JPH0441750Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention comprises an engine welder, particularly a rotating field type welding generator driven by the engine, and an auxiliary generator driven by the engine. In an engine welder in which the field of the welding generator is excited by a combined current of self-excitation and external excitation, the field of the welding generator is configured to have a non-convex pole type, and , the winding position of the excitation winding that supplies self-excitation to the above-mentioned field is selected, and the armature reaction that occurs in response to the increase in welding current is utilized to improve the characteristics near the rated output. This is related to the engine welder.

Completely separately excited methods and so-called CT compensation methods are known as methods for supplying field current to the field of the welding generator that constitutes the engine welder, but these methods require a separately excited power source or a current transformer. However, there are drawbacks to this method, such as the need for additional equipment, resulting in increased costs and increased space.

One way to improve this is to wind an excitation winding for self-excitation along with the main power generation winding for welding around the stator of the welding generator, and use the output from the excitation winding to self-excite the field. A method has been proposed in which the output from a conventional magnet generator, alternator, etc. is supplied to the engine as a separate excitation component. However, even in this method, as the welding current from the main power generation winding increases, the self-excitation component decreases. For this reason, at a stage before the rated output, there is a tendency for the welding current-output voltage characteristic curve to become distorted and the welding characteristics to deteriorate. Therefore, it is necessary to add a means to increase the self-excitation as the welding current increases, as in the case of the CT compensation method described above.

One of the measures to increase the above self-excitation component is when the welding generator uses a 6-phase half-wave system, and the voltage waveform of each phase of the 6-phase half-wave is delayed by 90 degrees in electrical angle. It was considered to increase the self-excitation by winding the excitation winding in a position where the welding current is increased and utilizing the armature reaction that occurs as the welding current increases.

The present invention aims to bring the welding characteristics close to the ideal type near the rated output by considering the winding position of the excitation winding so as to effectively utilize the armature reaction. This will be explained below with reference to the drawings.

Figure 1 shows the configuration of an embodiment of the present invention, which is illustrated to make it easier to understand the relationship between the main power generation winding of a welding generator, the excitation winding for self-excitation, and the field. An explanatory diagram illustrating the characteristics of the engine welder of the present invention is shown.

In Figure 1, 1 is the engine, 2 is the magnet generator, 3 is the rotating field of the welding generator, 4 is the field winding, 5 is the stator of the welding generator, 6U1 to 6
U3 and 6V1 to 6V3 are main power generation windings, 7 is an excitation winding for self-excitation, S1 to S24 are stator slots, 8 to 13 are diodes, 14 are welded parts, 15 and 16 are rectifiers, respectively.
17 represents a variable resistor, and 18 represents an output terminal for a three-phase AC power supply.

The stator 5 of the welding generator has an electrical angle of 60° to each other.
Main power generation windings 6U1 to 6U3 and 6V1 to 6V3, which are phase-shifted, are wound as shown in the figure, and the induced voltage in each main power generation winding 6 is rectified by six-phase half-wave rectification by diodes 8 to 13. A DC voltage is applied to the welding part 14. Further, an excitation winding 7 for self-excitation is wound on the stator 5. In the illustration, for example, the N pole of the rotating field 3 is arranged in the direction in which the slot numbers decrease from the slot number 24 shown in FIG. 1, that is, slot number 23, slot number 22, .
It is assumed that the robot moves to each position of... For example, assume that the magnetic center of the main power generation winding 6U1 is located at the boundary between slot numbers 7 and 8, and that the magnetic center of the excitation winding 7a is located at the boundary between slot numbers 5 and 6. It is assumed that there is. If this expression using the magnetic center is adopted, the excitation winding 7 is the main power generation winding 6U1 to 6U3 and 6V1 to 6V3.
The windings are wound at the stator slot position so as to obtain a magnetic center delayed in electrical angle from more than 0° to 30° or less with respect to each magnetic center. That is, for example, the illustrated excitation winding 7a is wound at a slot position having a magnetic center delayed by 30 degrees in electrical angle with respect to the magnetic center of the main power generation winding 6U1. Then, the main power generation winding 6U1 is
When supplying the welding current, the welding current acts to increase the voltage induced in the excitation winding 7a due to the armature reaction caused by the welding current.

Assuming that the welding current has a sinusoidal waveform, the armature reaction described above is such that, for example, the excitation winding 7a is at 90° with respect to the voltage induced in the main power generation winding 6U1.
It works most strongly when it is in a delayed position, that is, when the magnetic center of the excitation winding and the magnetic center of the main power generation winding are aligned. However, the reason why it is delayed by 30 degrees from the magnetic center as in the case of the illustrated embodiment will be explained later.

The voltage induced in the excitation winding 7 is passed through the rectifier 16
The rectified signal is rectified by and applied to the field winding 4.
This supplies self-excitation to the field winding 4. On the other hand, the voltage from the magnet generator 2 originally provided in the engine 1 is rectified by the rectifier 15 and applied to the field winding 4 . This supplies the field winding 4 with an externally excited component.

The rotating field 3 has a cylindrical non-convex pole configuration, and generates magnetic fluxes with polarities as indicated by N and S in the figure.

As stated at the beginning of this specification, a field current that is a combination of the self-excitation from the excitation winding 7 and the other excitation from the magnet generator 2 is applied to the field winding 4 of the welding generator. A supply method has been proposed. However, even in this case, it is necessary to eliminate by some means an undesirable phenomenon that occurs as the welding current increases, that is, a tendency to reduce self-excitation. Therefore, the inventors of the present invention attempted to increase the magnetomotive force acting on the excitation winding 7 by utilizing the armature reaction caused by the welding current, thereby suppressing the above-mentioned decreasing tendency of self-excitation.

The one-dot chain line P shown in FIG. 2 represents the characteristic when the excitation winding 7 is disposed at a slot position having a magnetic center at an electrical angle of 0° with respect to the magnetic center of the main power generation winding. That is, the characteristics are shown when, for example, the excitation winding 7a is wound between the slots S6 and S9 so that the magnetic center of the excitation winding coincides with the magnetic center of the main power generation winding 6U1. Hereinafter, for the sake of simplicity, the case where the excitation winding 7a is wound between slots S6 and S9 will be referred to as center position winding, and it will be delayed by 15 degrees from the center position winding (the pole of field 3 is 15° shift position winding refers to the case where the winding is performed between the positions (reaching with a time delay), that is, slots S5 and S8, and is called 15° shift position winding. The case where the winding is done between the positions is called 30° shift position winding.

The dotted line Q shown in FIG. 2 shows the characteristics in the case of winding at the above 15° shift position, and the solid line R shown in FIG.
The characteristics in the case of shift position winding are shown.

If the voltages induced in the main power generation windings 6U1 to 6U3 and 6V1 to 6V3 have a correct sinusoidal waveform, the above-mentioned armature reaction will work most effectively in the case of the above-mentioned center position winding, and self-excitation will occur. increase. However, even when a non-convex pole type rotating field 3 is used as shown in FIG. 1, when the welding current increases, the sine waveform is distorted, as shown by the chain line P in FIG. The self-excitation tends to decrease in the vicinity before reaching the rated output, and as shown in the illustrated welding characteristic P, so-called entrainment occurs in the vicinity where the output voltage intersects the indicated welding voltage (20 + 0.05 I) volts. As a result, the arc tends to be extinguished in an undesirable manner.

On the other hand, in the case of 15° shift position winding and 30°
In the case of shift position winding, the above-mentioned winding occurs only when the output voltage becomes a value lower than the welding voltage, as shown in the welding characteristics Q and R shown in FIG. 2, and stable welding becomes possible. This can be considered to be because the sine waveform is distorted, and the apparent phase shift due to the distortion is compensated for in advance by winding at a 15° shift position or winding at a 30° shift position. Note that while current is flowing through the main power generation winding 6U1, other main power generation windings 6V2, 6U2, 6V3, 6U3,
No current flows through 6V1 (due to the presence of diodes 8 to 13). For this reason, the main power generation winding 6U
Originally, the armature reaction caused by the magnetic flux caused by the current flowing through the excitation winding 7
It works the most when a is at the center position.
Therefore, when considering the armature reaction caused by the current flowing through the main power generation winding 6U1, it is only necessary to consider the deviation from the center position. In the case shown in Fig. 1, the excitation winding 7a is viewed from the above center position.
It is located 30° behind.

Moreover, when the excitation winding 7a is at the center position,
As described above, the characteristic is shown by the chain line P shown in FIG. In addition, if the excitation winding 7a is at a position later than the 30° delayed position, the intersection with the straight line (20 + 0.05I) will be further leftward than the solid line R shown in Figure 2, and when driving The welding current I is smaller than that of the solid line R.

As explained above, according to the present invention, in an engine welder that supplies a field current by combining the self-excitation from the output from the excitation winding and the external excitation from a dynamo, etc., the excitation winding By selecting the winding position, it becomes possible to efficiently compensate for the decrease in self-excitation near the rated output, making it possible to perform stable welding.

[Brief explanation of the drawing]

FIG. 1 shows the configuration of an embodiment of the present invention, and FIG. 2 shows an explanatory diagram illustrating the characteristics of the engine welder of the present invention. In the figure, 1 is the engine, 2 is the magnet generator, 3 is the rotating field of the welding generator, 4 is the field winding, 5 is the stator of the welding generator, 6U1 to 6U3 and 6
V1 to 6V3 are the main power generation windings, 7 is the excitation winding,
S1 to S24 are stator slots, 8 to 1
3 is a diode, 14 is a welding part, 15, 16
17 and 18 respectively represent a rectifier, a variable resistor, and an output terminal for a three-phase AC power supply.

Claims (1)

[Claims for Utility Model Registration] A rotating field type welding generator driven by an engine and an auxiliary generator driven by the engine are provided, and the main winding arrangement of the welding generator is It is wired to generate a 3-phase, 6-phase, half-wave rectified DC output as a welding power source, and is wound on the generator stator with respect to the field winding of the welding generator. In the engine welder configured to combine and supply the DC output from the self-exciting excitation winding and the DC output from the auxiliary generator, the magnetism of the main winding of the welding generator is The excitation winding is wound so that the magnetic center of the excitation winding is shifted one or two slot pitches behind the rotational direction of the rotor with respect to the target center, and the field winding is also wound. An engine welder characterized by having a non-convex pole structure.