JPH09243694A - Method for testing impulse of transformer for rectifier with built-in reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately determine whether or not a defect exists in a device to be inspected by applying test voltage with a voltage adjusting reactor grounded via a resistor. SOLUTION: A transformer for a rectifier comprises a primary coil T and a secondary coil (t), wherein a voltage adjusting reactor VCR is connected in series with the secondary coil (t), and its output terminal to , is grounded via a resistor R. Since magnitude of current flowing in the voltage adjusting reactor VCR is limited by the resistor R, an iron core F may not be saturated, and waveforms of IR observed by a current shunt S may not change due to magnitude of impulse voltage. As a result, whether or not a defect exists in the transformer for rectifier can be immediately and correctly determined.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impulse test method for a rectifier transformer used in an AC / DC converter, and more particularly to a test method for preventing distortion of a current waveform when the apparatus is normal.

2. Description of the Related Art An AC-DC converter is composed of a rectifier transformer and a rectifier. The rectifier transformer converts an AC high voltage on the power supply side into a low voltage required on the DC side, and this low voltage. Is output to the rectifier via the voltage adjustment reactor. Upon receiving the output of the rectifier transformer, the rectifier converts it into direct current and outputs it to the load side. The rectifier transformer includes an AC-side primary winding and a DC-side secondary winding, and a voltage adjustment reactor is connected to the secondary winding. The voltage adjustment reactor is equipped with a control winding, and the output voltage to the rectifier side is finely adjusted. Since the rectifier transformer is a high-voltage device, it is separated from the rectifier, and a high-voltage insulation test such as an impulse test is performed with the voltage adjustment reactor included. 13 and 14 are test circuit diagrams showing a conventional impulse test method for a transformer for a built-in reactor rectifier. FIG. 13 is a test circuit diagram of the primary winding side.
4 shows a test circuit diagram of the secondary winding side and the voltage adjustment reactor. The winding configuration of the rectifier transformer and the test method will be described with reference to this circuit diagram. In FIG.
The rectifier transformer includes two primary windings T1 and T2, and the respective primary windings T1 and T2 are connected in a star shape, and the terminals 1U, 1V and 1W are connected to each other. Further, in FIG. 14, the secondary windings t3 and t4 are primary windings T
It is a winding wire corresponding to 1 and is connected in a triangular shape. on the other hand,
The secondary windings t1 and t2 are windings corresponding to the primary winding T2 and are star-connected. Two voltage adjusting reactors VCR are respectively connected to the terminals u1, v1, w1, ... Of the secondary windings t1 to t4, and a total of 24 output terminals t0 are provided. A rectifier (not shown) is connected to each of the terminals t0. Two voltage adjusting reactors VCR are connected to the respective terminals of the secondary winding for connecting the rectifying elements to the terminal t0 in different directions. For example, the voltage adjustment reactor V
The cathode side of the rectifying element in one of the CRs is connected, and the other side is connected to the anode side of the other rectifying element. Further, in FIG. 14, the voltage adjustment reactor VCR is one in which a main conductor penetrates the inside of a cylindrical iron core in the axial direction thereof. One end of the main conductor is connected to each terminal of the secondary windings t1 to t4, and the other end of the main conductor is connected to the output terminal t0. Although not shown in FIG. 14, control windings are wound around the iron core of the voltage adjustment reactor VCR. In the impulse test, as shown in FIG. 13, a negative impulse voltage V is applied to the terminals 1U of the primary windings T1 and T2, and the terminals 1V and 1W of the primary windings T1 and T2 are applied.
Is grounded. A current shunt S is interposed between the terminals 1V and 1W and the ground E, and a current waveform flowing when the impulse test voltage V is applied is observed. The test circuit of FIG. 13 is an example of an impulse test, and the terminals 1V and 1W are similarly grounded at the other terminals and the impulse test voltage V is applied. In each test, a positive impulse test voltage V is also applied. On the other hand, the secondary windings t1 to t4 are grounded at the output terminal t0 as shown in FIG. FIG. 15 is a test circuit diagram collectively showing the circuits of FIGS. 13 and 14. A negative impulse test voltage V is applied to the terminal 1U of the tester TR, which is a rectifier transformer, and the terminals 1V and 1W are grounded via the current shunt S. On the other hand, of the 24 output terminals t0, 12 are grounded. U1P and u3 are connected to the output terminal t0.
Symbols such as P, ... Are marked. This symbol is the first
The letter and the second letter indicate the terminals of the secondary winding, and the third letter indicates the direction of the rectifying element. If the third character is P, the output terminal t0 is connected to the anode side of the rectifying element, and if the third character is N, the output terminal t0 is connected to the cathode side of the rectifying element. For example, in the symbol u1P, the terminal u1 of the secondary winding t1 is connected to the anode side of the rectifying element via the voltage adjustment reactor VCR. In the test circuit of FIG. 15, it has been described above that the current waveform is observed by the current shunt S when the impulse test voltage V is applied, but at the same time, the voltage waveform of the impulse test voltage V is also not shown. Observed by the device. The impulse test is a test for checking whether or not the EUT can withstand a specified voltage having a specified peak value. When the EUT has a dielectric breakdown, an abnormal sound is usually heard and the voltage waveform changes to zero on the way, so that it is possible to know whether the EUT has withstood the specified voltage. However, if the inside of the EUT is only partially broken down, no abnormal sound is heard and the voltage waveform may not change at all. Therefore, in the impulse test, a reduced voltage lower than the specified voltage is applied in advance before the specified voltage is applied. The waveforms of the currents that flow when the reduced voltage and the specified voltage are applied are compared with each other. If the EUT is normal, there is no change in both current waveforms (the current levels are different), but if partial internal breakdown occurs, the current waveforms will be different from each other. You can know. This is because the impedance in the internal circuit changes abruptly when partial insulation breakdown occurs.

However, in the conventional method as described above, the current waveforms of the reduced voltage and the specified voltage may not be the same even if the EUT is normal, and the EUT malfunctions. There is a problem that it becomes difficult to judge. That is, even if the EUT is normal, the current waveform changes as the impulse test voltage is repeatedly applied,
In some cases, it was judged as if the EUT failed. FIG. 16 is a voltage / current waveform diagram according to a conventional impulse test method. (A) is a waveform when a reduced voltage is applied, and (B), (C) and (D) are waveforms when a specified voltage is applied. . In the test circuit of FIG. 15, (1 × 50)
A test voltage V of negative standard lightning impulse of μs was applied. In each figure, the upper waveform is the applied voltage waveform and the baseline (zero line) of the voltage, and the lower waveform is the current waveform observed in the current shunt S (FIG. 15) and its current baseline. First, the reduced voltage was applied, and then the specified voltage was sequentially repeated and applied multiple times. (A) is what was observed when the reduced voltage was first applied,
(B), (C), and (D) are observed in the order of application of the specified voltage. In FIG. 16, (A) and (B) have the same current waveform, but (B),
A change is seen in the current waveform as (C) and (D). This makes it impossible to determine whether or not the EUT has failed. In such a case, disassembling the EUT to check whether the inside is damaged or applying an AC voltage to check whether the EUT is normal or not is done, and it takes time to judge whether the test is successful or not. Or, it was not possible to make an accurate judgment. An object of the present invention is to provide a test method in which the current waveform of the reduced voltage and the current waveform of the specified voltage are always the same when the EUT is normal.

In order to achieve the above object, according to the method of the present invention, the primary winding is an AC side winding, and the secondary winding is a DC side winding. An impulse test method for a reactor built-in rectifier transformer, in which the output terminal of the secondary winding is connected to a rectifier via a voltage adjustment reactor, and the control winding is wound around the iron core of the voltage adjustment reactor. Saturate the core of the voltage adjustment reactor in the method in which the secondary winding is grounded via the voltage adjustment reactor, and the impulse test voltage is applied to one end of the primary winding with the other end of the primary winding grounded. It is advisable to apply the test voltage in a state in which the test voltage is not applied. The reason is as follows. It was found that the current waveform of the reduced voltage and the current waveform of the specified voltage do not become the same even when the EUT is normal because the iron core of the voltage adjustment reactor is saturated. FIG. 17 is a principle diagram of a conventional test circuit (FIG. 15). This diagram is a simplified equivalent circuit diagram of the test circuit of FIG. The rectifier transformer is composed of a primary winding T and a secondary winding t, and a voltage adjusting reactor VCR is connected in series to the secondary winding t. Since all terminals of the secondary winding t are grounded via the voltage adjusting reactor VCR, both ends of the secondary winding T are short-circuited via the voltage adjusting reactor VCR in terms of an equivalent circuit. FIG.
In, the impulse test voltage V is applied between the terminal 1U of the primary winding T and the ground E, and the current I flowing through the current shunt S is observed. A voltage is induced in the secondary winding t by this current I, and the current I1 flows through the voltage adjustment reactor VCR grounded via the output terminal t0. FIG. 18 is a characteristic diagram showing a magnetic state of the iron core of the voltage adjustment reactor according to the conventional test circuit.
The solid line M is the characteristic of the voltage adjustment reactor core itself,
The positive side is saturated at point Q1 and the negative side is saturated at point Q2. In FIG. 18, the magnetic state of the iron core F (FIG. 17) of the voltage adjustment reactor is at the origin O before the start of the test. When the iron core F is magnetized by the current I1, its magnetic state follows the path indicated by the dotted line M1. In that case, the current I1
There are two cases in the magnetic state of the iron core F depending on the size of. The first case is when the iron core F is magnetized to the point P. In that case, when the current I1 becomes zero,
The magnetic state of the iron core F comes to the position of the point P1 and the residual magnetism remains. In the second case, the iron core F has a point Q1.
This is the case where the magnetization is performed up to the saturation region Q. In that case, when the current I1 becomes zero, the magnetic state of the iron core F changes to the point P.
The residual magnetism remains at the position 2. In the first case, since the magnetic characteristic is almost linear as indicated by the dotted line M1, no change is seen in the waveform of the current I and no problem occurs. However, in the second case, since the iron core F is saturated from the point Q1, the impedance of the voltage adjustment reactor VCR changes and the waveform of the current I changes. For example, assuming that the first case corresponds to the application of the reduced voltage V and the second case corresponds to the application of the specified voltage V, the observed current waveforms are different from each other, and the test device is normal. It is suspected that an internal failure has occurred. Even if the first case corresponds to the application of the specified voltage V, the next test voltage V
Since the application of the voltage starts from the point where the residual magnetism at the point P1 remains, if the voltage V is applied several times, the iron core F becomes the saturation region Q.
May be magnetized and the current waveform may change. From the above, the inventors use the method of applying the test voltage in a state in which the iron core of the voltage adjustment reactor is not saturated,
It was discovered that the current waveform of the reduced voltage and the current waveform of the specified voltage are always the same when the EUT is normal. FIG.
It is a characteristic view which shows the magnetic state of the iron core of the voltage adjustment reactor for demonstrating the method of this invention. The scales on the horizontal axis and the vertical axis are the same as those in FIG. 18, and the solid line M represents the characteristics of the iron core itself of the voltage adjustment reactor. The above-described method is to suppress the magnetic flux of the iron core within the unsaturated region B0 that follows the path indicated by the dotted line M2 in the magnetic characteristic of the solid line M without fail.
In order to prevent the iron core from being saturated, there is a method of lowering the magnetic flux density of the iron core of the voltage adjusting reactor, but this makes the iron core thick and the physique of the voltage adjusting reactor becomes large. As a method of not saturating the iron core of the voltage adjustment reactor without lowering the magnetic flux density of the iron core, the inventors have found a method of applying a test voltage with the secondary winding being grounded via the voltage adjustment reactor and a resistor. . FIG.
FIG. 6 is a principle diagram of a test circuit performed by interposing a resistor for explaining the method of the present invention. Voltage adjustment reactor VC
The R output terminal t0 is grounded via a resistor R. Since other configurations are the same as those in FIG. 17, the same parts are designated by the same reference numerals, and detailed description thereof will not be repeated here. Current I2 flowing through voltage regulator reactor VCR
