JP2001178095A - Rotary transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary transformer which can surely supply power to the rotating side, transmit a detection signal on the rotating side to the fixed side, and in particular, can be suitably applied to a field ground fault detecting apparatus of an AC generator. SOLUTION: A rotating side power source coil 21 and a fixed side power source coil 24 are wound around a rotating shaft 22, and a voltage to be applied to the coil 24 is made to be induced in the coil 21. A rotating side signal transfer coil 26 and a fixed side signal transmission coil 27 are made to face each other in a part of a rotor core 23 and a part of a stator core 25, and are wound around a shaft rectangular to the rotating shaft 22. A voltage, based on a signal supplied to the coil 26, is made to be induced in the coil 27, thereby making perform it signal transmission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary truss, and more particularly, to a rotary truss that is useful for detecting a ground fault in a generator field winding.

[0002]

2. Description of the Related Art Various devices have been proposed for detecting a ground fault in a field winding of a generator. FIG. 3 is a circuit diagram showing one example thereof together with the excitation device. As shown in the figure,
The exciter has an exciter 1, a rotary rectifier 2 and a field winding 3, rectifies an AC voltage generated by the exciter 1 with the rotary rectifier 2, and converts a DC voltage as an output signal into a field voltage. The voltage is applied to the winding 3. In such a configuration,
A field magnetic flux is generated by a current flowing through the field winding 3. Here, a DC power supply 5 and a resistor 6 are connected in series between the negative side of the field winding 3 and the ground 4, and these constitute a ground fault detector. This ground fault detector detects a field winding ground fault by detecting a potential change on the minus side of the field winding 3 or a weak current. Further, at this time, the exciter 1, the rotary rectifier 2, the field winding 3, the DC power supply 5, and the resistor 6, which are portions surrounded by a dotted line in the figure, constitute a rotating unit I that rotates integrally.

In such a ground fault detector, in order to determine a ground fault on the rotating unit I side, some kind of detection unit (such as a printed circuit board) is used.
, But it is necessary to supply power to it. If a ground fault is detected, the signal must be transmitted from the rotating unit I to the fixed side. Therefore, in the related art, a method using an output of an exciter as a power source, a method of installing a power supply coil in the exciter, a method using a rotary transformer, and the like have been proposed. Further, as a method of transmitting a ground fault signal, a method using a rotary transformer, a method in which a transmitter is mounted and a radio wave, a method using a pulse transformer, a method using an optical sensor, and the like have been proposed.

FIGS. 4A and 4B show a specific example in which a rotary transformer is used as a power supply and a signal transmitting means. FIG. 4A is a circuit diagram thereof, FIG. 4B is a plan view showing the rotary transformer extracted, and FIG. ) Is a longitudinal sectional view thereof. In the figure, 7 is a printed circuit board, 8 is a rotary transformer, and 9 is a generator board. The rotary transformer 8 includes two rotary unit coils 8c and 8d wound around a rotor core 8a that rotates integrally with the rotary unit I,
It has fixed part coils 8e and 8f wound around the fixed core 8b. Thus, the electric power induced by the electromagnetic coupling from the fixed part coil 8e to the rotating part coil 8c is supplied to the DC power supply 5 and the resistor 6 arranged on the printed circuit board 7 and the ground fault signal supplied from the printed circuit board 7 side Is transmitted from the rotating coil 8d to the failure determination unit and the alarm output unit of the external generator panel 9 via the fixed unit coil 8f.

FIG. 5 shows a specific example in which an AC exciter is used as a power source and a signal transmission coil is used as signal transmission means. FIG. 5 (a) is a circuit diagram thereof, and FIG. And (c) is a longitudinal sectional view thereof. In the figure, 10 is a printed circuit board, 11
, A power converter mounted on the printed circuit board 7, 12 an exciter, and 13 a signal transmission coil functioning as a pulse transformer. The necessary power in this case is a part of the rotating unit I, and is supplied from the exciter 12 that rotates integrally with the rotating unit I via the power converter 11. The signal transmission coil 13 includes a rotating part coil 13a that rotates integrally with the rotating part I and a fixed part coil 13b that is electromagnetically coupled to the rotating part coil 13a, and transmits a ground fault signal supplied from the printed circuit board 7 to the rotating part coil. 1
3a through the fixed part coil 13b to the external generator panel 9
To a failure determination unit and an alarm output unit.

[0006]

Among the prior arts described above, in the method using the output voltage of the exciter 12 as the power supply, the power supply voltage fluctuates depending on the load state of the generator. It is necessary to mount a power supply converter 11 for smoothing the power supply voltage on the printed circuit board 1.
There is a problem that the size of 0 is increased. On the other hand, in the method using the rotary transformer 8 as a signal transmission method, the signal transmission can be performed reliably, but the rotary transformer coil 8b and the fixed part coil 8d are provided only for the signal transmission. It is shaped and there is a disadvantage in production. Further, in the method using the transmission coil 13, in the case of a high-speed rotating machine, not only is it difficult to balance the rotation, but also because the output voltage is pulse-shaped, the pulse width decreases as the rotation speed increases, and the generator board 9 side In this case, it becomes difficult to design a failure detection circuit. Furthermore, in the method using radio waves, malfunctions due to noise and problems of EMC (radio wave interference) may occur, and in the method using optical sensors, signal detection accuracy may decrease due to contamination or the like, and continuous operation for a long time may occur. The problem is that it is not suitable to be applied to a generator that generates power.

SUMMARY OF THE INVENTION In view of the above prior art, the present invention can supply power to the rotating side and transmit the detection signal on the rotating side to the fixed side satisfactorily. It is an object of the present invention to provide a rotary transformer applicable to a computer.

[0008] The structure of the present invention that achieves the above object is a rotor core that rotates integrally with a rotating shaft, and a rotating side power supply coil wound around the rotating shaft and a rotor core that is rotated by a gap. A fixed-side power supply coil wound around the rotation axis in the opposed stator core; a rotation-side signal transmission coil wound around an axis perpendicular to the rotation axis in a part of the rotor core; A part of the sub-core includes a rotation-side signal transmission coil wound around an axis perpendicular to the rotation axis so as to face the fixed portion signal transmission coil.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.
(A) is a longitudinal sectional view, and (b) is a side view. As shown in both figures, the rotation-side power supply coil 21 is
It is wound around a rotation axis around a rotor core 23 that rotates integrally with the rotor core. The fixed-side power supply coil 24 is wound around a rotation axis in a stator core 25 opposed to the rotor core 23 via a gap. That is, the rotating power supply coil 21 and the fixed power supply coil 24 are wound concentrically. Thus, when power is supplied to the fixed-side power supply coil 24 to generate a magnetic flux, the magnetic flux interlinks with the rotation-side power supply coil 21 through the stator core 25 and the rotor core 23, and A predetermined voltage is generated in the power supply coil 21. Here, the fixed-side power supply coil 24 and the rotation-side power supply coil 21 function as a power supply unit. In addition,
The magnetic flux formed by the fixed-side power supply coil 24 is indicated by a dotted line in the figure.

The rotation-side signal transmission coil 26 has a groove 23a formed in a part of the rotor
It is wound around an axis perpendicular to. The fixed-side signal transmission coil 27 is opposed to the rotation-side signal transmission coil 26 in a groove 25 a formed in a part of the stator core 25, and is wound around an axis perpendicular to the rotation shaft 22. As a result, for example, the ground fault signal which is a DC signal is
6, a voltage signal representing a ground fault signal is induced in the fixed-side signal transmission coil 27 that is electromagnetically coupled to the coil.

