JP2021131347A - Electromagnetic vibrometer - Google Patents

Abstract

To form compatibility between electromagnetic vibrometers having the same configuration by providing a structure capable of easily matching output voltages and attenuation factors between the electromagnetic vibrometers having the same configuration.SOLUTION: An electromagnetic vibrometer capable of detecting vibration by moving a conductor in a magnetic field includes a first winding 2a and a second winding 2b electrically insulated from the first winding 2a in a pendulum 1 movably arranged in the magnetic field. A circuit 5 including the first winding 2a and formed by connecting the first winding 2a and a sensitivity control resistance 6 in parallel can obtain an output by the first winding 2a, and a circuit 7 including the second winding 2b and formed by connecting the second winding 2b and an attenuation factor control resistance 8 in parallel can attenuate the movement of the pendulum 1 by the second winding 2b.SELECTED DRAWING: Figure 1

Description

The present invention relates to an improvement of an electromagnetic vibration meter.

There is an electromagnetic vibration meter that detects vibration when a conductor moves in a magnetic field. FIG. 2 is a cross-sectional configuration view of a main part of a typical electromagnetic vibration meter.

In FIG. 2, reference numeral 1 indicates a pendulum, reference numeral 1a indicates a weight constituting the pendulum 1, reference numeral 1b indicates a bobbin portion constituting the pendulum 1, and reference numeral 1c. Is a spring constituting the pendulum 1, reference numeral 2 is a winding as a conductor wound around the bobbin portion 1b, reference numeral 3 is a support of the pendulum 1, and reference numeral 3a is a support. Permanent magnets that are part of the body 3 side, reference numeral 3b is a magnetic material attached to one magnetic pole side of the permanent magnet 3a, and reference numeral 3c is the other magnetic pole of the permanent magnet 3b. It is a magnetic material provided with a bottom portion 3d attached to the side and a circumferential rising portion 3e surrounding the bottom portion 3d.

A magnetic field (the direction of the magnetic field lines is indicated by an arrow in FIG. 2) is formed in a concentric void 4 formed between the magnetic body 3b and the rising portion 3e of the magnetic body 3c, and the magnetic field is contained in the magnetic field. Winding 2 is located. In FIG. 2, reference numeral 5 indicates a circuit including the winding 2, and a resistor 6 is connected in parallel with the winding 2 to the circuit 5, so that an output can be obtained from the circuit 5. It has become.

Below,
m is the mass of the pendulum 1,
λ is a constant related to damping (braking force),
k is the spring constant of the spring 1c,
h is the damping constant,
ωn is the natural circular frequency,
B is the magnetic flux density,
l is the length of winding 2,
R1 is the resistance of winding 2,
Resistor 6 with R2 connected in parallel to winding 2
ei winding 2 electromotive force
eo output voltage,
It is explained as.

In FIG. 2, the support 3 side is the fixed side and the winding 1 side is the movable side, and the right half of FIG. 2 will be described (the directions of the magnetic field lines indicated by the arrows in FIG. 2 are from left to right on the paper). The voltage ei generated when the weight 1a constituting the pendulum 1 moves upward at a velocity v is expressed by Eq. (1) according to Fleming's right-hand rule.

From equation (1), the output voltage is proportional to the speed. The direction in which the voltage is generated is from the front to the back of the page.

In the electromagnetic vibration meter, electromagnetic braking is applied by inserting an electric resistance 6 in parallel with the circuit 5, and damping can be applied to the pendulum 1. By connecting the resistors 6 in parallel, a current i flows through the winding 2. When a current flows through the winding 2, a force is generated in the winding 2 in the direction opposite to the velocity v according to Fleming's left-hand rule.

The flowing current i is represented by Eq. (2).

The generated force is expressed by Eq. (3).

Equation (4) can be obtained from equations (1), (2) and (3).

The force λ generated from the equation (4) is proportional to the velocity v and acts in the direction opposite to the velocity direction of the pendulum 1, so that the pendulum 1 is braked (damped). The attenuation constant (h) due to the winding 2 is given by Eq. (5) from h = λ / (2mωn).