Is limited by the resistance R, the iron core F is not saturated, and the waveform of the current IR observed by the current shunt S is not changed by the magnitude of the impulse voltage. In this way, by inserting the resistance only during the impulse test, the current flowing through the voltage adjusting reactor can be suppressed and the iron core can be prevented from being saturated. Further, as another method of not saturating the iron core of the voltage adjustment reactor, after applying a saturation magnetic field having a polarity opposite to the polarity magnetized by the test voltage to the iron core of the voltage adjustment reactor, once returning the magnetic field of the iron core to zero, The inventors have also found a method of applying a test voltage subsequently to this. FIG.
FIG. 4 is a characteristic diagram showing a magnetic state of an iron core of a voltage adjustment reactor for explaining the method of the present invention. The scales of the horizontal axis and the vertical axis are the same as in FIG. 1, and the solid line M is the characteristic of the iron core itself of the voltage adjustment reactor. In the magnetic characteristic of the solid line M, the above-described method magnetizes the iron core of the voltage adjustment reactor to the negative polarity side once and reaches the position of the point Q2 where the magnetic state follows the solid line M3 and is saturated on the negative polarity side. Therefore, the current is set to zero and the magnetic state is traced along the solid line M4 to obtain the point P.
Reach position 3. If the impulse test is performed when the magnetic state is at the point P3, the unsaturated region B0 along the dotted line M2
You can use the entire width of. For example, even if the regions B1 and B2 are used by applying the reduced voltage or the specified voltage, respectively, the width of the unsaturated region B0 is wide, and therefore the current waveform does not change. In such a method, it is preferable to apply a saturation magnetic field having an opposite polarity each time the test voltage is applied. Depending on the test voltage level, the impulse test voltage may be applied several times in succession. In short, it does not matter if the magnetic state of the iron core in the test is within the unsaturated region B0. However, the magnetic state of the iron core is always shown in Fig. 3 every time the test voltage is applied.
If it is returned to the state of point P3 of
It can be used from 3 to the full width, there is no failure of the test that the iron core is in the saturated region, and wasteful time called retest can be saved. As one method of applying a saturation magnetic field having an opposite polarity to the iron core of the voltage adjustment reactor, it is preferable to apply an impulse voltage having a polarity opposite to the polarity of the test voltage to one end of the primary winding. Further, as another method of applying a saturation magnetic field of opposite polarity to the iron core of the voltage adjusting reactor, a direct current may be passed through the control winding. According to another method of the present invention, the primary winding is an AC side winding, the secondary winding is a DC side winding, and the output terminal of the secondary winding is connected via a voltage adjustment reactor. It is an impulse test method for a transformer with built-in reactor that is connected to a rectifier and a control winding is wound around the iron core of the voltage adjustment reactor. It is advisable to apply the test voltage in a saturated state on the same polarity side. The reason is as follows. FIG. 4 is a characteristic diagram showing a magnetic state of the iron core of the voltage adjustment reactor for explaining still another method of the present invention. The scales of the horizontal axis and the vertical axis are the same as in FIG. 1, and the solid line M is the characteristic of the iron core itself of the voltage adjustment reactor. In the magnetic characteristic of the solid line M, the above-mentioned method further magnetizes the magnetic field from the point Q1 and extends the range along the dotted line M5, that is,
This is a method of always maintaining the magnetized state of the iron core in the saturated region H0. Within this saturation region H0, the impedance of the voltage adjustment reactor does not change, and the observed current waveform does not change between the case of the reduced voltage and the case of the specified voltage. In order to maintain the magnetized state of the iron core in the saturation region H0, there is a method of previously winding a winding for saturation of the iron core. The iron core can be saturated if it is run.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, examples in which the method of the present invention is used will be introduced. FIG. 5 is a test circuit diagram showing an impulse test method according to the embodiment of the present invention. FIG.
The output terminal t0 of the voltage adjusting reactor is grounded via the resistor R according to the principle diagram of FIG. Others are shown in Fig. 1.
Same as 5. FIG. 6 shows the voltage by the test circuit of FIG.
It is a current waveform figure, (A) is a waveform at the time of application of a reduction voltage, (B), (C) and (D) is a waveform at the time of application of a regulation voltage, respectively. In each drawing, the arrangement of the voltage waveform, the current waveform, and the base line is the same as in the case of FIG. First, the reduced voltage was applied, and then the specified voltage was sequentially applied. (A) is observed when the reduced voltage is first applied, and (B), (C), and (D) are observed in the order of application of the prescribed voltage. In FIG. 6, it can be seen that there is no difference in the current waveforms of (A) to (D). By interposing the resistor R, the iron core of the voltage adjustment reactor is not saturated, and it becomes possible to immediately and accurately determine whether the rectifier transformer TR has a failure. Figure 7
6A and 6B are voltage / current waveform diagrams according to an impulse test method according to different embodiments of the present invention, in which (A) is a waveform when a reduced voltage is applied, and (B), (C), and (D) are when a specified voltage is applied. Is the waveform of. In each figure, the arrangement of the voltage waveform, the current waveform, and the base line is the same as in the case of FIG. Figure 7
