JPH0315704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brush spark monitoring device for monitoring sparks generated around brushes that contact a commutator and a collector ring of a rotating electric machine.

Sparks generated around the brushes that come into contact with the commutator and collector ring of a rotating electric machine, exceeding a certain limit, are an abnormal phenomenon, and there is a risk of damage to the rotating electric machine, fire, and other accidents.

Conventionally, visual inspections by maintenance personnel have been carried out on a daily basis to detect abnormalities in sparks generated around the brushes of rotating electric machines, and it requires a considerable amount of manpower to carry out these tasks on a regular basis every day. They are forced to enter around dangerous brushes where voltage is being applied. Still, these types of accidents still occur and pose a threat to plant safety.

Conventionally, as a detection device of this type, there is a method of optically detecting sparks from a brush. The effect can be strange in small-capacity rotating electric machines, but especially in large-capacity synchronous machines, brushes are installed in many locations, and the diameter and length of the collector ring are large, making it difficult to place the optical detection device close to the sliding parts. , and there is a problem with the mounting structure in order to cover the entire range of the brushes. Furthermore, there is a problem in that the parts of the brush where the arc cannot be seen are essentially undetectable, so it has been desired to develop some kind of different brush spark monitoring system.

This invention was made in view of the above circumstances, and it is possible to continuously monitor the presence or absence of spark abnormalities around the brushes of rotating electric machines and operate a protection circuit if necessary, thereby preventing damage to the brushes. It is an object of the present invention to provide a brush spark monitoring device that can prevent damage to a rotating electrical machine by detecting the cause at an early stage.

The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 shows the configuration of a main part of an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A--A in FIG. 1 and viewed in the direction of the arrow. Brush holder support 2 on the outer periphery of collector ring 1
A number of brush holders 3 are attached to the brush holder support 2. A brush 4 is supported by the brush holder 3 and is in contact with the collector ring 1. The brush holder support 2
An antenna support 5 made of an insulator is attached to the inner diameter side of the antenna. An antenna 6 is wound around the antenna support 5 a predetermined number of times as shown in FIG.

Moreover, as shown in FIG. 3, this antenna support 5
A dovetail portion 5b is formed in the brush holder support 2, and the dovetail portion 5b can be fitted into a dovetail receiving groove (not shown) formed in the brush holder support 2. An antenna support 5 is attached.

The terminal of the antenna 6 is connected to a known detection circuit 7 as shown in FIG. 4, where the electromagnetic wave signal induced in the antenna 6 is amplified and controlled. The output of the detection circuit 7 is input to a signal transmitter 8, which outputs a signal for protecting the rotating electric machine or activates a relay.

In the device configured as described above, if there is no spark between the brush 4 in contact with the collector ring 1, no electromagnetic waves are present in the vicinity of the antenna 6, so no signal is output to the detection circuit 7. At this time, even if the current waveform flowing through the brush 4 is a rectified current including a spike waveform that is very similar to the spark waveform caused by a thyristor, it will not be erroneously detected as long as no spark occurs.

If a spark occurs between the brush 4 and the collector ring 1, the spark generated by the voltage generates electromagnetic waves, so the detection circuit 7 detects the electromagnetic waves using the antenna 6 near the tip of the brush 4. You can know when a spark is generated.

Furthermore, in the embodiment of the present invention, the antenna 6 is attached as close as possible to the spark generating part, that is, in a part close to the collector ring 1 of the brush holder 3, so that it can be easily detected, so that many effects can be expected. Furthermore, unlike the optical detection method, the electromagnetic wave detection method of the embodiment of the present invention is capable of detecting even if there are some obstacles, and the detector is not contaminated with carbon etc. as in the case of optical detection. There is no decrease in detection ability. In this case, since the electromagnetic wave output changes depending on the strength of the spark, it is possible to judge whether it is a normal level or an abnormal level based on its magnitude. Level display and protection device operation can be selected as required.

Further, in this embodiment, since the antenna 6 is wound around the antenna support 5, the sensitivity to electromagnetic waves of a specific frequency of sparks determined by the collector ring, brush, power supply voltage, etc. can be increased. In this way, if the sensitivity of the antenna is increased using each antenna support as a unit, and the signal is guided to the detection circuit 7 for each antenna support as shown in FIG.
You can also see where sparks are generated from a distance.

Note that this invention is not limited to the embodiments described above, but can be modified and implemented as follows. To attach the antenna support 5 to the brush holder support 2, the dovetail 5b may not be inserted into the dovetail receiving groove, but may be fixed with a screw or the like.

Further, the antenna 6 may be attached to an antenna support 5, not the brush holder support 2, as shown in FIG. 5, but to a portion of the brush holder 3 near the collector ring 1, and the antenna 6 may be attached to this as described above. Further, in the above-mentioned embodiment, the case where the brush 4 is in sliding contact with the collector ring 1 has been described, but the same implementation can be performed even if the collector ring 1 is replaced with a commutator.

According to the above-described invention, an antenna support is attached to a brush holder support or a position near the brush sliding contact portion of the brush holder, etc., and an antenna for detecting electromagnetic waves induced by sparks generated by the brush is wrapped around the antenna support. Since it is connected to a known detection circuit that amplifies and controls the electromagnetic waves induced in this antenna, it is possible to detect sparks generated around the brushes of rotating electric machines at an early stage, thereby preventing damage to the rotating electric machines. Furthermore, by providing the detection circuit with a signal transmitter that outputs a signal for operating the protection device for the rotating electrical machine, it is possible to provide a brush spark monitoring device that can automatically protect the rotating electrical machine.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an axial cross-sectional view near the brush for explaining the spark detection section of the present invention, and Fig. 2 is a diagram cut along the line A-A in Fig. 1 and viewed in the direction of the arrow. , FIG. 3 is a perspective view of the antenna support shown in FIGS. 1 and 2, FIG. 4 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 5 shows an attached state of the antenna support in a modified example of the present invention. FIG. 1...Collector ring, 2...Brush holder support, 3...Brush holder, 4...Brush,
5... Antenna support, 6... Antenna, 7... Detection circuit, 8... Signal transmitter.

Claims (1)

[Claims] 1. A brush holder that holds a brush that is in sliding contact with a commutator or collector ring of a rotating electrical machine, or an antenna support that is attached to a brush holder support that supports this brush holder, and a wire that is wound around the antenna support and that includes the brush and the commutator or An antenna that detects electromagnetic waves induced by sparks generated between the collector ring, a detection circuit that detects the electromagnetic wave signal detected by this antenna, and an input of the output of this detection circuit to protect the rotating electric machine. A brush spark monitoring device comprising a signal transmitter that outputs a signal.