The attenuation constant can be adjusted by increasing or decreasing the resistance 6. The output voltage when the resistor 6 is connected is divided by the resistor of the winding 2 and the resistor 6 and is expressed by the equation (6).

From the above equations (5) and (6), both the attenuation constant and the output voltage can be finally adjusted by the resistor 6 connected in parallel with the winding 2, but the resistance (R1) of the winding 2 and the mass (m) of the pendulum 1 ), The natural circular frequency (ωn), and the magnetic flux density (B) vary in the electromagnetic vibration meters having the same configuration, and it is not easy to match the attenuation constants and output voltages between the electromagnetic vibration meters having the same configuration.

In the case of vibration measurement, an electromagnetic vibration meter corresponding to the three components (three directions of X, Y, and Z) is required. In many cases, a plurality of electromagnetic vibration meters are used at the same time in the measurement. However, it is difficult for the conventional electromagnetic vibrometers shown in FIG. 2 to have compatibility, and for this reason, it is necessary for the recording device to set the sensitivity for each electromagnetic vibrometer.

Therefore, it is an object of the present invention to provide a structure that makes it possible to easily match the output voltage and the attenuation constant between the electromagnetic vibration meters having the same configuration, and to have compatibility between the electromagnetic vibration meters having the same configuration. do.

In order to achieve the above object, in the present invention, an electromagnetic vibration meter is an electromagnetic vibration meter that detects vibration by a conductor moving in a magnetic field.
The pendulum, which is movably arranged in a magnetic field, has a first winding and a second winding that is electrically isolated from the first winding.
In the circuit including the first winding, the first winding and the resistor for sensitivity adjustment are connected in parallel so that the output is obtained by the first winding and the output is obtained.
A circuit including the second winding, in which the second winding and a resistor for adjusting an attenuation constant are connected in parallel, and the second winding makes it possible to attenuate the motion of the pendulum. And said.

According to the present invention, the output voltage and the attenuation constants of the electromagnetic vibration meters having the same configuration can be easily matched, and compatibility can be achieved between the electromagnetic vibration meters having the same configuration.

FIG. 1 is a cross-sectional configuration diagram of a main part of an electromagnetic vibration meter according to an embodiment of the present invention. FIG. 2 is a cross-sectional configuration view of a main part of a conventional electromagnetic vibration meter.

Hereinafter, a typical embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a main part of an electromagnetic vibration meter according to an embodiment of the present invention in a cross section in a direction along a moving direction of a pendulum 1 which will be described later.

The electromagnetic vibration meter according to this embodiment detects vibration by moving a conductor in a magnetic field. Such movements include relative movements due to the movement of the support 3 side, which will be described later.

In such an electromagnetic vibration meter, a pendulum 1 movably arranged in the magnetic field is provided with a first winding 2a, which will be described later, and a second winding 2b that is electrically insulated from the first winding 2a. I have.

Further, in the electromagnetic vibration meter, the circuit 5 described later including the first winding 2a is connected in parallel with the first winding 2a and the resistor 6 for adjusting the sensitivity. The output is obtained by the winding 2a, and the output is obtained.
Assuming that the circuit 7 described later including the second winding 2b is connected in parallel with the second winding 2b and the resistor 8 for adjusting the attenuation constant, the second winding 2b causes the pendulum 1 to be connected. The movement can be attenuated.

In FIG. 1, reference numeral 1 indicates a pendulum, reference numeral 1a indicates a weight constituting the pendulum 1, reference numeral 1b indicates a bobbin portion constituting the pendulum 1, and reference numeral 1c. Is a spring constituting the pendulum 1, reference numeral 2a is the first winding as a conductor wound around the bobbin portion 1b, and reference numeral 2b is a first winding as a conductor wound around the bobbin portion 1b. Two windings, reference numeral 3 is a support of the pendulum 1, reference numeral 3a is a permanent magnet that is a part of the support 3 side, and reference numeral 3b is one of the permanent magnets 3a. A magnetic material attached to the magnetic pole side, indicated by reference numeral 3c, is a magnet having a bottom portion 3d attached to the other magnetic pole side of the permanent magnet 3b and a circumferential rising portion 3e surrounding the bottom portion 3d. The body.

A magnetic field (the direction of the magnetic field lines is indicated by an arrow in FIG. 1) is formed in a concentric void 4 formed between the magnetic body 3b and the rising portion 3e of the magnetic body 3c, and the magnetic field is contained in the magnetic field. The first winding 2a and the second winding 2b are located.

In FIG. 1, reference numeral 5 indicates a circuit including the first winding 2a, in which a resistor 6 is connected in parallel with the first winding 2a, and an output is output from the circuit 5. You can get it.

Further, in FIG. 1, reference numeral 7 indicates a circuit including the second winding 2b, and a resistor 8 is connected in parallel with the second winding 2b in this circuit 7.

Below,
m is the mass of the pendulum 1,
λ is a constant (braking force) related to the attenuator 4,
k is the spring constant of the spring 1c,
h is the damping constant,
ωn is the natural circular frequency,
B is the magnetic flux density,
l is the length of the first winding 2a,
R1 is the resistance of the first winding 2a,
Resistor 6, which connects R2 in parallel with the first winding 2a,
eo output voltage,
LG is the length of the second winding 2b,
R3 is the resistance of the second winding 2b,
Resistor 8 in which R4 is connected in parallel to the second winding 2b,
λg is the damping force due to the second winding 2b,
hg is the damping constant due to the second winding 2b,
It is explained as.

The output voltage from the signal coil is expressed by Eq. (7).

The damping force (λg) due to the second winding 2b is expressed by Eq. (8).

The attenuation constant (hg) due to the second winding 2b is expressed by Eq. (9).

The damping constant of the entire pendulum 1 is the damping constant of the first winding 2a, the damping constant of the bobbin portion 1b when the bobbin portion 1b of the pendulum 1 is made of a magnetic material, and the damping constant of the second winding 2b. It becomes a sum.

From the above, the output voltage of the electromagnetic oscillator is independently connected to the first winding 2a by the resistor 6 connected in parallel, and the attenuation constant for the pendulum 1 is independently connected to the second winding 2b by the resistor 8 connected in parallel. You can see that it can be set.

As a result, according to the electromagnetic vibration meter according to this embodiment, the output voltage and the attenuation constant between the electromagnetic vibration meters having the same configuration can be easily matched, and the electromagnetic vibration meters having the same configuration are compatible with each other. It is possible to have sex.

In the embodiment described above, the first winding 2a and the second winding 2b are wound together on one bobbin portion 1b of the pendulum 1, but the winding position of the first winding 2a in the pendulum 1 The specific shape and structure of the electromagnetic vibration meter, such as winding the second winding 2b at a position different from the above and forming a magnetic field corresponding to each winding 2a and 2b on the support 3 side. May be appropriately changed as long as the object of the present invention can be achieved. That is, the present invention is not limited to the embodiments described above, but includes all embodiments that can achieve the object of the present invention.

1 pendulum 1a weight 1b bobbin part 1c spring 2a first winding 2b second winding 3 support 3a permanent magnet 3b magnetic material 3c magnetic material 3d bottom 3e rising part 4 void 5 circuit 6 resistance 7 circuit 8 resistance

Claims (1)

An electromagnetic vibration meter that detects vibration when a conductor moves in a magnetic field.
The pendulum, which is movably arranged in a magnetic field, has a first winding and a second winding that is electrically isolated from the first winding.
In the circuit including the first winding, the first winding and the resistor for sensitivity adjustment are connected in parallel so that the output is obtained by the first winding and the output is obtained.
Assuming that the circuit including the second winding has the second winding and the resistor for adjusting the damping constant connected in parallel, the second winding makes it possible to attenuate the motion of the pendulum. Type vibration meter.

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