JPH0739212Y2 - Autotransformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an autotransformer for voltage transformation.

[Prior Art] An autotransformer is used, for example, when it is connected to the input side of a main transformer to transform an output voltage. In this case, the connection between the autotransformer and the main transformer is as shown in Fig. 3 in the case of a single-phase circuit.

That is, the autotransformer 1 is arranged on the input side of the main transformer 2, and the winding 3 of the autotransformer 1 is provided with, for example, four voltage taps t1 to t4. These voltage taps t1
~ T4 is the input side winding 5 of the main transformer 2 via the switching mechanism 4.
Connected to. Here, the movable terminal 6 of the switching mechanism 4 is configured to be connected to any of the taps t1 to t4 by switching.

[Problems to be solved by the invention] Now, assume that the input voltage is Vi, and the output voltage of the autotransformer 1 at this time is Vt1 at tap t1, Vt2 at tap t2, Vt3 at tap t3, and Vt4 at tap t4. . Here, at tap t1, V
t1 = Vi, that is, the input voltage Vi becomes the voltage of the tap t1 of the autotransformer 1 as it is, and this serves as the input power source of the main transformer 2.

Then, in the autotransformer configured as shown in FIG. 3, when the tap t1 is used, the input voltage to the main transformer 2 is increased.
When applying Vi, as shown in the figure, autotransformer 1
The winding 3 is connected and the input voltage Vi is applied, whereby the iron core is excited and loss occurs. This loss is a no-load loss of the autotransformer 1, and always occurs as a constant loss regardless of the magnitude of the load. Moreover, since the tap t1 is normally a rated tap and is frequently used, the autotransformer continuously generates no-load loss during operation.

Therefore, in order to eliminate the no-load loss of the autotransformer and obtain a highly efficient transformer, switching mechanisms 7 and 4 are provided on the input side and the output side of the autotransformer 1, respectively, as shown in FIG. May be configured. This is to provide a plurality of voltage taps t2 to t4 for voltage transformation on the winding 3 of the autotransformer 1, while providing the terminal 9 of the rated tap T1 not connected to the winding 3 to move the switching mechanism 4. Terminal 6 has these taps T1, t2
To t4 are selectively switched, and the movable terminal 11 of the input side switching mechanism 7 is connected to the winding 3 of the autotransformer 1 and the terminal 8 is connected.
And the terminal 10 connected to the tap T1 is selectively switched.

According to this configuration, if the movable terminal 11 of the switching mechanism 7 is switched to the terminal 10 and the movable terminal 6 of the switching mechanism 4 is switched to the terminal 9 of the rated tap T1, the winding 3 of the autotransformer 1 is input. Since the input voltage Vi is directly applied to the input side of the main transformer 2 without being applied to the autotransformer 1, no unloaded loss occurs in the autotransformer 1.

However, in the case of the configuration shown in FIG. 4, two expensive switching mechanisms 4 and 7 are required, and the switching work becomes complicated, and the movable terminal 11 of the switching mechanism 7 is changed when switching to the taps t2 to t4. There was a risk of erroneous operation, such as leaving the terminal in the terminal 8.

An object of the present invention is to obtain an autotransformer that is highly efficient, small-sized, and lightweight by eliminating the no-load loss of the autotransformer with one switching mechanism.

[Means for Solving Problems] In the autotransformer according to the present invention, a series winding and a shunt winding, which are wound around the same iron core, are connected in series via a connection point, and Connect the end opposite to the connection point to the power supply side, connect the connection point to the load side, and connect the end opposite to the connection point of the shunt winding to the power supply side and the load side. In the autotransformer, the first shunt winding portion located on the side of the connection point and the second portion located on the side opposite to the connection point by providing a separating portion in the winding of the shunt winding. Configure the shunt winding part,
A first voltage tap is provided at the winding end located on the separation side of the first shunt winding part, and a second voltage tap is provided at the winding end located on the separation side of the second shunt winding part. A voltage tap and a third voltage tap are provided at the connection point and a rated tap is provided at an end of the series winding on the side opposite to the connection point, and when voltage transformation is performed, the first voltage tap and the second voltage tap are provided. A tap is selected, or a second voltage tap and a third voltage tap are selected, and a movable terminal is connected to select and connect the third voltage tap and the rated tap when the voltage transformation is not performed. It is characterized in that a switching mechanism is provided.

[Operation] As a result, when a rated tap is used with one switching mechanism, the series winding is short-circuited and the input voltage is directly applied to the load side to de-energize the iron core, and when voltage transformation is performed, the shunt winding is used. It can be connected, transformed to a predetermined voltage, and applied without a load.

[Embodiment] The embodiment of the present invention shown in FIG. 1 will be described below. The series winding 22 and the shunt winding 23 wound on the same iron core are at the connection point b.
Are connected in series via. The end portion a of the series winding 22 located on the opposite side of the connection point b is connected to the power source side and provided with a rating tap T1, and the connection point b is the input side of the load side main transformer 2. A voltage tap t2 (third voltage tap) is provided while being connected to one end of the winding 5. An end e located on the opposite side of the connection point b of the shunt winding 23
Is the input side winding 5 of the main transformer 2, which is the power supply side and the load side.
Respectively connected to the other end of. Further, in this shunt winding 23, a separating portion 23a is provided in the winding and a first shunt winding portion located on the side of the connection point b and a second shunt winding located on the side opposite to the connection point b. A shunt winding portion is constructed. A voltage tap t4 (second voltage tap) is provided at the winding end located on the side of the separating portion 23a of the first shunt winding portion.
However, a voltage tap t3 (first voltage tap) is provided at each winding end located on the side of the separation portion 23a of the second shunt winding portion. The voltage taps t2 to t4 and the rating tap T1 are incorporated in the switching mechanism 14, and the movable terminal 16 of the switching mechanism 14 selects and connects two of these taps T1, t2 to t4.

In this case, the movable terminal 16 has a voltage tap t2 at the connection point b and a voltage tap t3 at the winding end portion of the second shunt winding portion or the winding of the second shunt winding portion when performing voltage transformation. When the voltage tap t3 at the end portion and the voltage tap t4 at the winding end portion of the first shunt winding portion are selected and connected so as to straddle the separating portion 23a of the shunt winding 23, and when voltage transformation is not performed, The rated tap T1 and the voltage tap t2 at the connection point b are selected and connected in a state where the separation portion 23a is opened.

Assuming that the autotransformer according to the present invention is connected to the input side winding 5 of the main transformer 2 and the input voltage Vi is applied, the movable terminal 16 of the switching mechanism 14 causes the rated tap T1 of the series winding 22 and the voltage. If the tap t2 is selected and connected, the series winding 22 is short-circuited and the input voltage Vi is directly applied to the input side of the main transformer 2. At this time, in the autotransformer 21, the series winding 22 has the switching mechanism 14
Is short-circuited and the shunt winding 23 is not connected by the separating portion 23a, the core is not excited by any winding. Further, at the time of voltage transformation, if the voltage tap t2 and the voltage tap t3 or the voltage tap t3 and the voltage tap t4 are selected and connected by the movable terminal 16 of the switching mechanism 14 so as to straddle the separation portion 23a of the shunt winding 23. , Vt2,3, V
The t3,4 voltage can be obtained. Therefore, it is possible to obtain exactly the same effect as the case of eliminating the no-load loss at the time of the rated tap of the autotransformer with only one switching mechanism by using two switching mechanisms in the related art. Further, since all taps can be switched by one switching mechanism, it is possible to solve the problem of erroneous operation which is a concern when the conventional switching mechanism is two. Further autotransformer 21
In many cases, the main transformer 2 and the main transformer 2 are housed in the same tank and cooled by common insulating oil. In this case, however, the total size of the switching mechanism is about half, and the tank size can be reduced. The amount of expensive insulating oil used can be reduced. Further, for example, when the main transformer 2 is a transformer for a rectifier or a furnace, the tap switching mechanism is often driven by an electric operating device and its operation is controlled from a remote place. By applying the invention, it is possible to obtain the effect that only one electric operation device is required and the configuration of the remote control device is simplified.

Although FIG. 1 shows a single-phase connection, it can be similarly applied to a three-phase connection. The embodiment shown in FIG. 2 is an embodiment in which an autotransformer is connected in a star shape. In this case, a switching mechanism 14 is provided to each of the series winding 22 and the shunt winding 23 of the autotransformer of each phase. Will be provided.

[Effects of the Invention] As described above, according to the autotransformer of the present invention, the input voltage can be applied by the single switching mechanism without causing loss to the autotransformer when the voltage transformation is not performed. In addition, since voltage taps can be selected and transformed to an arbitrary voltage during voltage transformation, high efficiency, downsizing and weight reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of the autotransformer according to the present invention, FIG. 2 is a connection diagram showing another embodiment of the autotransformer of the present invention, and FIGS. 3 and 4 are respectively. It is a wiring diagram which shows the conventional autotransformer. 1,21 …… Single transformer, 2 …… Main transformer, 4,7,14 …… Switching mechanism, 6,11,16 …… Movable terminal, 22 …… Series winding, 23 ……
Shunt winding, 23a …… Separating part, T1 …… Rating tap, t2 to t4
...... Voltage tap.

Claims (1)

[Scope of utility model registration request] 1. A series winding and a shunt winding, which are wound on the same iron core, are connected in series via a connection point, and an end of the series winding opposite to the connection point is connected to a power supply side. In the autotransformer that is connected, the connection point is connected to the load side, and the ends of the shunt winding on the side opposite to the connection point are connected to the power supply side and the load side. A separating portion is provided in the winding to form a first shunt winding portion located on the connection point side and a second shunt winding portion located on the opposite side to the connection point.
A first voltage tap at the winding end located on the separation side of the shunt winding part, and a second voltage tap at the winding end located on the separation side of the second shunt winding part, And a third at the connection point
Voltage tap and a rated tap at the end of the series winding opposite to the connection point, and when voltage transformation is performed, the first voltage tap and the second voltage tap are selected, or the second voltage tap is selected. The voltage tap and the third voltage tap are selected, and a switching mechanism having a movable terminal for selecting and connecting the third voltage tap and the rating tap when the voltage transformation is not performed is provided. Winding transformer.