JPH0323834Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a commutator generator that obtains induction generator characteristics using a three-phase AC commutator rotated by the prime mover of a small water turbine or windmill. In particular, the present invention relates to an excitation switching circuit for a commutator generator for excitation switching that takes advantage of induction generator characteristics.

[Prior art and its problems]

Conventionally, synchronous generators have been used as generators in small hydroelectric power generators, etc., so in order to keep the frequency of the generated voltage constant, the water wheel of the prime mover requires a guide vent or speed governor, which reduces the rotational speed of the prime mover. A complicated rotational speed control device was required to control the rotation speed to a predetermined value.

In view of these points, the applicant is currently proposing a utility model registration application for ``Commutator Generator'' (December 11, 1980).

This uses a three-phase AC commutator machine (hereinafter simply referred to as a commutator machine) instead of a conventional synchronous generator to take advantage of the characteristics of an induction generator, so it is a precise speed governor that suppresses the rotational speed of the prime mover. This realizes a device with a simple configuration in which the

Therefore, in order to take advantage of the above-mentioned induction generator characteristics, it is necessary to synchronize the induction generator with good timing. That is, the commutator generates positive rotational force in the motor region and negative rotational force in the generator region. Due to the generation of this rotational force, a large current may sometimes flow through the commutator machine, causing problems such as equipment damage.
For this reason, it is generally necessary to take measures such as inserting a current suppression resistor in series with the secondary winding of the commutator.

[Structure of the idea]

The present invention was developed by focusing on the above-mentioned points, and when the rotation speed of the commutator machine reaches a point corresponding to the operating position of the limit switch for detecting the brush position of the commutator machine, the commutator machine is energized. The present invention provides an excitation start-up circuit for a commutator generator which is made to act as an induction generator by giving the following. Hereinafter, the present invention will be explained with reference to FIGS. 1 and 2.

Figure 1 is a conceptual diagram showing the main structure of the present invention.
2 is a small water turbine which is an example of a small water turbine, 2 is an increase/decelerator, 3 is
is a commutator machine, 4 is a brush roller, 5 is an operating motor,
6 is a control amplifier that drives the operating motor 5, 7 is a switch, and 8 is a three-phase external power supply. Further, 9 is a limit switch for detecting the brush rocker position, 10
is a speed detector that detects the rotation speed of the commutator machine 3;
11 is a speed detection circuit.

In FIG. 1, a commutator machine 3 is connected to a small water wheel 1 via an increase/decrease gear 2, and the rotational force of the small water wheel 1 drives the commutator machine 3 as an induction generator.
Here, the commutator machine 3 has a brush rocker 4,
It is equipped with an operating motor 5 and a control amplifier 6, and exhibits induction generator characteristics by displacing the brush rocker 4 by the control amplifier 6. Further, the commutator 3 is connected to a three-phase external power source 8 via a switch 7. By using the commutator machine 3 as an induction generator, electric power of a constant frequency can be generated even if the rotational speed of the small water turbine 1 changes by simply supplying excitation reactive power from the three-phase external power source 8. The operating characteristics of this commutator machine 3 are shown as shown in FIG.

FIG. 2 shows the relationship between the rotational force and rotational speed of the commutator machine, where T is the rotational force and N is the rotational speed.
That is, in FIG. 2, the positive direction of the rotational force T is the electric motor region, and the negative direction of the rotational force T is the generator region. Here, characteristic lines as illustrated are obtained at positions θ ₁ , θ ₂ , and θ ₃ of the brush rocker 4 in the high speed range, medium speed range, and low speed range.

In the functions shown in FIGS. 1 and 2, for example, when the brush rocker 4 is at the position θ ₃ and the switch 7 is closed at the rotational speed N ₁ of the commutator 3, a positive rotational force T is generated. produces ₁ . On the other hand, when the switch 7 is closed at the rotation speed N ₃ at the position θ ₃ ,
Generates negative rotational force T ₂ . As mentioned above, this causes a large current to flow through the commutator 3, causing problems. Then, when the switch 7 is closed at the rotational speed N ₂ at which the rotational force is zero when the brush rocker 4 is at the position θ ₃ , the current that generates the rotational force does not flow through the commutator unit 3, and the excitation circuit is smoothly turned on. I can do it.

Therefore, the present invention is designed to provide a limit switch 9, a speed detector 10, and a speed detection circuit 11 as shown in FIG. It is something to do.

That is, in FIGS. 1 and 2, for example, when the brush rocker 4 is at position θ ₃ , the brush rocker position is detected by the limit switch 9, while the rotational speed N of the commutator machine 3 is monitored, and the commutator machine 3 is Small water wheel 1
When the rotation speed increases, the speed detection circuit 11 which obtains the output of the speed detector 10 detects the rotation speed N ₂ . After detecting the position θ ₃ and rotational speed N ₂ , the switch 7 is activated by the action of the speed detection circuit 11.
It closes the circuit. Therefore, when the switch 7 is closed, the rotational force T in FIG. 2 is zero, and
The current for generating rotational force also becomes zero, and there is no rush of a large current into the commutator machine 3, so that the generator characteristics can be smoothly obtained as described above.

[Effect of idea]

As explained above, according to the present invention, it is possible to provide a device with a simple configuration that can exceptionally perform excitation input to take advantage of the induction generator characteristics using a commutator machine.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram showing the main structure of the present invention, Figure 2
The figure is a characteristic diagram showing the relationship between rotational force and rotational speed of a commutator machine shown for explaining the present invention. 1...Small water wheel, 3...Three-phase AC commutator machine (commutator machine), 4...Brush roller, 5...Operation motor,
6... Control amplifier, 7... Switch, 8... Three-phase external power supply, 9... Limit switch, 10... Speed detector, 11... Speed detection circuit, T, T ₁ , T ₂ ...
... Rotating force, N, N ₁ , N ₂ , N ₃ ... Rotating speed.

Claims (1)

[Scope of utility model registration request] A three-phase AC commutator machine 3 rotated by a prime mover such as a water wheel or a windmill, an operating motor 5 that moves the brush position of the three-phase AC commutator machine 3, and the operating motor 5
In this commutator generator, the three-phase AC commutator machine 3 is in a brush rocker position having a predetermined rotational speed. A limit switch 9 for detecting that the rotation speed of the three-phase AC commutator machine 3 has been reached and a speed detector 10 for detecting the rotation speed of the three-phase AC commutator machine 3 are provided, and the zero rotational force of the three-phase AC commutator machine 3 specified by the limit switch 9 is provided. An excitation turning-on circuit for a commutator generator, characterized in that it is configured to detect a rotational speed corresponding to the rotational speed and apply excitation to the three-phase AC commutator 3.