JPS6233485Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an abnormality detection device that detects electrical discharge in electrical equipment that generates electrical discharge during abnormal conditions and can detect abnormalities in the electrical equipment in advance.

Electrical equipment For example, when a three-phase induction motor is in operation, the current collector consisting of the brush and slip ring of the three-phase induction motor has a nearly constant state due to friction as the three-phase induction motor operates. It wears out gradually. Therefore, if the amount of wear of the brush after operation is periodically inspected, it is possible to predict the life of the brush based on conventional measured data. Based on the results of this periodic inspection, it is possible to determine the maintenance period for the current collector portion of the three-phase induction motor.

However, if an abnormal situation occurs at the contact surface between the brush of the current collector and the slip ring due to, for example, foreign matter entering the three-phase induction motor during operation,
A spark discharge occurs between the brush and the slip ring, damaging a portion of the brush contact surface. When such a phenomenon occurs, smooth contact between the brush and the slip ring becomes impossible, spark discharge becomes constant, and wear of the brush due to discharge is accelerated. In this state, the magnitude of the spark discharge increases at an accelerating rate, and eventually the current collector of the three-phase induction motor burns out. Once such burnout occurs in the current collector, this burnout is not limited to just the current collector, but after 7 to 8 hours, the insulation around the current collector may also be damaged by heat. . When such an accident occurs, a great deal of time and effort is required to restore it, and if the motor that caused the accident is a key piece of equipment in a given process, it may be difficult to stop the work due to the accident. The negative effects will be immeasurable.

On the other hand, rotating electrical equipment is characterized by the short time it takes from the occurrence of an abnormality during periodic inspection until it causes a burnout accident. Therefore, if an abnormality occurs immediately after a periodic inspection, it is inevitable that it will spread to a burnout accident. If we can detect this abnormal situation early, we can stop the rotating electrical equipment in operation and replace, repair, or maintain the equipment before it spreads to the burnout accident, thereby preventing the occurrence of this serious downtime. I can do it. Conventionally, there has been no effective means for early detection of abnormalities in electrical equipment, and this has been dealt with by increasing the number of periodic inspections as much as possible.

This invention solves the drawbacks of these conventional methods and provides an abnormality detection device that has a simple structure and enables early detection of abnormalities in various electrical devices quickly and accurately.

According to this invention, an antenna is provided near a spark discharge source that generates spark discharge in an electrical device, and an amplifier circuit is connected to this antenna to detect spark discharge and shape and amplify the electrical signal based on the detected spark discharge. The electrical signal based on the spark discharge obtained in this way is applied to a comparison circuit connected after the amplifier circuit, and this comparison circuit detects that the obtained electrical signal exceeds a preset reference value. The first alarm circuit is driven by the output of this comparison circuit every time the first alarm is generated, and the first alarm is generated. Further, a second alarm circuit is provided after the first alarm circuit, and when the first alarm circuit continuously generates an alarm, the second alarm circuit
A second alarm signal is generated by the alarm circuit to detect an abnormality in the electrical equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The abnormality detection device of this invention will be described in detail below based on its embodiments using the drawings.

FIG. 1 shows the structure of the surrounding part of the current collector in an embodiment of the abnormality detection device of this invention.
is arranged in a protruding manner, and slip rings 13-1 to 13-3 are attached to this rotating shaft 12. These slip rings 13-1 to 13-3
brushes 14-1, 14-2, 15 so as to be in contact with
-1, 15-2 and 16-1, 16-2 are arranged. Although not shown, these brushes 14-1~
External lead wires are connected to 16-2, respectively,
These external lead wires connect the motor body 11
Three-phase AC power is supplied from outside.

A current collector consisting of these slip rings 13-1 to 13-3 and brushes 14-1 to 16-2 is housed in a current collector cover 17 that surrounds the rotating shaft 12 in the direction of the rotating shaft 12 of the motor. Ru.
A cover plate 18 is provided on the open side of the current collector cover 17.
is removably attached, and the cover plate 18 is removed when inspecting, repairing, or replacing the current collector section.

An antenna 19 is attached to the wall surface of the current collector cover 17. A rod-shaped antenna is used as the antenna 19, for example, a copper rod with a diameter of 2 mm and a length of 15 cm. This antenna 19 is connected to the coaxial cable connector 2 as shown in FIG.
Using this coaxial cable connector 20, the antenna 19 is attached perpendicularly to the wall surface of the current collector cover 17 by screwing and fixing, for example. The antenna 19 is attached to the current collector cover 17 with the slip ring 13-
1 to 13-3 and brushes 14-1 to 16-2, and not too close to current collector cover 17. Further, when the voltage applied to the slip rings 13-1 to 13-3 is high, it is necessary to arrange the slip rings 13-1 to 13-3 sufficiently separated from these.