The test circuit of FIG. (A) is obtained by first applying an impulse voltage having a positive polarity and the same level and waveform as the reduction voltage, and then applying a regular reduction voltage having a negative polarity. Further, in (B), after the normal reduction voltage is applied, a positive polarity impulse voltage having the same level and waveform as the specified voltage is applied, and then the negative polarity specified voltage is applied. It was obtained by Hereinafter, (C) and (D) are obtained in the same order by applying an impulse voltage of opposite polarity before applying the specified voltage. That is, when the first positive polarity impulse voltage is applied, the iron core of the voltage adjustment reactor is magnetized along the solid lines M3 and M4 as described in FIG. 3, and in the state of the point P3, the regular reduction voltage or the specified voltage is applied. Has been applied. In FIG.
It can be seen that there is no difference in the current waveforms of (A) to (D). By applying the reverse polarity impulse voltage in advance, the iron core of the voltage adjustment reactor is not saturated, and it becomes possible to immediately and accurately determine whether or not there is a failure in the rectifier transformer TR. FIG. 8 is a test circuit diagram showing an impulse test method according to a further different embodiment of the present invention. What is different from FIG. 15 is that the output terminal t0 having a different sign is grounded and is not shown. The only point is that a direct current is applied to the control winding. FIG.
9 is a test circuit diagram showing a connection state of control windings not shown in the test circuit of FIG. 8. FIG. Voltage regulation reactor VCR interposed between the secondary winding t and the output terminal t0
Three control windings G are wound around each iron core.
One of the control windings G of each voltage regulation reactor VCR is connected in series with each other, and the DC power supply A1 is connected to both ends of this series circuit.
Are connected. The polarity direction of the DC current supplied to the control winding G by the DC power supply A1 is magnetized in the opposite direction to the direction in which the iron core of the voltage adjusting reactor VCR is magnetized by the application of the regular reduced voltage or the regulated voltage in the impulse test. It has become so. Before each impulse voltage, a direct current is made to flow through the control winding G to magnetize the iron core of the voltage adjusting reactor VCR. That is, by applying a direct DC voltage in advance, each of the iron cores of the voltage adjusting reactor has a solid line M3, as described in FIG.
It is magnetized along M4, and a regular reduction voltage or a specified voltage is applied in the state of point P3. It should be noted that although the primary winding is not shown in FIG. 9, the primary winding has the same configuration as in FIG. FIG. 10 is a voltage / current waveform diagram by the test circuit of FIGS. 8 and 9, where (A) is a waveform when a reduced voltage is applied, and (B) and (C) are waveforms when a specified voltage is applied. In each figure, the arrangement of the voltage waveform, the current waveform, and the base line is the same as in the case of FIG. In (A), the DC power supply A1 in FIG. 9 is first used, and then the DC power supply A1 is used.
It is obtained by applying a regular reduced voltage in the state of being cut off. In addition, (B) shows the DC power supply A1 of FIG. 9 again after the regular reduction voltage is applied in (A).
Is obtained, and then a normal specified voltage is applied in a state in which the DC power supply A1 is cut off. Further, in (C), after the normal specified voltage is applied in (B), the DC power supply A1 of FIG. 9 is used again, and then the normal specified voltage is applied in the state where the DC power supply A1 is cut off. It has been obtained. In FIG. 10, (A)
It can be seen that there is no difference in the current waveforms of (C) to (C). By applying the DC voltage in advance, the iron core of the voltage adjustment reactor is not saturated, and it becomes possible to immediately and accurately determine whether the rectifier transformer TR has a failure. FIG. 11 is a test circuit diagram showing an impulse test method according to still another embodiment of the present invention.
The only difference from FIG. 9 is that the polarity of the DC power supply A2 is opposite to that of the DC power supply A1. Also, the connection of the primary winding and the secondary winding is the same as in FIG. The polarity direction of the DC current supplied to the control winding G by the DC power supply A2 is magnetized in the same direction as the direction in which the iron core of the voltage adjusting reactor VCR is magnetized by the application of the regular reduced voltage or the specified voltage in the impulse test. It is like this. When each impulse voltage is applied, a direct current is always passed through the control winding G, and all the iron cores of the voltage adjustment reactor VCR are always kept in a saturated state. That is, as described with reference to FIG. 4, each of the iron cores of the voltage adjusting reactor is magnetized by the application of the DC voltage, and the regular reduction voltage or the specified voltage is applied in the state of the point Q3. FIG. 12 is a voltage / current waveform diagram by the test circuit of FIG. 11, where (A) is a waveform when a reduced voltage is applied, and (B), (C), and (D) are waveforms when a specified voltage is applied. . In each figure, the arrangement of the voltage waveform, the current waveform, and the base line is the same as in the case of FIG. In the state where the DC power supply A2 of FIG. 19 is utilized, (A) is obtained by first applying a regular reduced voltage. (B)
(A) is obtained after the regular reduction voltage is applied, and (C) and (D) are obtained by sequentially applying the regular specified voltage after (B). . In FIG. 12, it can be seen that there is no difference in the current waveforms of (A) to (D). By constantly applying the DC voltage, the iron core of the voltage adjusting reactor is in a saturated state, and it becomes possible to immediately and accurately determine whether the rectifier transformer TR has a failure.

