JPH0429509A - Vibration suppressing enclosed switchboard - Google Patents

Abstract

PURPOSE:To suppress vibration energy actively and to prevent vibration of an enclosed switchboard by disposing a drive unit generating a reverse phase vibrating force between the lower section of an enclosing box and the installing section of floor face. CONSTITUTION:Upon occurrence of vibration, vibration sensors 5a, 5b mounted on an enclosed switchboard detect vibration on the switchboard side and the installing section side and provides the detected vibration to a frequency analyzer 71. The frequency analyzer 71 analyzes phase angles, frequencies and amplitudes on the switchboard side and the installing section side which are then fed to a logic operating unit 72. The logic operating unit 72 operates the differential vibration between the switchboard side and the installing section side and then operates a pressure supply unit 10. Consequently, a drive unit 6 drives a piston in a cylinder vertically to produce a vibrating force having reverse phase to that of the vibrating force of the enclosed switchboard. The drive unit 6 operates actively to deal with vertical, lateral, longitudinal and combined vibration of the enclosed box 1.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a vibration damping structure for a vibration-resistant closed switchboard.

(Prior Art) As is well known, a closed switchboard houses electrical equipment such as main circuit breakers, transformers, or control circuit equipment such as auxiliary relays, meters, and electric wires in a closed box.

By the way, as earthquake-resistant closed switchboards, there is an earthquake-resistant closed switchboard that has a rigid structure and has a natural frequency of 20 h or more. In such an earthquake-resistant closed switchboard, as shown in FIG. 6, a closed box 1 is welded to a strong box frame 2 made of angle iron, U-shaped steel, iron plate, etc., and electrical equipment 3 is housed therein. The seismic closed switchboard with rigid structure has a geological frequency (0.5Hz -10
Hz), it has a natural frequency of 20 Hz or more, so it does not resonate with earthquakes, and the closed box has sufficient strength, so it has a structure that can sufficiently withstand earthquakes.

(Problems to be Solved by the Invention) However, since the earthquake-resistant closed switchboard has a rigid structure, the vibration energy of the earthquake may be directly transmitted to the electrical equipment housed therein, causing an adverse effect. Furthermore, in recent years, computers and the like have been introduced into electrical equipment to make it electronic, so even low vibration energies such as those caused by small to medium earthquakes can cause failures, malfunctions, or loss of functionality. As described above, conventional earthquake-resistant closed switchboards have a rigid structure that avoids resonance with earthquakes, but they cannot suppress vibration energy, which has the disadvantage of adversely affecting the electrical equipment housed therein.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent vibration-damping closed switchboards by adding a device that actively suppresses the vibration energy transmitted to the closed switchboards during an earthquake. Our goal is to provide the following.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a closed power distribution board in which electrical equipment is housed in a closed box, in which a sensor detects horizontal vibration and vertical vibration of the closed box. and a control device that converts the output from the sensor into vertical vibration and generates a frequency with the same amplitude and opposite phase with respect to the amplitude and frequency of the vibration based on the calculation result,
The present invention is characterized in that a drive device is provided that vibrates the closed box in the vertical direction in accordance with the output of the control device.

(Function) Let Wl be the height H1 width of the closed switchboard, W2 be the depth, m be the weight, and let k be the spring constant and C be the damping constant at any position of the closed switchboard.

The vibration force applied to the closed switchboard is F. sinωt(F.

: amplitude of excitation force ω: frequency t: time), the following equation of motion holds true.

mx+c x+kx=Fosinωt-■Here, X:
Amount of change λ, x: Derivative of function x (t) with respect to time t When the above equation of motion is solved for steady vibration X, the following equation (2) is obtained.

x = As1n(ωt −'l') − (2) Here, A is the amplitude of forced vibration, which is expressed by b) It is expressed as:

From this, the values of the amplitude A and the phase angle delay T of the forced vibration at an arbitrary position of the closed switchboard are determined.

Therefore, if the amplitude is replaced by the amplitude A in the vertical direction at the installation position, in the case of horizontal vibration, as shown in Figure 4, the height of an arbitrary position and the amplitude A of the forced vibration. The following formula 0 is obtained.

In the case of vertical vibration, the amplitude of forced vibration A =
A.

Therefore, the amplitude Ae and the frequency sin (ωt−'f
The vertical vibration force generated at the installation position by -Alsin(ωt-
1), and by applying this vibration force to the closed box, the vibration force F is applied to the closed switchboard. It becomes a force to suppress sinωt.

From this, with respect to the vibration force applied to the closed switchboard, it is sufficient to create a vibration force that is in the opposite phase to the vibration force that the closed switchboard receives.