In electrical equipment, the operation of the current collector becomes abnormal and an abnormal rectification state occurs, causing the brushes 14-1 to 16-
When a spark discharge occurs between the slip rings 2 and the slip rings 13-1 to 13-3, the spark discharge generates a noise radio wave. The noise radio waves generated by this spark discharge have a waveform that includes signals with a wide range of frequency components over approximately 2KHz. An output terminal of the antenna 19 is connected to an amplifier 22 via a coaxial cable 21, and a rectification and shaping circuit 23 is connected to the amplifier 22. Although not shown, the amplifier 22 has a built-in switching circuit for selecting a desired pass frequency band. The electrical signal S ₁ rectified and shaped by the rectification and shaping circuit 23 is given as an input to the inverting input terminal of the comparison circuit 24 . A galvanometer 10 is provided to display the output signal of the rectifying and shaping circuit 23, and the configuration is such that the output signal level can be displayed. A reference voltage setter 25 is connected to the non-inverting input terminal of this comparison circuit 24.
A reference voltage signal S ₀ set by is given as an input.

The reference voltage of the reference voltage signal S ₀ can be set to a predetermined value by adjusting the variable resistor 26 of the reference voltage setter 25. The set value set by this variable resistor 26 is displayed on a voltmeter 27 connected in parallel to the variable resistor 26, so set a predetermined reference voltage signal _S0 while checking the displayed value. It can be applied to the non-inverting input terminal of the comparison circuit 24.

The output terminal of the comparison circuit 24 is connected to the base of a transistor 29 via a resistor 28. A predetermined bias voltage E _B is applied to the collector of the transistor 29 via a resistor 30, and the emitter of the transistor 29 is grounded. When the electric signal S ₁ applied to the inverting input terminal of the comparator circuit 24 exceeds the reference voltage signal S ₀ applied to the non-inverting input terminal, a pulse-shaped negative detection signal S ₂ is output to the output terminal of the comparator circuit 24. appears. This detection signal _S2 causes the normally conductive transistor 29 to become non-conductive.

A connection point between the collector of transistor 29 and resistor 30 is connected to the base of transistor 32 via resistor 31, and the emitter of transistor 32 is grounded. Further, the cathode side of a light emitting diode 33 is connected to the collector of the transistor 32, and a predetermined bias voltage E _B is applied to the anode side of the light emitting diode 33 via a resistor 34.

Therefore, when transistor 29 becomes non-conductive, a predetermined voltage is applied to the base of transistor 32, and transistor 32 becomes conductive. When the transistor 32 becomes conductive, a current flows between the anode and the cathode of the light emitting diode 33, and the light emitting diode 33 is activated.
Light. In this way, every time the peak value of the electrical signal _S1 based on the spark discharge applied to the inverting input terminal of the comparator circuit 24 exceeds the reference voltage signal _S0 applied to the non-inverting input terminal, it is independent of the duration. The light emitting diode 33 lights up to issue the first alarm. For example, by recording the blinking state of the light emitting diode 33, it can be used as historical data of the operating state of the electrical equipment.

Diode 35 is connected to the connection point between resistor 30 and resistor 31.
The cathode side of the diode 35 is connected, and the anode side of the diode 35 is connected to the emitter of a single junction transistor 36. Further, the emitter of the transistor 36 is grounded via a capacitor 37. A variable resistor 38 is connected between the emitter of the transistor 36 and the cathode side of the diode 35. A predetermined bias voltage E _B is applied to the first base of the transistor 36 via a resistor 39.
is applied, and the second base of transistor 36 is grounded via resistor 40. Also transistor 3
The cathode side of a diode 42 is connected to the second base of the diode 42 via a resistor 41.
A relay circuit 44 is connected to the anode side of the
One end of is connected. One end of a reset switch 9 is connected to the other end of the relay circuit 44, and a predetermined bias voltage E _B is connected to the other end of the reset switch 9.
is applied.

The cathode side of the diode 42 is grounded, and the connection point between the cathode side of the diode 42 and the resistor 41 is connected to the resistor 45.
is grounded through. Predetermined bias voltage E _B
One end of the relay contacts 46 and 48 are respectively connected to one end of the reset switch 9 to which the voltage is applied. A buzzer 47 is connected between the other end of the contact 46 of this relay and ground. The other end of the relay contact 48 is connected to the anode side of a light emitting diode 50 via a resistor 49, and the cathode side of the light emitting diode 50 is grounded.

When the electric signal S ₁ generated based on the spark discharge exceeds a predetermined reference value and a detection signal S ₂ is generated, the voltage on the cathode side of the diode 35 increases and the diode 35 enters a cutoff state. Therefore, discharge of the capacitor 37 is prevented, and charges are accumulated in the capacitor 37 via the resistor 38. Therefore, when the duration of the detection signal _S2 exceeds a predetermined time and the charge charged in the capacitor 37 becomes sufficiently large, the transistor 36 is turned off. When the transistor 36 is cut off, the voltage on the cathode side of the diode 42 decreases, and the diode 42 becomes conductive. When diode 42 becomes conductive, an operating current flows through relay circuit 44 . Since the cathode side of the diode 42 is directly grounded, once a conductive state occurs, that state is maintained.