EFFECT OF THE INVENTION A method of applying a test voltage so as not to saturate the iron core of the voltage adjusting reactor, specifically, applying the test voltage with the voltage adjusting reactor grounded via a resistor, or in advance. By applying the test voltage after applying the reverse polarity impulse voltage or DC voltage, it becomes possible to immediately and accurately determine the presence or absence of a failure of the EUT, shortening the test time and improving the reliability. Be able to perform high quality assurance tests. Further, in such a configuration, by applying a saturation magnetic field of opposite polarity each time the test voltage is applied, it is possible to ensure that the iron core of the EUT in each test is not saturated,
It is possible to prevent an increase in test time such as a retest. In addition, as described above, the method of the present invention saturates the iron core of the voltage adjusting reactor, specifically, the test voltage is applied in a state in which a direct current is applied to the control winding of the voltage adjusting reactor. Even with this method, the current waveform of the reduced voltage and the current waveform of the specified voltage become the same, and it becomes possible to immediately and accurately determine the presence or absence of a failure of the EUT, shorten the test time, and reduce the reliability. It becomes possible to perform quality assurance tests with high quality.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a magnetic state of an iron core of a voltage adjustment reactor for explaining a method of the present invention.

FIG. 2 is a principle diagram of a test circuit performed by interposing a resistor as the method of the present invention.

FIG. 3 is a characteristic diagram showing a magnetic state of an iron core of a voltage adjustment reactor for explaining another method of the present invention.

FIG. 4 is a characteristic diagram showing a magnetic state of an iron core of a voltage adjustment reactor for explaining still another method of the present invention.

FIG. 5 is a test circuit diagram showing an impulse test method according to an embodiment of the present invention.

6A and 6B are voltage / current waveform diagrams by the test circuit of FIG. 5, where FIG. 6A is a waveform diagram when a reduced voltage is applied, and FIG.
And (C) and (D) are waveform diagrams when the specified voltage is applied.

FIG. 7 is a voltage / current waveform diagram by an impulse test method according to a different embodiment of the present invention.
Is a waveform diagram when a reduced voltage is applied, and (B), (C) and (D) are waveform diagrams when a specified voltage is applied.

FIG. 8 is a test circuit diagram showing an impulse test method according to still another embodiment of the present invention.

9 is a test circuit diagram showing a connection state of control windings not shown in the test circuit of FIG.

FIG. 10 is a voltage / current waveform diagram by the test circuit of FIGS. 8 and 9.

FIG. 11 is a test circuit diagram showing an impulse test method according to still another embodiment of the present invention.

FIG. 12 is a voltage / current waveform diagram by the test circuit of FIG. 11.

FIG. 13 is a test circuit diagram of a primary winding side of a conventional reactor built-in type rectifier transformer by an impulse test method.

FIG. 14 is a test circuit diagram on the secondary winding side of the conventional reactor built-in type rectifier transformer by an impulse test method.

FIG. 15 is a test circuit diagram showing the circuits of FIGS. 13 and 14 together.

FIG. 16 is a voltage / current waveform diagram by a conventional impulse test method, (A) is a waveform diagram when a reduced voltage is applied, and (B), (C), and (D) are waveform diagrams when a specified voltage is applied.

FIG. 17 is a principle diagram of a conventional test circuit.

FIG. 18 is a characteristic diagram showing a magnetic state of an iron core of a voltage adjustment reactor according to a conventional test circuit.

[Explanation of symbols]

T, T1, T2: primary winding, t, t1, t2: secondary winding, VCR: voltage adjusting reactor, F: iron core, t0: output terminal, R: resistance, S: current shunt, E: ground, A
1, A2: DC power supply

Claims (8)

[Claims] 1. The primary winding is a winding on the AC side, and
The secondary winding is the winding on the DC side, the output terminal of the secondary winding is connected to the rectifier via the voltage adjustment reactor, and the control winding is wound around the iron core of the voltage adjustment reactor. An impulse test method for a transformer for
In the method in which the secondary winding is grounded via the voltage adjustment reactor, and the impulse test voltage is applied to one end of the primary winding with the other end of the primary winding grounded, the core of the voltage adjustment reactor is An impulse test method for a reactor built-in rectifier transformer, characterized in that a test voltage is applied without being saturated. 2. A reactor built-in rectifier transformer according to claim 1, wherein a test voltage is applied in a state where the secondary winding is grounded via a voltage adjusting reactor and a resistor. Impulse test method. 3. The method according to claim 1, wherein a magnetic field of the iron core of the voltage adjusting reactor is applied with a saturation magnetic field having a polarity opposite to the polarity magnetized by a test voltage, and then the magnetic field of the iron core is once returned to zero. Impulse test method for rectifier transformer with built-in reactor, characterized by applying a test voltage continuously. 4. The impulse test method for a rectifier transformer with a built-in reactor according to claim 3, wherein a saturation magnetic field having an opposite polarity is applied each time a test voltage is applied. 5. The method according to claim 3 or 4,
Impulse of a rectifier transformer with a built-in reactor characterized by applying an opposite polarity saturation magnetic field to the iron core of the voltage adjustment reactor by applying an impulse voltage of opposite polarity to the test voltage polarity to one end of the primary winding. Test method. 6. The method according to claim 3 or 4,
An impulse test method for a rectifier transformer with a built-in reactor, characterized in that a saturation magnetic field of reverse polarity is applied to the iron core of the voltage adjustment reactor by applying a direct current to the control winding of the voltage adjustment reactor. 7. The primary winding is an AC side winding, and
The secondary winding is the winding on the DC side, the output terminal of the secondary winding is connected to the rectifier via the voltage adjustment reactor, and the control winding is wound around the iron core of the voltage adjustment reactor. An impulse test method for a transformer for
An impulse test method for a rectifier transformer with a built-in reactor, characterized in that the test voltage is applied while the iron core of the voltage adjustment reactor is saturated on the side of the same polarity as that magnetized by the test voltage. 8. The impulse test method for a transformer for a rectifier with a built-in reactor according to claim 7, wherein an iron core of the voltage adjusting reactor is saturated by passing a direct current through the control winding.