JPS60103606A - Autotransformer - Google Patents

Abstract

PURPOSE:To obtain an autotransformer having a small amount of load loss and high efficiency by providing a main winding having a rough tap at its intermediate part and a tap winding having a plurality of fine taps including taps from which a total voltage in the main winding is outputted when one terminal of the main winding is selectively connected with the rough tap and the terminal is selected. CONSTITUTION:A rough tap 34 is provided on a main winding 31, and a selector is provided, which selects a terminal G connected with the rough tap 34 or a terminal F connected with one primary terminal U and connects the selected terminal G or F with the rated fine tap I at which an adjusted secondary voltage becomes equal to a primary voltage, that is, the a'th rated fine tap I counted from the most upper fine tap H. A subsidiary tap 36 at which a voltage lower than the secondary lowest voltage in the case of selecting the terminal F of the selector 35 by the voltage across adjacent fine taps is provided on the main winding 31 and its terminal K is built in a switch 33 together with the fine tap T, thereby allowing the selector 35 to be switched with no current. The rough tap 34 is so selected as the voltage at the most upper tap H becomes lower than that at the terminal K by the voltage across adjacent fine taps.

Description

[Detailed Description of the Invention] [Technical field to which the invention pertains] This invention relates to an autotransformer used as a power source for a furnace or rectifier transformer that requires a wide range of voltage adjustment, and in particular,
The present invention relates to an autotransformer that supplies nine regulated voltage steps approximately twice the number of taps within a predetermined voltage range above and below the primary voltage as the secondary voltage.

[Prior art and its problems]

FIG. 1 is a wiring diagram of a conventional autotransformer of this kind, and this transformer has a main winding 1 energized by a primary voltage,
Connected to the tap P of the main winding a1, it has a plurality of n close taps T wound generally on the same core as the main winding 1, and has a close tap open winding 11i outside the taps C and E at both ends! A total of n+1 close tap-to-tap windings 2& including 2a are provided. There is also a selector 3, one end of which is connected to the coarse tap P, and the other end of which selects either the start or end of the tap winding 2, A or H, and one end of which is connected to the secondary terminal U, and the other end is connected to the fine tap T or the coarse tap. A switch 4 connected to one of the taps P is provided. At that time, a voltage equal to the upper limit voltage (loo 10 m)% is obtained at the upper limit close tap C, a voltage of 100% of the rated close tap DK is obtained, and when P of the selector 3 and a person are connected, the lower limit close tap E
A voltage of (100-b)% of the lower limit voltage is obtained.

For ease of understanding, the explanation may be repeated using specific numbers. The voltage between terminals U and V of gold main winding 1 is 100
%, the voltage obtained on the secondary side is 105-85%, i.e. a = 5%, b = 15%, and n = of the close tap winding.
10. The voltage of the close tap-to-tap winding 2a is 1ch, and the voltage of P is 95%.

When P and B are connected as shown, the voltage at the upper limit tap C is P (95%) + 10X1% = 105q6, the voltage at the rated close tap D is P (95 cm) + 5 X 1 cm = 100%, and at the lower limit tap E The voltage is P(95%)+1%=96%. If U is connected to P, the voltage will be 95q6. P
If and A are connected, the upper limit tap C is P (95%) - 1%
=94chi, similarly, the voltage decreases by 1% for each tap, and the voltage at tap E becomes 85%.

In this case, it is desirable for a door transformer, which uses the tap voltage only during the unstable period when it begins to melt, and uses the voltage of 100 inches for a stable long period of time, to have the least load loss around 100 inches. . However, in conventional wiring, 1
When the voltage is 00, a primary current of 11 flows between U and P of main winding 1, and a primary current of 11 and a secondary current of I2 flow between P and P.
The difference in current is applied to the 20th half of the dense tap winding, and a current of 2 flows between 4B and D, causing a load loss. Further, the close tap winding 2 requires (n+t), ie, 11 close tap windings 2a, making the winding large.

In order to simply eliminate load loss when the secondary voltage is 100% voltage, one primary terminal U is connected to the switch 4 as shown in Figure 2.
Just incorporate it. However, it is good if the adjustment range of the secondary voltage, that is, the adjustment voltages a and b that are added or subtracted from the primary voltage, are equal, but if they are different, for example, a=5%, b=1 as mentioned above.
In the case of 5%, the tap winding 21 must be adjusted to the wider tap range of the adjustment range.
And there is a drawback that the switching device becomes a poor cine economy. For example, if the adjustment range is 105 to 85 inches, tap winding 2
1, the one shown in FIG. 1 requires only 11 close tap opening g 2 a, but the one shown in FIG. 2 requires 16.

[Purpose of the invention]

In addition to the above-mentioned drawbacks of the conventional technology, this invention has the advantage that the load loss is the least when the secondary voltage used most often is equal to the primary voltage, that is, around 100 cm, and the tap winding is small, making it economical. The purpose is to provide an autotransformer.

[Key points of the invention]

In order to achieve the above object, in this invention, an autotransformer has a main winding having a coarse tap in the middle, one end of this main winding and the coarse tap are selectively connected, and the former is selected. It consists of a tap winding having a plurality of close taps, including a tap that outputs the full voltage of the main winding when

[Embodiments of the invention]

FIG. 3 is a diagram showing an embodiment of the present invention, and the same reference numerals indicate those having the same functions as those described above. This autotransformer has a main winding 31 energized by a primary voltage, a plurality of n close taps T and (n
-1) tap winding 32 having inter-tap windings 2a;
It has two windings. In addition, a switching device 33 is provided that sequentially switches the close taps T of the tap winding 32 and connects them to one secondary terminal U, and connects this secondary terminal U to the other primary terminal ■.
A secondary voltage is supplied between the secondary terminal and the other secondary terminal storage connected to. This secondary voltage is (100+
lL)% is the upper limit, too-b)% is the lower limit, and a'
It has a total of n (10 in the figure) dense taps, i.e., n and b'. a' and b' do not necessarily have to be equal.

The main winding 31 is provided with 34 rough taps, and the secondary voltage adjusted by selecting the terminal G connected to the rough tap 34 or the terminal F connected to one of the primary terminals U is 1. Equal to the next voltage □Rated close tap■ That is,
A selector 35 is provided which connects the upper limit density tap H to the a'-th rated density tap ■. In addition, an auxiliary tap 36 is provided on the main winding 31 with a voltage lower by one close tap voltage than the secondary minimum voltage (the voltage of the lower limit close tap J in the figure) when the selector 35 selects the terminal F. By incorporating the selector 35 into the switch 33 together with the close tap T, the selector 35 can be switched without current.

The coarse tap 34 may be selected so that when the selector 35 selects the terminal G, the voltage at the upper fine tap H is lower than the voltage at the terminal by one fine tap inter-tap voltage.

In order to make the above structure easier to understand, the explanation will be repeated using specific numbers. The voltage between terminals U and V of the main winding 31 is 100, and the voltage obtained on the secondary side is 105 to 85.
%, that is, a = 5%, b - 15 chips, n = I G of the close tap winding 32, and the voltage of the close tap inter-tap seaming 2a is 1%, then a' - 5, b' = 4.

As shown in the figure, when the tap is connected to one terminal U of the main winding 31 and connected to 9F, the upper limit tap H is 1
00chi + 5 x 1chi = 105%, 100chi in tap I,
At the lower limit tap J, the voltage is 100q6-4X1ch=96%. As mentioned above, connect the auxiliary tap K to the 9th part of the main winding 31.
Derived from section 5. If the switch 33 is moved to tap K, the selector 35 can connect I and coarse tap G without current. When I and G are connected, the upper limit tap H needs to be 1 inch lower than 95% of the voltage at the auxiliary tap, so it becomes 94t16, and the coarse tap 34 (G) is an additional 5%.
It is sufficient to derive it from a low part, that is, 89% of the main winding 31. In this state, the voltage at the rated close tap I is 89%, and the voltage at the lower limit tap J is 85%.

With this configuration, it is possible to obtain secondary voltages approximately twice (2 times + 1) the number of taps of the tap winding 32 that are continuous in a stepped manner. Further, by using the auxiliary tap 36, there is an advantage that the tap winding 32 can be made smaller by two close tap-to-tap windings 2a than a conventional tap winding under the same conditions.

Note that although the above description has been made using a single-phase device, the present invention can also be applied to a three-phase device as it is. In that case, the other terminal ■ becomes the neutral point.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, in an autotransformer, if the primary voltage and secondary voltage, which are most often used, are the same ioo% voltage, the load current does not flow through the windings, so there is a load loss. Moreover, since there are few winding portions through which load current flows even in other nearby taps, it is possible to obtain a highly efficient autotransformer with low load loss.

[Brief explanation of drawings]

1 and 2 are wiring diagrams of a conventional autotransformer, and FIG. 3 is a wiring diagram of an embodiment of the present invention.

Claims (1)

[Claims] 1) A main winding having a coarse tap in the middle, one end of this main winding and the coarse tap being selectively connected, and when the former is selected, the total voltage of the main winding and a tap winding having a plurality of close taps, including a tap that outputs. 2. In the device described in claim 1, the close tap is provided at the tap that outputs the voltage of the main winding, and outputs a voltage that is one close tap-to-tap voltage lower than the voltage of the lower limit tap at that time. An autotransformer characterized by having an auxiliary tap on the main winding.