Since the relay contact 46 is closed by this operating current, the buzzer 47 is activated to emit a predetermined alarm sound. The operating current also closes the relay contacts 48 and lights up the light emitting diode 50 to provide a visual alarm. Therefore, when the maintenance inspector confirms the alarm sound from the buzzer 47 or the lighting of the light emitting diode 50, he or she should turn the reset switch.
You can turn it off to stop the alarm circuit, and then stop the electrical equipment to repair or replace it. If necessary, press the reset switch 9.
If you turn it off, the alarm display will be canceled.

In this way, an electrical signal S ₁ is generated based on the spark discharge, and if this electrical signal S ₁ is greater than the reference voltage signal S ₀ even momentarily, the light emitting diode 33 lights up, visually indicating the first alarm. is served. However, if it is an instantaneous spark discharge that does not lead to a failure of the current collector of the electrical equipment, the second alarm circuit will not operate and the buzzer 47 and light emitting diode 5 will not operate.
0 does not work. However, even instantaneous spark discharges can lead to current collector failures if they occur frequently with short pauses. In such cases, the electrical signal S ₁ based on the instantaneous spark discharge
When the voltage exceeds the reference voltage signal S ₀ , the capacitor 37 is charged for that period of time. Therefore, capacitor 3
Even if there is a pause interval to discharge the charge of 7, the charging time based on instantaneous spark discharges accumulates,
When the cumulative charge exceeds a predetermined value, the buzzer 47 and the light emitting diode 50 are activated to warn of an abnormality in the electrical equipment.

In this way, according to the abnormality detection device of this invention, even if an instantaneous spark discharge occurs, it is stored and accumulated, and when it exceeds a predetermined value, an alarm circuit is activated, thereby preventing damage to the current collector due to cumulative discharge. It is also possible to sufficiently prevent this.

The abnormality detection device of this invention is directly applied to the current collector of a commutator machine, and the noise level V _N can be determined depending on the number n of sparks generated between the brush and the commutator.
When measuring whether an output signal of 1 is obtained, it is found that there is a substantially linear relationship between the two as shown in FIG. Therefore, according to the abnormality detection device of this invention,
It is possible not only to qualitatively detect an electrical signal based on spark discharge, but also to perform quantitatively accurate operation such as generating an alarm signal when spark discharge exceeds a predetermined value. Normally, if the alarm set level Se is set to a state where the number of sparks is about 4 in FIG. 4, an alarm that meets the actual purpose of inspection can be obtained. In this way, an alarm will be issued at a certain predetermined point in time if the spark discharge becomes permanent and has a tendency to gradually increase in magnitude. The effect is especially great when applied to DC commutator machines where spark discharge is constant even under normal conditions.

In the embodiment, the case where the abnormality detection device of this invention is used in rotating equipment has been described, but it can also be used to detect dielectric breakdown in stationary equipment, such as a high-voltage electromagnetic panel. In high-voltage electromagnetic panels, corona discharge occurs before dielectric breakdown, so it is possible to detect the occurrence of an abnormality by detecting an electrical signal based on this corona discharge.

As explained in detail above, the abnormality detection device of this invention can detect burnout accidents in rotating electrical equipment and stationary electrical equipment, and fire accidents that occur along with such accidents by detecting electrical discharges that occur during abnormal situations. It can be detected accurately and alerted. The configuration of the device is simple, and since it operates based on the cumulative value of instantaneous discharge, it is possible to detect in advance a discharge condition that could lead to a serious accident, and to operate only at the desired set quantitative value to prevent abnormal accidents from occurring. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of the surrounding part of the current collector of the embodiment of the abnormality detection device of this invention, in which A is a side view with a part cut away, B is a front view with the cover plate removed, and Fig. 2 3 is a block diagram showing the configuration of an embodiment of the anomaly detection device of this invention. FIG. 4 is a diagram showing the number of sparks and the noise level. It is a figure showing a relationship. 11: Electric motor body, 13-1 to 13-3: Slip spring, 14-1, 14-2, 15-1, 1
5-2, 16-1, 16-2: Brush, 17: Current collector cover, 19: Antenna, 22: Amplifier, 2
3: Rectification shaping circuit, 24: Comparison circuit, 25: Reference voltage setter, 33, 50: Light emitting transistor, 3
5, 42: Diode, 37: Capacitor, 4
4: Relay circuit, 47: Buzzer, 46, 48: Relay contact.

Claims (1)

[Claims for Utility Model Registration] An antenna provided near a spark discharge source that generates spark discharge in an electrical device; an amplifier circuit connected to the antenna and capable of obtaining an electrical signal based on the spark discharge as an output; a comparison circuit connected to the amplification circuit and configured to detect that an electric signal generated based on the spark discharge exceeds a preset reference value; and a comparison circuit driven by the output of the comparison circuit and based on the spark discharge It has a first alarm circuit that generates a first alarm each time the electric signal exceeds the set reference value, and a second alarm circuit that generates a second alarm when the first alarm circuit continuously generates an alarm. An anomaly detection device characterized by: