JPH0429545A - Rotary field type synchronous machine - Google Patents

Abstract

PURPOSE:To prevent overheating of a specific brush and thermal deformation of a current collecting ring by constituting the current collecting ring of eccentric inner and outer current collecting rings having different conductivity thereby suppressing imbalance of current shunted from respective brushes to the current collecting ring. CONSTITUTION:A current collecting ring 13 comprises eccentric inner and outer current rings 13a, 13b having different conductivity. An exciting current flows from a conductor 12 sequentially through a conductor 9 and each brush 7 to the outer current collecting ring 13b thence to the inner current collecting ring 13a. Current shunted from the leftmost brush decreases whereas current shunted from the rightmost brush 7 increases. Consequently, difference between currents shunted from the rightmost and leftmost brushes can be suppressed resulting in prevention of heating of the left most brush 7 or distortion of the current collecting ring due to partial heating.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a rotating field type synchronous machine.

(Prior Art) In FIG. 8, which shows a partial vertical cross-sectional view of a conventional rotating field type synchronous machine (hereinafter referred to as a synchronous machine), on the rotating part side, a cross-sectional ring-shaped machine is equipped with a field winding (not shown). An annular current collecting ring 4 is attached to the outer periphery of the rotating shaft 2 via a body insulator 3, and the inner periphery of the current collecting ring 4 is T-shaped in the figure and L-shaped in the top view of the same figure (not shown). One end of a strip-shaped conductor 5 is joined, and the other end of this conductor 5 is connected to a field winding (not shown).

On the other hand, insulating studs 10 (details omitted) are fixed to both ends and the center of the semicircular strip conductor 9 provided on the fixed side, and a connecting conductor 12 is connected to the left end of the conductor 9. is connected to an external DC power supply (not shown).

By the way, with advances in power electronics technology, synchronous machines are now being used in metal rolling equipment along with induction machines.

At this time, the overall power factor of the synchronous machine combined with the cycloconverter is superior to that of the induction machine, so
Power supply capacity is small. In contrast, induction machines quickly establish magnetic flux to obtain the required torque and have excellent controllability.

On the other hand, a synchronous machine has a large number of field winding turns and a long circuit time constant, so it is slower to establish magnetic flux than an induction machine.

As a countermeasure for this, there are times when direct current is applied to the stationary field slightly faster than the energization of the stator armature to establish magnetic flux and prepare for the operation command.

(Problem to be solved by the invention) At this time, however, in the conventional synchronous machine, a uniform current does not flow through all the brushes, and the temperature of a particular brush exceeds the allowable value, resulting in the brush coming into contact with the other brushes. There is also the possibility that the current density increases locally in the current collecting ring, causing local overheating and causing the current collecting ring to become distorted.

That is, in FIG. 8, the connecting conductor 12 to the conductor 9.
The current shown by the arrow leading to the field winding (not shown) via the brush 7, the current collector ring 4 and the conductor 5 is connected to the brush 7 on the left end in the figure.
The current that is shunted from the current collector ring 4 is the maximum, and decreases toward the right side from there.

Furthermore, if the angle of the rotating shaft when it is stopped deviates and it comes to the center of the conductor 5, the unbalance of the currents that flow to each brush 7 is somewhat alleviated, but it is still insufficient.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotating field type synchronous machine that can prevent overheating of the brushes and deformation of the current collection ring.

[Configuration of the Invention (Means and Effects for Solving the Problems) The present invention provides a rotating field type synchronous machine in which a plurality of brushes are arranged between a conductor and a current collecting ring, in which the current collecting ring is By constructing an eccentric inner and outer collector ring with different conductivities, it alleviates the unbalance of the excitation current flowing through each brush, and prevents deformation of the collector ring due to unbalanced current between the brushes. It is a rotating field type synchronous machine.

(Example) Hereinafter, an example of a synchronous machine of the present invention will be described with reference to the drawings. However, parts that overlap with Fig. 8 are omitted.

In FIG. 1, the current collecting ring 13 includes an inner current collecting ring 13a and an outer current collecting ring 13 having different conductivities and having eccentric inner and outer circumferences.
It is manufactured by press fitting b.

Of these, the inner current collector ring 13a is made of stainless steel and machined using a lathe, and the outer current collector ring 13b is made of hard copper and manufactured using the same lathe with the same amount of eccentricity as the inner current collector ring 13a. In order that the inner circumference of the ring 13a and the outer circumference of the outer current collecting ring 13b are concentric, the difference between the inner and outer circumferences of the outer current collecting ring 13b is the largest at the part where the difference between the inner and outer circumferences due to the eccentricity of the inner current collecting ring 13a is the smallest. It is press-fitted in line with the part.

Next, the operation of the synchronous machine configured in this way will be explained.

In the figure, conductors 12 to 9. Brush 7° short circuit ring 13. The excitation current that passes through the conductor 5 and passes through the field winding (not shown) flows from the conductor 9 through each brush 7 into the outer current collecting ring 13b in order, as shown by the arrows in the figure, and then flows into the inner current collecting ring 13a. Inflow. Among them, the current branched from the leftmost brush 7 flows into the inner current collecting ring 13a through the thickest part of the outer current collecting ring 13b, which has a high specific resistance.
The current is reduced compared to when the current collecting ring 4 is used as shown in FIG.

On the other hand, since the current flowing from the brush 7 at the right end flows through the vicinity of the thinnest part of the outer current collector 13b, the current increases compared to the left end if the voltage drop due to the conductor 9 is ignored.

As a result, the difference between the currents branching from the left and right ends can be reduced, resulting in a synchronous machine that can prevent distortion due to heating of the brush 7 at the left end or partial heating of the current collecting ring.

In the above embodiment, the eccentricity and conductivity ratio of the inner current collector ring 13a and the outer current collector ring 13b are determined by the voltage drop between the left and right ends of the conductor 9 (i.e. conductivity, current carrying cross-sectional area, length, etc.). ), for example, the eccentricity and conductivity ratio may be increased when the voltage drop is large, and conversely reduced when the voltage drop is small.

FIG. 2 is a partial vertical sectional view showing another embodiment of the synchronous machine of the present invention.

In the figure, the inner periphery of the outer current collecting ring 13b at the press-fit portion between the inner current collecting ring 13a and the outer current collecting ring 13b on the outside of the conductor 5 is shown in FIG. The fourth indicating
As shown in the figure, a groove is formed, into which an insulating plate 16 made of glass-reinforced polyester resin is inserted and fixed with epoxy resin.

In this case, the current shunted from the leftmost brush 7 to the outer current collecting ring 13b bypasses both sides of the insulating plate 1B, so the current shunted from the leftmost brush 7 can be reduced, and the current shunted from the leftmost brush 7 to the rightmost This is a synchronous machine that can further reduce the deviation of the shunt current from the brush 7.

FIG. 5 shows another embodiment of the synchronous machine of the present invention.

In the figure, the connecting conductor 14 connected to the conductor 9 branches and is also connected to the right end of the conductor 9.

In this case, the potential difference between the left and right ends of the conductor 9 is reduced compared to the cases shown in FIGS. It becomes a synchronous machine that can further reduce the number of times.

FIG. 6 shows yet another embodiment of the synchronous machine of the present invention. In the figure, an inner current collecting ring 14a having a substantially triangular outer periphery is press-fitted into the inner periphery of the outer current collecting ring 14b, and conductors 5 are inserted through the rotating shaft 2 at a pitch of 120'.

In addition, an insulating plate 16 is fixed to the outer periphery of the inner current collecting ring 14a and the inner periphery of the outer current collecting ring 14b at a portion facing one end of the conductor 5 of the press-fitted portion, as shown in FIG. 7 showing a detailed view thereof. has been done.

In this case, there is an advantage that the influence of the stopping angle of the rotating shaft 2 can be further reduced.

[Effects of the Invention] As described above, according to the present invention, in a rotating field type synchronous machine in which a plurality of brushes are arranged between a conductor and a current collecting ring, the current collecting rings are eccentrically arranged with different conductivities. By constructing an inner current collecting ring and an outer current collecting ring, the unbalance of the current shunted from each brush to the current collecting ring is reduced, which prevents overheating of a specific brush and thermal deformation of the current collecting ring. A rotating field type synchronous machine can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partial longitudinal sectional view showing one embodiment of the rotating field type synchronous machine of the present invention, and FIG. 2 is a partial longitudinal sectional view showing another embodiment of the rotating field type synchronous machine of the present invention. 3 is a diagram showing the main part of FIG. 2, FIG. 4 is a sectional view taken along line AA in FIG. 3, and FIG. 6 is a partial longitudinal sectional view showing still another embodiment of the rotating field type synchronous machine of the present invention, FIG. 7 is a view showing the main part of FIG. 6, and FIG. FIG. 2 is a partial longitudinal sectional view showing an example of a rotating field type synchronous machine. 2... Rotating shaft 7... Brush 9... Conductor 12... Connection conductor 13... Current collecting ring 13a... Inner current collecting ring 13b... Outer current collecting ring agent Patent attorney Boar Yoshiaki Mata (1 idiot) No. A Section No. Same Figure No.

Claims (1)

[Claims] In a rotating field type synchronous machine in which a plurality of brushes are arranged between a conductor and a current collecting ring, the current collecting ring is composed of an eccentric inner current collecting ring and an outer current collecting ring having different conductivities from each other. A rotating field type synchronous machine characterized by: