakage upon restart can be reduced.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a case will be described in which an embodiment of the method of the present invention is applied to a spindle stop device of a spinning machine shown in the drawings. In addition, in the drawings, the same reference numerals are given to the same and corresponding parts.

In FIG. 1, reference numeral 1 denotes a spindle representative of a large number of spindles installed in a spinning machine, and an induction motor M connected to an AC power source via an inverter 2.
is driven by. In addition, 3 is for inverter operation/
This is a stop relay. As shown in FIG. 2, normally the rotation speed of the spindle 1 of a spinning machine is a constant rotation speed
The rotational speed of the induction motor M is controlled to be 0,000 rpm).

[0012] When the yarn wound around the bobbin on the spindle becomes full, the rotation speed R1 of the spindle 1 is reduced to R2 and R3 by a signal from the control device of the spinning machine. The rotation speed just before stopping is approximately 5,000 rpm.
It is.

[0013] Stopping of the spindle 1 is performed by inverter operation and
The stop relay 3 is opened, and then the strong brake switch 7 is closed. By closing the strong brake switch 7, a large current that is converted to a voltage of 30V by the transformer 5 and rectified by the rectifier 6 is passed through the motor M.
A strong braking force is applied to the rotation speed R3 of spindle 1.
to rapidly decelerate (R4).

The rotation speed detected by the rotation detector 11 that detects the rotation speed of the spindle 1 is set to a set value (1,500r).
pm), the strong brake switch opens in response to a command from the control device 12, and the weak brake switch 10 of the weak brake circuit, which includes the transformer 8, the rectifier 9, and the weak brake switch 10, closes.

By closing the weak brake switch 10, a small current converted to a low voltage (10V) by the transformer 8 is passed to the motor M through the rectifier 9. In this way, switching the current to the motor M immediately before stopping prevents the motor M from reversing when the motor M is stopped, leading to gradual deceleration R5 and then to a stop. In addition, as shown in FIG. 5, in the conventional stopping device, when a strong braking force is applied to the motor M at the time of stopping and the rotation speed of the spindle 1 is rapidly reduced, the rotation speed of the spindle 1 is reversed. R5' may occur.

The spindle stopping device shown in FIG. 3 utilizes the DC voltage of the intermediate capacitor 13 in the inverter 2, and dynamic braking of the induction motor M that drives the spindle (not shown) is performed by the transistor 17.
This is done by the braking current flowing through. The brake is switched from strong to weak by detecting the rotation speed of the spindle, and when the rotation speed reaches a set value, the strong brake relay 15 is opened by a signal from a control device (not shown), and the brake is switched to weak brake. This is done by closing relay 16. Note that 14 is a relay for inverter operation/stop.

In the example of FIG. 3, as well as the example of FIG.
When stopping the spindle of a spinning machine, a strong dynamic brake is applied to the induction motor when the spindle speed is high, and after the spindle speed reaches a sufficiently low speed, it is switched to a weaker brake immediately before the spindle stops. This prevents the induction motor from reversing, that is, the spindle from reversing, and thus prevents yarn breakage when restarting the spinning machine.

[0018]

[Effects of the Invention] According to this invention, when the spindle of a spinning machine is stopped, a high DC voltage is first applied to the induction motor that drives the spindle to apply strong braking, and the rotational speed of the spindle is brought to a sufficiently low rotational speed. Afterwards, it switches to a low DC voltage and applies weak braking to stop the induction motor, which prevents the reversal of the spindle, prevents the occurrence of snarls and the traveler coming off as a result, and prevents thread breakage when restarting. can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic illustration of a spindle stop device for a spinning machine for carrying out the method of the present invention.

FIG. 2 is a rough diagram showing changes in spindle rotation speed and motor rotation status of the apparatus shown in FIG. 1;

FIG. 3 is a schematic illustration of another spinning machine spindle stop device for carrying out the method of the present invention.

FIG. 4 is a schematic explanatory diagram of a spindle stop device of a conventional spinning machine.

FIG. 5 is a graph showing changes in spindle rotation speed and motor rotation status of a spindle stop device of a conventional spinning machine.

[Explanation of symbols]

1 Spindle 2 Inverter 3 Inverter operation/stop relays 5, 8
Transformer 6, 9 Rectifier 7 Strong brake switch 10 Weak brake switch 11 Detection device 12 Control device

Claims (2)

[Claims] Claim 1: A spinning machine spindle stopping method in which the primary side of an induction motor that drives a spindle is disconnected from an AC power supply, a DC voltage is applied to the primary side to excite the induction motor, and the induction motor is dynamically braked. A method for stopping a spindle of a spinning machine, characterized in that strong braking is applied by applying a DC voltage, and after the rotational speed of the spindle reaches a sufficiently low rotational speed, switching to a low DC voltage and weak braking is performed. 2. A spindle stop device for a spinning machine comprising an induction motor connected to an AC power source via an inverter to drive a spindle, and a DC voltage applying means to apply a DC voltage to the induction motor. 1. A stopping device for a spinning machine, comprising: a detection means for detecting the detection; and a control device for switching the DC voltage applied by the DC voltage applying means between high and low levels based on a signal from the detection means.