The rotary transformer is not particularly limited as long as it supplies power to the rotary side and transmits a detection signal on the rotary side to the fixed side. In particular, it is suitable for application to the ground fault detection device shown in FIG. When used in a ground fault detection device, the rotating power supply coil 21, the rotor core 23, and the rotating signal transmission coil 26 rotate integrally with the rotating unit I (see FIG. 3). At this time, AC power is supplied to the fixed side power supply coil 24. As a result, the rotary transformer functions as a transformer, and induces AC power in the rotary power supply coil 21. At this time, the rotation-side signal transmission coil 26
For the rotation-side signal transmission coil 26, the amount of interlinkage of the magnetic flux Φ generated by the fixed-side power supply coil 24 is canceled and is always zero, so that (dΦ / dt) = 0. As a result, the induced voltage V becomes zero, and the influence of the magnetic flux Φ by the fixed power supply coil 24 can be eliminated.

When transmitting a ground fault signal from the rotating side,
Since a DC current flows through the rotation-side signal transmission coil 26, a magnetic pole is formed there. The rotation of the magnetic pole induces a voltage in the fixed signal transmission coil 27. This is similar to the state where the synchronous generator is installed. At this time, since the rotor core 23 and the stator core 25 are opposed to each other, the change in the magnetic flux is also close to a sine wave, and the voltage waveform to be induced is also a sine wave. 5
reference. The signal processing in the failure determination unit of (1) becomes easy.
By the way, in the pulse transformer, since the iron cores face each other only for a very short time in one rotation, the magnetic flux changes steeply, and only a pulse-like voltage waveform can be transmitted.
This signal processing becomes complicated.

There is no particular limitation on the winding range of the rotation-side signal transmission coil 26 and the fixed-side signal transmission coil 27.
For example, as shown in FIG.
Is wound around the rotor core 23 in a mechanical angle range of 180 °,
The fixed-side signal transmission coil 27 may be wound around the stator core 25 in a mechanical angle range of 90 °. In this case, it is equivalent to a two-pole generator.

[0015]

As described above in detail with the embodiments, the following effects can be obtained according to the present invention. That is, since a rotary transformer is used as a power source, a constant voltage can be supplied regardless of the operation state of the generator or the like. For this reason, when applied to a ground fault detecting device, it can contribute to miniaturization of a printed circuit board or the like mounted on a rotating unit. On the other hand, as signal transmission, signals can be transmitted reliably without being affected by noise or contamination.
Furthermore, since the structure can be cylindrical or disk-shaped, it is relatively easy to apply to a high-speed rotating machine.
And since they are integrated into one rotary transformer part, the whole structure can be simplified.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, in which (a) is a longitudinal sectional view and (b) is a side view.

FIG. 2 is a side view showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a ground fault detection device of an AC generator according to the related art together with its excitation device.

4A and 4B show a specific example of a case where a rotary transformer is used as a power supply and a signal transmitting means in the ground fault detecting device shown in FIG. 3, wherein FIG. 4A is a circuit diagram thereof, and FIG. And (c) is a longitudinal sectional view thereof.

FIG. 5 shows a specific example in which an AC exciter is used as a power supply and a signal transmission coil is used as a signal transmission means in the ground fault detection device shown in FIG. 3;
Is a circuit diagram thereof, (b) is a plan view showing the extracted signal transmission coil, and (c) is a longitudinal sectional view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Rotation side power supply coil 22 Rotation axis 23 Rotor core 24 Fixed side power supply coil 25 Stator core 26 Rotation side signal transmission coil 27 Fixed side signal transmission coil

Claims (1)

[Claims] In a rotor core that rotates integrally with a rotating shaft, a rotating power supply coil wound around the rotating shaft and a stator core opposed to the rotor core via a gap with respect to the rotating core. A fixed-side power supply coil wound around an axis, a part of the rotor core, a rotation-side signal transmission coil wound around an axis perpendicular to the rotation axis, and a part of the stator core, the rotation shaft And a rotation-side signal transmission coil wound around an axis perpendicular to the fixed portion signal transmission coil so as to face the fixed portion signal transmission coil.