JPS6251485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electromagnet device, and particularly to a control device that can reduce whirring noise while reducing power consumption.

In general, single-phase AC electromagnets have the advantage of being smaller, lighter, and faster in operation than DC electromagnets, but they have the disadvantage of generating noise or whirring noise due to alternating magnetic flux. Therefore, the AC electromagnet device is constructed as shown in FIG.

FIG. 1 shows a general single-phase AC electromagnet device, with the left half being a front view and the right half being a sectional view. In the figure, 1 is a fixed iron core made of a stratified iron core, 2 is an excitation coil wound around the center pole 3 of the fixed iron core 1, 4 is a movable iron core made of a stratified iron core,
At the magnetic pole head portion of the 5,6 fixed iron core 1, a shade removal coil 7 is attached to the magnetic pole head portion 5.

A single-phase AC electromagnet device having such a configuration has a magnetic flux φ _s passing through the magnetic pole head 5 surrounded by the shaded coil 7 and a magnetic flux φ _u passing through the magnetic pole head 6 not surrounded by the shaded coil 7. By creating a phase difference between the fixed core 1 and the movable core 4, the minimum value of the combined attraction force that attracts the movable core 4 is always greater than the external repulsive force of the movable core 4, thereby eliminating noise in the alternating magnetic flux. .

Regarding the humming noise, since the attractive force includes a pulsating component with a frequency twice that of the power supply, the difference between the maximum and minimum values of this pulsating component causes the strength of the compressive stress due to the electromagnetic attractive force within the iron core. This generates a whining sound, which generally occurs with varying degrees of intensity.

Next, the results of simulation calculations performed by an electronic computer will be explained as an example.

Figure 2 is a simulation of the characteristics of a general AC electromagnet device in excessive attraction and steady attraction states as shown in Figure 1. In the figure, W ₁ is the voltage waveform of the AC power supply, W ₂ and W ₃ are the magnetic pole heads of the iron core. The magnetic flux waveform passing through,
W ₄ shows the composite magnetic flux waveform passing through the iron core, W ₅ shows the current waveform of the excitation coil, W ₆ shows the current waveform of the shaded coil, W ₇ shows the waveform of the total attractive force, and W ₈ shows the external repulsive force. However, the horizontal axis indicates time. In this general AC electromagnet device, as can be seen from Figure 2, the minimum value W _7nio of the attractive force W ₇ is always equal to the external repulsive force
Since it is larger than W ₈ , no noise is generated.
However, since the difference between the maximum value W _7nax and the minimum value W _7nio of the attraction force W ₇ is increasing, the strength of compressive stress due to the electromagnetic attraction force is generated within the iron core, and a whirring sound is generated. If this growling noise is loud, it will cause discomfort. Note that _W9 indicates the displacement (stroke) of the movable iron core of the electromagnetic drive device. In addition, the power supply frequency in FIG. 6 shows the case of 60Hz240V (maximum value) voltage. On the other hand, pure DC electromagnet devices do not generate whirring noise because the attraction force does not include a pulsating component, but when compared at the same voltage value, after attraction,
As in the case of alternating current, a constant current flows without alternation, and the current is determined only by the resistance of the excitation (electromagnetic) coil, so if we assume that the AC electromagnet device, iron core, and excitation coil are the same, A larger current flows than in an AC electromagnet device, and the copper loss in the coil increases, resulting in the coil burning out if used for a long time. Therefore, in DC electromagnet devices, the resistance value of the coil is increased, but in this case, the current becomes smaller and the magnetomotive force becomes smaller, so the number of turns of the coil must be increased, making the coil larger and compared to AC electromagnet devices. This has the disadvantage that the overall size of the device increases.

As a way to prevent such devices from increasing in size, as shown in Figure 3, the excitation (electromagnetic) coil 2
A saving resistor 7 is connected in series with the saving resistor 7, and a normally-closed circuit contact 8 is inserted in parallel with this saving resistor 7. When the normally-closed circuit contact is turned on, DC voltage is applied to the excitation (electromagnetic) coil 2, and after turning on. By opening the normally closed contact 8 and applying it to the excitation (electromagnetic) coil 2 via the saving resistor 7, the current is suppressed and the excitation (electromagnetic) coil 2 is
A method has been adopted to reduce the copper loss of the excitation (electromagnetic) coil 2 and prevent burnout of the excitation (electromagnetic) coil 2. This method requires the use of normally closed contacts and economical resistors, and requires reliable contact operation and contact. It also has the disadvantage that the total power consumption remains unchanged. In addition, 9 is a DC power supply, and 10 is a switch for turning on.

The present invention uses an electronic control method different from the conventional phase control method to reduce the power consumption for exciting the electromagnetic device and reduce whirring noise compared to the conventional method and compared to the phase control method. It is an object of the present invention to provide a control device for an electromagnet device that can improve the performance.

Next, the principle of the present invention will be explained with reference to the case where an AC power source is used.

As shown in FIGS. 4 and 5, the AC power supply 11 is full-wave rectified by a rectifier 12 and converted into a DC voltage (full-wave rectification) as shown in FIG.
Switches SW ₁₀ and SW ₂₀ operate simultaneously to switch terminals 13A-13B for a certain period of time _.
At the same time as disconnecting from the power supply 11 by
The voltage supply to the electromagnetic device 14 is made zero by shorting the terminals 13A-13B with SW _20. Next, the short-circuiting of the terminals 13A-13B is opened with SW ₂₀ for a certain period of time, and at the same time, the switch SW ₁₀ is opened. By repeating the operation of supplying voltage to the electromagnetic device 14 by using the above steps, the voltage is supplied as shown in FIG. 5b. Switches SW ₁₀ and SW ₂₀ function as follows. Cutting off the power supply using switch SW ₁₀ limits the increase in current due to full-wave rectification and suppresses the temperature rise due to copper loss in the coil. Furthermore, if the suction power is sufficiently strong, it is possible to save power consumption. Terminal 13A with switch SW ₂₀
A short circuit of -13B causes the electromagnetic device 14 to convert the accumulated electromagnetic energy into electrical energy, generate an attractive force, and maintain the attractive force even when the electrical energy supply from the power supply is in a zero state. Let it happen. In other words, it acts like a flywheel of suction force. In some cases, terminal 13A-13
B may be left open without being short-circuited.

Next, an example of a simulation calculation result using an electronic computer will be explained.

Fig. 6 shows an AC electromagnet device having the characteristics shown in Fig. 2, based on the principle shown in Fig. 4 according to the present invention, using an AC power source of the same frequency and voltage as Fig. 2, and using the zero point of the voltage as a reference every half wave. and turn the switch as shown in Figure 7.
The simulation is shown when switching SW ₁₀ -SW ₂₀ and switches SW ₁₁ -SW ₂₁ are repeatedly switched from energizing for 0.1 msec to no voltage for 1.6 msec at the same time.
Comparing FIG. 2 and FIG. 6, it can be seen that according to the principle of the present invention, the characteristics of the attraction force W ₇ , that is, the difference between the maximum value W _7nax and the minimum value W _7nio of the attraction force, are significantly smaller than in the conventional case. You can see that In other words, it can be seen that the whining noise is significantly reduced. Also, the maximum suction force _W7nio has increased significantly compared to the conventional model. Figure 8 shows an AC electromagnet device similar to that shown in Figure 2 using an AC power source with the same frequency and voltage as in Figure 2, using the conventional thyristor phase control method (7 msec no-voltage,
A simulation is shown when the device is operated with 1 msec current supply). Comparing FIG. 6 and FIG. 8, the difference between the maximum value W _7nax and the minimum value W _7nio of the attraction force according to the present invention is the same as the difference between the maximum value W _7nax and the minimum value W _7nio of the attraction force of the conventional thyristor phase control method. It can be seen that the difference is less than 1/2 of the difference. As mentioned above, the whining noise of the iron core is proportional to the difference between the maximum value and the minimum value of the suction force, so the present invention can reduce the whining noise to less than half compared to the conventional phase control method. It can be said that the performance is greatly improved. FIG. 9 shows a block diagram of a humming noise reduction device for an AC electromagnet device according to the present invention, in which 10 is a sine wave AC power supply, 102 is a general AC electromagnet device, and 1
03 is a rectifier, 104 is an electronic control device for reducing humming noise and power consumption, and after a certain appropriate time T ₀ after turning on the switch SW ₀ , as shown in Fig. 10, the power supply voltage is set to zero. So, every half wave,
T ₁ hour energization → T ₂ hours no voltage is repeated, T ₃ hours no energization, T ₁ hour energization → T ₂ hours no energization is repeated, and T ₀ , T ₁ , T ₂ , and T ₃ can be adjusted freely. The functions of the switches shown in Figs. 3 and 4 are constructed with electronic circuits to enable this.

Note that the times T ₁ and T ₂ do not necessarily have to be based on the zero point of the voltage, and may be energized or non-energized operations using pulse oscillation, but the time T ₃ is based on the voltage waveform. From the simulation results, it is desirable to have a time chart that is symmetrical about the point of the maximum value. Furthermore, when the power source is DC, the rectifier 103 may be omitted and T ₁ , T ₂ , and T ₃ may be adjusted. Figure 11 shows an AC electromagnet device with the characteristics shown in Figure 2, using an AC power source with the same frequency and voltage as in Figure 2.
0.1msec energization per half wave → 1msec no voltage → 0.1m
sec energization → 3.2msec no voltage → 0.1msec energization → 1m
sec no voltage → 0.1msec energization → 1msec no voltage → 0.1
The simulation is shown when msec energization is repeated periodically. The difference between the maximum value W _7nax and the minimum value W _7nio of the attractive force W ₇ is almost the same as that in Fig. 6, but the maximum value W _70nax of the high frequency component is and minimum value W ₇₀
It can be said that the difference in _nio has become slightly smaller, and therefore the humming sound of high frequency components has become smaller.

Fig. 12 shows an AC electromagnet device with the characteristics shown in Fig. 2 that is energized for 0.1 msec every half wave with an AC power supply of the same frequency and different voltage (340V (maximum value)) as in Fig. 2.
This is a simulation of periodically repeating 1.6msec no voltage → 0.1msec energization → 3.3msec no voltage → 0.1msec energization → 1.6msec no voltage → 0.1msec energization → 1.4msec no voltage, but it is a normal adsorption state. Average value of force and copper loss of the coil (power consumption W ₁₀ )
are also almost the same. From this, as mentioned above, by adjusting T ₁ , T ₂ , and T ₃ in Figure 10, the applicable range of using the same electromagnetic coil and different power supply voltages can be expanded (for example, from AC200 to
Enables sharing of excitation (electromagnetic) coils up to 400V. ).

Figure 13 shows the T ₀ time in Figure 10 from 25 msec.
16.6 msec, but otherwise the simulation is shown under the same conditions as in Fig. 12. Comparing Fig. 12 and Fig. 13, the movable core 4 of the electromagnet device
It can be seen that the appearance of the attraction force W ₇ after the time at the point of displacement W ₉₀ when is attracted to the fixed iron core 1 is quite different. That is, in FIG. 12,
The suction force after the movable iron core 4 is attracted increases rapidly, but in FIG. 13, after the suction, the suction force decreases once and then gradually increases to a constant value.
This is because, in FIG. 12, the impact when the movable core 4 and the fixed core 1 are attracted is severe, whereas in FIG. 13, the impact is mild compared to that in FIG. This reduces wear on the iron core due to 10,000 cycles), and the impact of the closing operation on devices driven by this electromagnetic device (e.g. electromagnetic contactors, relays) is small.For example, when used in electromagnetic contactors, the contact This provides performance advantages such as less bouncing and therefore less wear due to contact arcing and longer electrical life.

In this way, by adjusting the time T ₀ in FIG. 10, it is possible to reduce the impact load when the movable iron core 4 and the fixed iron core 1 are attracted to each other.

As explained above, the present invention has the following advantages.

By reducing the difference between the maximum value and the minimum value of the suction force, the humming noise can be reduced.

Power consumption during steady adsorption can be saved.

The applicable range of power supply (input) voltage ratings can be expanded without changing the excitation (electromagnetic) coil.

The impact during adsorption can be reduced.

Applicable to both AC and DC power sources.

Because it converts to DC, the shaded coil of the conventional AC electromagnet device is abolished.

Due to DC conversion, unlike conventional AC electromagnet devices, no alternating magnetic flux passes through the iron core, and therefore no eddy current is generated, so there is no iron loss. The core can be made of cast steel, formed steel, etc.

Note that the control device of the present invention may be separately attached to the electromagnet device, or may be built in in combination with the electromagnet device.

FIG. 14 shows a specific embodiment using the electronic control device 104 shown in FIG.
This will be explained based on the diagram.

In FIG. 14, 11 is an AC power supply, 12 is a rectifier, 14 is an electromagnetic device, D1 and D2 are diodes, R1 to R5 are resistors, TR is a transistor,
IC1 is a comparison amplifier, IC2 is an AND element (hereinafter referred to as AND element), IC3 is an OR element (hereinafter referred to as OR element), and IC4 is a NOT element (hereinafter referred to as NOT element). Note that 400 is a constant voltage circuit, 401 is an oscillation circuit, and 402 is a delay circuit.

In this configuration, when the AC power source 11 is applied to the rectifier 12 (Fig. 15a)
Reference) Resistor R1 connected to the output of the rectifier 12
Full-wave rectified waveform output from pressure circuit R2
V ₂ (see FIG. 15c) is input to the comparison amplifier IC1. This full wave rectified waveform V ₂ is created by resistor R3 and R
The reference voltage V ₃ (first
waveform V ₄ (see Figure 5 b) and is amplified.
(see Figure d) is output from the comparison amplifier IC1.
Since the AND element IC2 outputs the output V ₅ (see FIG. 15e) of the oscillation circuit 401 only when the output of the comparison amplifier IC1 is at a high potential, the waveform V ₆ (first
(see Figure 5 f) is obtained. Also note element IC4
outputs a high potential for a time T ₀ determined by the delay circuit 402 after the AC power supply 11 is applied, so that the transistor TR is in a conductive state for the time T ₀ and the electromagnetic device 14 is excited. . Since the time T ₀ is set longer than the time necessary for the electromagnetic device 14 to perform suction, the suction operation is completed after the time T ₀ . Next, after time _T0 , the transistor TR repeats conduction and cutoff, that is, switching, in accordance with the output waveform _V6 of the AND element IC2. If the transistor TR conducts here,
Needless to say, current flows through the electromagnet device 14, but when the transistor TR is cut off, the coil energy of the electromagnet device 14 is circulated by the diode D1, so the electromagnet device 1
4, the current continues to flow. That is, since the coil current does not become an intermittent current, the attraction state is maintained.

It goes without saying that the time _T3 during which the peak value of the AC power supply 11 is cut can be appropriately controlled by changing the voltage division ratio of the resistors R3 and R4. Further, by appropriately setting the oscillation circuit 401, the conduction time _T1 and the cutoff time _T2 can be varied, so it goes without saying that the settings can be made to minimize beats and energy consumption.

Further, in this embodiment, the oscillation circuit has been described as an asynchronous type, but it goes without saying that if the oscillation circuit is synchronized with the AC power supply, continuity near the zero point can be ensured, so that the effects of the present invention can be expected to be even more effective. do not have. In addition, the time _T3 for cutting the peak value of the AC power supply is explained in this embodiment as cutting when the voltage exceeds a certain level, but the same effect can be obtained by appropriately changing the voltage at which cutting starts and the voltage at which cutting ends. Needless to say, this effect can be obtained.

In addition, when the AC power supply 11 becomes a DC power supply, the peak value cut _T3 cannot be set, but the oscillation circuit 4
It goes without saying that similar effects can be obtained by appropriately setting 01. In some cases, a capacitor may be used instead of the diode D1, or the diode D1 may be omitted. Furthermore, it is also possible to use a chopper composed of a thyristor instead of the transistor TR. Incidentally, FIG. 15 is a time chart of each output of this embodiment.

As described above, according to the present invention, it is possible to reduce whirring noise while reducing the power consumption for exciting the electromagnet device, and it is possible to configure the device without increasing its size. Various beneficial effects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the schematic configuration of a general single-phase AC electromagnet device, Fig. 2 is a waveform diagram showing the waveforms of various parts when a general AC electromagnet device is being supplied with power, and Fig. 3 is a general Figure 4 is a circuit configuration diagram for explaining the principle of the present invention, Figures 5 a and b are waveform diagrams for explaining Figure 4, and Figure 6 is a connection diagram showing the circuit configuration of the DC electromagnet device. The figure is a waveform diagram showing the waveforms of various parts during operation of the control device in one embodiment of the present invention, FIG. 7 is a circuit configuration diagram showing one embodiment of the present invention, and FIG. 8 is a waveform diagram in the conventional thyristor phase control system. A waveform diagram showing the waveforms of each part, FIG. 9 is a block diagram showing the connection relationship when the present invention is applied to a general AC electromagnet device, and FIG. 10 is a waveform diagram for explaining the operation of FIG. 9. 11 to 13 are waveform diagrams showing waveforms of various parts in other embodiments of the present invention, FIG. 14 is a circuit connection diagram showing a specific embodiment in which the present invention is configured with an electronic circuit, and FIG. 15 The figure is a waveform diagram showing waveforms of various parts for explaining the operation of the circuit of FIG. 14. In the figure, 1 is a fixed core, 2 is an excitation (electromagnetic) coil, 4 is a movable core, 11, 101 is an AC power supply, 1
2, 103 is a rectifier, 14, 102 is an electromagnet device, SW ₀ , SW ₁₀ , SW ₂₀ , SW ₁₁ , SW ₂₁ are switches, and 103 is an electronic control device. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A control device provided with a switch that is interposed between an excitation coil of an electromagnet device and an AC power supply and controls the supply of power to the excitation coil so that it periodically repeats an energized state and a de-energized state. The electromagnetic device is characterized in that the switch is switched so as to periodically repeat the energized state and the non-energized state at least twice every half wave of the full-wave rectified output of the AC power source. Control device. 2 Repeat the energized state and de-energized state at least three times or more, and switch the switch so that the time in the de-energized state is longer than the time in the de-energized state during the other repetitions in the middle of the half wave of the output. A control device for an electromagnet device according to claim 1, characterized in that: 3 Targeting the time when the repetition of the energized state and de-energized state for each half wave reaches the maximum voltage value, set the above switch so that the time of the de-energized state is larger than the time of the de-energized state of other repetitions. A control device for an electromagnet device according to claim 1 or 2, characterized in that the control device switches the electromagnet device. 4. A control device for an electromagnet device according to claim 1, wherein the time duration between the energized state and the non-energized state is adjusted.