JPS61106334A - Automatic feed controller for motor feeder - Google Patents

Abstract

PURPOSE:To control the feeding amount accurately by performing variable voltage variable frequency control of drive source motor in accordance to preset pattern. CONSTITUTION:A function generator 7a will execute variable voltage variable frequency control of drive source or motor 4 of motor feeder 3 within the range of rated voltage of motor 4 and resonant frequency of motor feeder 3. In other word, in the range lower than the resonant frequency of motor feeder 3, the voltage V is controlled while maintaining the frequency F constant while in the range higher than rated voltage of motor 4, the frequency F is controlled while maintaining the voltage V constant thus to control the feeding amount W. While VVVF unit 7 will perform control operation in accordance to the feedback control signal from a signal generator and the control signal from the function generator 7a. Consequently, it will control in accordance to the feeding amount of material 2 at anytime.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides an electric motor for cutting out powdery material such as ore from the lower end of a storage tank such as a hopper, silo, or bin bunker for storing powdery material such as ore. This relates to a control device for the amount of feeder cut out per unit time, and more specifically, it aims to automatically achieve control over the cut-out of powder and granular materials using an electric feeder with a wider control range and higher precision. be.

[Conventional technology]

BACKGROUND OF THE INVENTION Controlling the extraction of raw materials from storage tanks that store granular raw materials such as ores is extremely important in terms of downstream processes and quality control.

There is a strong demand for automation and wide control range in addition to accuracy in controlling the cutting out of raw materials.

In the conventional cutting device, as shown in Fig. 5, an electric feeder 3 for cutting is placed in the bottom 1 of a storage tank 1, and a motor 4 for driving the electric feeder 3 is connected to the output of a slider bag, which is a variable voltage transformer. The drive is controlled by.

A heald conveyor 5 is arranged directly below the electric feeder 3, and is configured to generally transport the raw material 2 cut out by the electric feeder 3 to a destination.

The conventional control device shown in FIG.
The voltage applied to the motor 4 is changed by the operation of
The amount of cutout is adjusted.

In general, the amount of raw material 2 cut out by the electric feeder 3 is proportional to the general speed of transport, and the general speed of transport is proportional to the radiation velocity x radiation angle from the storage (al), and the speed of these feeders is proportional to the amplitude x frequency. It is said to be proportional.

[Problem that the invention seeks to solve]

In the conventional example shown in FIG. 5, the voltage applied to the motor 4 is changed by operating the slider bag. The method is to change the M-axis speed of the motor 4 using so-called primary voltage control to adjust the amount of raw material 2 cut out by the electric feeder 3, but this conventional method has the following problems. .

That is, firstly, since the change in the rotation speed of the motor 4 due to the primary voltage control is slight, the control range for cutting out the raw material 2 by the electric feeder 3 is extremely narrow; and secondly, the slider Because it uses a bag, there are many breakdowns due to wear in the U moving part, especially of this Slide Duck 6.

The third problem is that the cutting amount must be reduced.
.

Judging by the measurement results from the flow-side conveyance measuring device, the slider bag is operated directly or remotely via the pilot motor, thereby appropriately adjusting the primary voltage of the motor 4, that is, the cutting amount. This is because it is a manual level method.

Adjustment is time-consuming, control accuracy is poor, and the fourth problem is
Even if the amount is adjusted to a certain amount using the method described above, the amount of raw material 2, type 2, and particle size.

Since the amount of cutout changes due to changes in the raw material 2 in the storage ii, there are problems such as the need to constantly monitor the measured value on the conveyance meter and finely adjust the slide 6 accordingly. Ta.

For example, the change in the rotational speed of the motor 4 due to the primary voltage control is very small, as shown by the dotted line curve E in FIG.
Accordingly, the cutout 1w does not change much.

[Means for solving problems]

The present invention has been devised to solve the problems and drawbacks of the above-mentioned conventional example. It is configured to allow frequency control.

Three aspects of the present invention will be described below with reference to drawings showing one embodiment thereof.

The automatic cutting control device for an electric feeder according to the present invention includes:
An electric feeder 3 is provided at the lower end of the storage tank 1 and vibrates by an electric drive to cut out the raw material 2 which is a particulate material in the storage tank 1.
a motor 4 that electrically drives the electric feeder 3; a cutting amount setting device that sets a target cutting amount; a measuring device that measures the amount of raw material 2 cut out by the electric feeder 3; a signal generator that calculates the deviation between the measured weighing signal and the setting signal set by the cutting amount setting device and outputs this deviation value as a feedback control signal; The upper limit of the voltage of the power supplied to the motor 4 is regulated according to the rated value of the motor 4, and the lower limit of the frequency of the power supplied to the electric feeder 3 is regulated according to the resonance frequency of the electric feeder 3, thereby controlling the voltage and frequency of the power supplied to the motor 4. The variable voltage/variable frequency device 7 is equipped with a function generator 7a'' for proportional control.

Generally in variable voltage variable frequency control.

In order to prevent magnetic saturation when the frequency F changes, the voltage V is also changed proportionally, and control is performed such that V/F=constant; Instead of control, DJ variable voltage variable frequency control is performed according to the relationship between voltage V and frequency F as shown in FIG.

In Figure 2, between point a and point a on curve A, i
i1 Same as usual variable voltage variable frequency control.

V/F = constant control, but 9 below 1 point a
Control is carried out by changing only the voltage V while keeping the frequency F constant. For 1 point or more, the voltage V is changed to -.
Frequency 1 while keeping it constant? It is controlled by changing the flow rate.

The reason why only the voltage V is changed and the frequency F is kept constant below point a is that if the electric feeder 3 reaches a frequency below point a, it will deviate from the resonant frequency and cause abnormal vibration, resulting in mechanical damage g. This is because electric feeder 3 is connected to point 3.
Therefore, below point a, the cutout iW is controlled only by changing the voltage .

Also, if you keep the voltage V constant by changing only the 0 frequency F at more than 1 point, the voltage value at 3 points is the motor 4.
This is the maximum rated voltage of F, so if a voltage higher than this voltage is applied to the motor 4, dielectric breakdown will occur in the motor 4. The amount W is controlled.

The signal generator 17 calculates the deviation between the setting signal from the cutting amount setting device and the measurement signal from the measuring device, and outputs this deviation value to the variable voltage variable frequency device 7 as a feedback control signal with polarity. Therefore, it is basically a type of main controller.

[Effect]

That is, the function generator 7a used in the device of the present invention is as follows.

The motor 4, which is the drive source of the electric feeder 3, is controlled with variable voltage and frequency in a range between the rated voltage of the motor 4 and the resonance frequency of the electric feeder 3, and the range is equal to or less than the resonance WJ'eL number of the electric feeder 3. In this case, the voltage ■ is varied and controlled while keeping the frequency F constant, and in the range above the rated voltage of the motor 4, the frequency F is varied and controlled while keeping the voltage ■ constant to control the cut-out 1W. .

Therefore, the amount W of raw material 2 cut out by the electric feeder 3
The change in becomes like the curve shown in the solid line diagram in Figure 6,
Compared to the conventional curve E showing a change in 1w of cutting, the control range can be made much larger.

The variable voltage variable frequency device 7 also operates according to the feedback control signal from the signal generator and generates a function D7a.
Since the control operation is performed according to the control signal issued by the machine, the amount of raw material 2 to be cut out is always controlled according to the star of the raw material 2 that is cut out, and therefore the amount of raw material 2 to be cut out is always equal to the cutting base set by the cutting amount setting device. Every time I'm confronted with this.

〔Example〕

FIG. 1 shows an electric circuit configuration diagram showing one embodiment of the device of the present invention, and the feedback control signal outputted from the signal generator 17 is an analog signal.

In FIG. 1, the 9-cut setting device consists of a setting board 8 mainly composed of a low-resistance device, and by adjusting the volume of this setting board 8, a setting signal that is the target cutting amount is set. Ru.

The weighing device is constituted by a transported quantity measuring device 9 installed in the middle of the belt conveyor 5.

A signal generator that calculates the deviation between the setting signal from the setting board 8 and the weighing signal from the transported quantity measuring device 9 includes an adder 10 that adds the setting signal and the weighing signal;
A dead hand processing 11 performs dead band processing on the signal from 0, an amplifier 12 amplifies the output of this dead band processing 11, and a clock signal generator 15 to a counter 14 according to the polarity of the output from this amplifier 12. a relay 13 that sets the input direction of the pulse signal; a counter 14 that counts the number of pulses from the clock signal generator 15 according to the magnitude of the output of the amplifier 12;
A D/A converter 16 converts the digital value output of 4 into an analog value and outputs it as a feedback control signal.
It is composed of.

In other words, the setting signal and the weighing signal are added! 510, and the difference between the two is filtered both temporally and numerically in dead band processing 11.

In other words, with a certain time delay, G 11+'
When a difference of 19 is produced, the difference is amplified by the amplifier 12 and output.

The counter 14 counts the pulse signal from the clock signal generator 15, and counts in the direction of the amplifier that is 'MIJ<' by the relay 13 or in the down direction depending on the polarity of the output from the amplifier 12.
If the positive difference is large, the counter will move in the direction of lowering it, and if the negative difference is large, it will not move in the direction of raising the counter.

The foot-eight system tart (t
Motor 4 by variable electrician variable frequency device 7 by 'r'
We will explain the start/stop control of.

First, as shown in FIG. 4, the activation rapidly accelerates with respect to the horizontal time axis until it reaches the point in FIGS. 2 and 3.

That is, it is clear from the voltage characteristic curve of the motor 4 and the frequency characteristic curve of the electric feeder 3 in FIG.
/F- The voltage V is raised to the maximum rated voltage of the motor 4 and the motor 4 is driven when certain conditions are met.

Turn on motor 4 like this! After operating for a certain period of time, the motor 4 is controlled according to the feedbank control signal described above.

The reason for this is that the electric feeder 3 is not initially in the imaging state in the resonant frequency range where the highest voltage 1, for example 60+12, is applied, but other voltages and frequencies F cause abnormal vibrations. Feedback l control is performed based on the measured value of the quantity measuring device 9, so there will be a one-hour delay.What is this time delay? In order to be able to compensate for the loss of time, a large amount of cutout is initially used.

On the other hand, when stopping the motor, the power is not suddenly turned off, but the value of the feedback control signal is gradually reduced to bring about a gradual stop, as shown in operating curve 2 in FIG.

This is because if the power is suddenly turned off, the electric feeder 3 will continue coasting after the power is turned off, and the cutting of the raw material 2 will not stop smoothly, so the V/F is forcibly lowered to stop it.

〔Effect of the invention〕

As is clear from the above description, the automatic cut-out control device according to the present invention can control the amount of raw material cut out from the storage tank by the electric feeder in a very wide range, and has high reliability of the device. It exhibits many excellent effects, such as being able to automatically perform cut-out control regardless of the type of raw material, 9 particle sizes, and changes in the raw material in the storage tank.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing an example of the electrical circuit configuration of a control device according to the present invention. FIG. 2 is a diagram showing the relationship between the voltage and frequency of the control power signal. FIG. 3 is a diagram showing the relationship between the feedback control signal and the Dengetsu 35 frequency. FIG. 4 shows an example of start/stop control using a variable voltage variable frequency device with feedback il+! I? FIG. 4 is a diagram illustrating an example of a changing state of an il signal. - Fig. 5 shows an example of a conventional control device of this type. FIG. FIG. 6 is a characteristic diagram showing the relationship between voltage 0 frequency and cutting amount. Explanation of symbols 1; storage tank; 2; raw material; 3; electric feeder; 4; motor;
5; Belt conveyor, 7; Variable voltage variable frequency device, 7
a; Function generator; 8; Setting board. 9; Transportation amount meter; 10; Adder; Engineering 1; Defed band processing; 12; Amplifier; 13; Relay; 14; Counter. 15; Cronk signal generator, 16i D/A converter. 17; Signal generator. Applicant: Kawasaki Steel Co., Ltd. Table quiz %'/Ji・V纺 PR- Zubrif Nasuzu 2bu) Nasu 〆淀

Claims (1)

[Claims] An electric feeder provided at the lower end of the storage tank and vibrated by electric drive to cut out the powder and granular material in the storage tank, a motor for electrically driving the electric feeder, a cutting amount setting device for setting a target cutting amount, and the electric feeder A measuring device that measures the amount of the cut-out powder and granules, calculates the deviation between the measuring signal detected by the measuring device and the setting signal set by the cut-out amount setting device, and sends the deviation value to a feedback control signal. a signal generator that outputs a signal as a signal generator, and according to a feedback signal from the signal generator, the upper limit value of the voltage of the power supplied to the motor is regulated according to the rated value of the motor, and the lower limit value of the frequency of the supplied power is regulated to the electric feeder. and a variable voltage variable frequency device that proportionally controls the voltage and frequency of power supplied to the motor by regulating it according to the resonance frequency of the motor.