JPH0312080Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a generator equipped with a voltage setting circuit section,
In particular, even if a disconnection occurs in the variable resistor that makes up the voltage setting circuit, the specified output voltage can be maintained.
The present invention relates to a generator equipped with a voltage setting circuit that prevents the voltage adjustment function from being lost.

Generally, a generator having a voltage regulator has a circuit configuration shown in FIG. 1, and its operating principle is as follows. That is, the output voltage of the generator is detected and compared with a reference value, and if the output voltage is larger than the reference value, the off period during which the field current control transistor is turned on and off is increased to reduce the field current. On the other hand, when the output voltage is smaller than the reference value, control operations are performed to increase the field current by increasing the on-period of the transistor to increase the output voltage. The output voltage is maintained within a predetermined setting range.

These operations will be explained using the conventional circuit shown in FIG. In the figure, 1 is a main power generation winding, 2 is an auxiliary winding, 3 is a field winding, 4 and 5 are full-wave rectifiers, 6 is a field current control transistor, and 7 is a control transistor. is connected to Darlington. 8 is a voltage detection transistor, 9 is a diode, 10 is a Zener diode, 11 to 14 are capacitors, 15 to 20 are resistors, 21 is a load, and 22 is a voltage setting circuit section. The main power generation winding 1 and the auxiliary winding 2 are configured to have a phase difference of 90°, and the field winding 3 is wound around a rotor connected to an engine or the like.

In such a configuration, when the field winding 3 is rotated by an engine (not shown), a voltage is induced in the auxiliary winding 2, and this voltage is rectified by the rectifier 4 and passed through the resistor 15 to the transistors 6, 7 is turned on to excite the field winding 3, the output voltage increases more and more. The purpose of diode 9 is field winding 3
This is to prevent generation of undesired high voltage when the voltage is turned off. An output voltage is generated in the winding 1 by the rotating magnetic field and applied to the load 21, and a detection voltage corresponding to the output voltage is applied from the tap P to the rectifier 5 via the voltage setting circuit section 22, and the rectified output voltage is Voltage dividing resistor 18, 19,
20, and the voltage divided thereby appears at point J. In addition, full-wave rectifier 5, resistor 1
8, 19, 20, etc. constitute a voltage detecting section of the voltage regulating circuit. However, at the beginning of the rotation of the generator, the output voltage induced in the winding 1 is small, so the voltage at point J is small and the Zener diode 10, which determines the reference voltage, is in an off state. Therefore, the voltage detection transistor 8 remains off, the control transistor 7 remains on, and the field current control transistor 6 remains on, so current continues to flow through the field winding, resulting in no output. Voltage increases. When the output voltage increases over time and reaches a state exceeding a predetermined set value, tap P.
The detected voltage is applied to the rectifier 5 via the voltage setting circuit section 22, where the rectified and divided voltage exceeds the break point of the Zener diode 10 connected to the J point, and the Zener diode 10 The transistor 8 becomes conductive, and the transistor 8 changes from the off state to the on state. As a result, both transistors 7 and 6 are turned off, so that the current to the field winding 3 is cut off and the output voltage is reduced.

This phenomenon is repeated and the output voltage is kept at a predetermined value, but while the output voltage is kept at a predetermined value, due to the ripple generated at point J,
The transistor 8 repeats on-off operation, and as the on period increases, the field current increases, and as the off period increases, the field current decreases, so that the output voltage is controlled to a predetermined value. .

On the other hand, the voltage setting circuit section 22 is composed of a variable resistor R, and by adjusting the variable resistor R, the voltage value at point J in the figure is changed. That is, by selecting an increased value for the variable resistor R, the average voltage value at point J decreases, the off-period in transistor 8 tends to increase, and as a result, the output voltage remains constant at a higher voltage. It will be controlled so that Also, variable resistance R
By choosing a reduced value, the output voltage can be controlled to be constant at a lower voltage.

Figure 2 shows the characteristics of the output voltage with respect to the output current (load current). range
It is shown as Vmin and Vmax.

The above is an overview of the operation of a generator having a voltage setting circuit section, but the following problems occur in the conventional device described above. That is, if a disconnection occurs in the variable resistor R of the voltage setting circuit section 22, the voltage setting circuit AVC
Since the control input to the zener diode 10 is cut off, the Zener diode 10 is turned off for the entire period, so the transistor 8 is turned off, and the transistors 7 and 6 are turned on, so that the field winding 3 is turned off. Current flows and the output voltage increases undesirably. Therefore, when the generator is unloaded or lightly loaded 21, a high voltage exceeding the permissible range is generated as shown by V ₃ in FIG. 2.

The present invention has been made to solve the above-mentioned drawbacks, and is designed to prevent danger so that the control operation can be performed correctly even if the voltage setting circuit section 22 is disconnected or has some other failure for some reason. The purpose of the present invention is to provide a generator in which a safety circuit is automatically inserted. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of a generator according to the present invention, in which a voltage setting circuit section 22 is provided in a voltage detecting section of a voltage regulating circuit. That is,
The variable resistor of the voltage setting circuit section 22 is connected in parallel to the fixed resistor 18, and the voltage setting circuit section 22 operates normally with a total resistance determined by the resistance value of the fixed resistor 18 and the value of the variable resistor R. In the event of a disconnection or other failure, the fixed resistor 18 is configured to take over and supply the control input. In Fig. 3, each component constituting the voltage regulator circuit AVC, including the main power generation winding 1, auxiliary winding 2, and field winding 3, is exactly the same as in Fig. 1, and is designated by the same reference number. The operation is also similar, so the explanation will be omitted. _V2 in FIG. 2 indicates the output voltage when this danger prevention (safety) fixed resistor 18 is inserted.

The embodiments of the present invention have been described above, but
In the present invention, in order to prevent the field winding current from becoming uncontrollable due to a disconnection or other failure in the voltage setting circuit, the voltage setting circuit is provided within the voltage regulating circuit, and the voltage regulating circuit is provided within the voltage regulating circuit. By configuring it in parallel with the resistor of the voltage detecting section of the circuit, in the event of a disconnection or other failure in the voltage setting circuit section, the resistor of the voltage detecting section functions as a safety resistor and adjusts the voltage. A voltage is kept applied to the control input of the circuit AVC to prevent the terminal voltage of the generator from increasing undesirably.

[Brief explanation of the drawing]

Figure 1 shows the circuit configuration of a generator equipped with a voltage setting circuit according to the prior art, Figure 2 is a characteristic diagram of load current (output current) versus output voltage, and Figure 3 shows the circuit configuration of a generator according to the present invention. An example is shown. In the figure, 1 is the main power generation winding, 2 is the auxiliary winding, 3 is the field winding, 6 is the field current control transistor, 7 is the control transistor, 8 is the voltage detection transistor, and 18 is the voltage dividing resistor. and a resistor that also serves as a safety resistor, 22 represents a voltage setting circuit, and AVC represents a voltage adjustment circuit.

Claims (1)

[Claims for Utility Model Registration] The invention includes a stator around which a main power generation winding is wound and a rotor around which a field winding is wound. A generator comprising a voltage regulation circuit that detects and controls the current flowing through the field winding, and in which the output voltage is controlled, rectifies the output voltage and applies a DC voltage to the input section of the voltage regulation circuit. at least two voltage dividing resistors 18, 19, 20 that supply voltage to the input section of the voltage regulating circuit via the output voltage; and at least one of the voltage dividing resistors 18, 19, 20.
1. A generator equipped with a voltage setting circuit section, characterized in that it has a voltage setting circuit section 22 consisting of a variable resistor R connected in parallel with the voltage setting circuit section 22.