Based on the above concept, the present invention provides a drive device that generates vibration forces in opposite phases between the lower part of the closed box and the installation part on the floor, thereby actively suppressing vibration energy. The vibration of the closed switchboard can be effectively prevented.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention, and FIG. 2 is a detailed sectional view of portion A in FIG. 1.

As shown in FIG. 1, the vibration-damping closed switchboard is fixed via a drive device 6 between the bottom of the closed box 1 and the installation section 4 on the floor. As shown in FIG. 2, this drive device 6 is composed of a piston 8 directly connected to the bottom surface of the closed box 1, a cylinder 9 surrounding it, and a position sensor 12. A vertical vibration force is created by sucking and discharging a medium 13 such as oil or air through a control pipe 11a using a pressure supply device 10 (see FIG. 1) to drive the piston 8. At this time, the position sensor 12 reads the scale 88 and the like attached to the piston 8, and feeds back the value to the control device 7 to adjust the amplitude of the piston 8.

On the other hand, the closed box 1 is provided with switchboard-side vibration sensors 5b at necessary locations in the upper, middle, and lower parts of the left and right sides.
Further, an installation part-side vibration sensor 5a is also provided on the installation part 4 on the floor. These vibration sensors 5a.

5b senses the vibrations of the floor surface and the vibrations of the top and bottom, left and right sides 9 of the closed box 1, and outputs them to the control device w7 via the control line 11b. As shown in FIG. 3, the control device 7 is composed of a frequency analyzer 71 and a logic operation device 72, and based on the output signals from each vibration sensor 5a, 5b, the frequency analysis device 71 and the logic operation bag [72 The amplitude A of forced vibration and the phase angle delay r can be calculated by:

That is, the amplitude A and the phase angle delay r of one forced vibration can be determined by the spring constant of the closed switchboard and the damping constant C9 weight m. However, the closed switchboard has various closed boxes 1, and the electrical equipment stored therein is also not constant.

The c and m values also become inconsistent, making it extremely complicated to determine the amplitude A of the forced vibration.

In contrast, according to this embodiment, when vibration occurs, the vibration sensors 5a and 5b installed at predetermined positions on the closed switchboard
detects vibrations on the switchboard side and the installation part side and outputs them to the frequency analyzer 71. The frequency analyzer 71 has nine phase angle frequencies on the power distribution board side and the installation side.

Each amplitude is analyzed and output to the logic operation bag w72.

The logical operation device 72 calculates the difference between the vibrations on the switchboard side and the installation part side, and based on the calculation result, the pressure supply device lO
make it work. As a result, the driving device 6 causes the medium 13 in the cylinder 9 to be sucked and discharged, and the piston 8 is driven in the vertical direction, creating a vibration force that is in the opposite phase to the vibration force of the closed switchboard.

This drive device 6 is installed at four corners of the closed switchboard, or more if necessary, and is actively driven to move the top, bottom, left and right sides of the closed box 1.

It can respond to vibrations in the front and rear directions and their combined directions.

The drive device 6 of the above-described embodiment includes a piston 8 and a cylinder 9.
1 position sensor 12, etc., and as shown in FIG.
．． Ball screw 1 attached to the shaft of servo motor 14
7. The same function as in the above embodiment can be obtained even if a device is used which is configured with a bearing 16 attached to the closed box 1, generates a driving force with a servo motor 14, and adjusts the amplitude with an encoder 15 to generate a vibrating force.

〔Effect of the invention〕

As explained above, according to the present invention, the drive device is installed between the lower part of the closure box and the installation part on the floor, and the drive device is driven in accordance with the vibration of the closure box, thereby controlling the closed distribution board. Since vibration is suppressed, it is possible to provide a vibration-damping closed switchboard in which electrical equipment housed inside the closed box is not damaged by vibration.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a detailed sectional view of part A in Fig. 1, Fig. 3 is a system block diagram applied to the present invention, and Fig. 4 is an earthquake FIG. 5 is a sectional view of another embodiment of the present invention, and FIG. 6 is a perspective view of a conventional closed power distribution board. 1. Closed box 2 Box frame 3 Electrical equipment 4. Installation parts 5a, 5b... Vibration sensor 6. Drive device 7.. Control device 8. Piston 9. Cylinder
10 Pressure supply device 13 Media agent Patent attorney Yoshiaki Inomata (and 1 other person) 5b Figure Figure Figure Figure Figure Figure

Claims (1)

[Claims] In a closed power distribution board in which electrical equipment is housed in a closed box, there is a sensor that detects horizontal vibration and vertical vibration of the closed box, and the output from this sensor is calculated to replace it with vertical vibration, and the calculation result is calculated. A control device that generates a frequency having the same amplitude and an opposite phase with respect to the amplitude and frequency of the vibration, and a drive device that vibrates the closed box in the vertical direction in accordance with the output of the control device. Vibration-damping closed switchboard.