CN201440375U

CN201440375U - Mutual inductor

Info

Publication number: CN201440375U
Application number: CN2009200055140U
Authority: CN
Inventors: 小岛广稔
Original assignee: Nissin Electric Co Ltd
Current assignee: Nisshin (Wuxi) electromechanical Co., Ltd.; Nissin Electric Co Ltd
Priority date: 2009-02-27
Filing date: 2009-02-27
Publication date: 2010-04-21
Anticipated expiration: 2019-02-27

Abstract

The utility model provides a mutual inductor with small size and low cost. A closed magnetic circuit iron core (21) and a primary coil (L1) are coated by an epoxide resin casting mold layer, wherein the primary coil (L1) is wound on the iron core, a secondary coil (L2) is wound on the iron core (21) coated by the epoxide resin mold layer, and the secondary coil (L2) can be wound to any turn number in accordance with the requirements.

Description

Instrument transformer

Technical field

The utility model be for the ratio error of measuring voltage instrument transformer with in phase error is limited to permissible range and the error adjustment that is connected at the secondary side of measuring voltage instrument transformer with the relevant content of auxiliary transformer.

Background technology

Reduce error in order to improve precision, secondary side at the measuring voltage instrument transformer connects auxiliary transformer, be connected with the secondary side load again,, ratio error and phase error be limited in the range of allowable error by selecting to be arranged on the different tap of auxiliary transformer secondary side.

Fig. 5 measures with voltage transformer and the example of the error adjustment that is attached thereto with auxiliary transformer.In Fig. 5,1 refers to the measurement voltage transformer (VT) that has twined primary winding W1 and secondary coil W21 and adjust coil W22 on iron core 101.2 refer to the auxiliary transformer that has twined primary winding L1 and secondary coil L2 and constitute on closed magnetic circuit iron core 201, and Zb is the secondary side load.

The secondary coil L2 of auxiliary transformer have a plurality of can coarse adjustment and the tap coil L2a-L2c of fine setting.And from tap coil L2a, L2b, the two ends of L2c lead to respectively tap (ta1, ta2), (tb1, tb2), (tc1, tc2).

The primary winding L1 of auxiliary transformer is connected on the two ends of the adjustment coil W22 of measuring voltage instrument transformer 1, the end of secondary coil W21 is connected with an end of one of them tap coil of the secondary coil of auxiliary transformer, then then secondary load between the other end of the other end of secondary coil W21 and the tap coil that links to each other with W21 one end.

Fig. 6 is the circle of uncertainty line chart example of measuring voltage instrument transformer 1, and the longitudinal axis is represented the phase error theta of measuring voltage instrument transformer, and transverse axis is represented ratio error ε, and the interior survey part of rectangle frame A is represented range of allowable error as shown in Figure 6.The straight line a that dots among Fig. 6 represents is the error characteristics of (do not connect auxiliary transformer, only connect secondary load Zb at the two ends of secondary coil W21) measuring voltage instrument transformer before the error adjustment.What the straight line b that represents with solid line among Fig. 6 represented is to insert auxiliary transformer 2 as shown in Figure 5, and the tap that the secondary of suitable selection auxiliary transformer is surveyed carries out the adjusted error characteristics of error.In this example, shown in straight line a, ratio error had surpassed permissible range before error was adjusted.By the error adjustment, shown in straight line b, ratio error only has been adjusted Δ ε, just the limits of error has been fixed in the range of allowable error.

Fig. 7 is the another kind of situation example of measuring with the circle of uncertainty line chart of voltage transformer 1.Error characteristics before Fig. 7 cathetus a represents to adjust, straight line b represents the adjusted error characteristics of error, in this example, ratio error and phase error have all surpassed range of allowable error before adjusting, but by the error adjustment, phase error and ratio error only have been adjusted Δ θ and Δ ε respectively, and error is fallen in the range of allowable error.

Error adjustment in the past is wrapped in primary winding L1 and secondary coil L2 on the annular closed magnetic loop iron core 201 with transformer as shown in Figure 8, formation transformer body 2 ' and, it is positioned in the casing 3.In casing, 3 inject the urethane synthetic resin then, with transformer body 2 ' cast encapsulated moulding.Be installed on the terminal board 4 above the casing 3, be respectively arranged with the terminal that links to each other with primary winding L1 two ends, and the tap terminal of drawing from several tap coils of formation secondary coil.

The utility model content

The technical problem that solves

The error characteristics of voltage transformer change according to the deviation of core characteristics, and the error adjustment must have the function that the error of voltage transformer can be limited in the range of allowable error with transformer.

Error adjustment is in the past all poured into a mould encapsulated moulding with urethane resin with primary winding, secondary coil and the iron core of auxiliary transformer, causes the number of turns of secondary coil to change.

Therefore, for the size of the ratio error that can not be subjected to voltage transformer and phase error influences and carries out error and adjust, just need secondary coil to constitute by a plurality of tap coils of the tap coil that contains tap coil that coarse adjustment uses and microcall.

And because auxiliary transformer is poured into a mould encapsulated moulding by urethane synthetic resin, so the notes type is just essential with casing 3, this has just caused the part number of auxiliary transformer to increase, and transformer maximizes, and cost also can uprise.

Particularly in terminal box that 3 usefulness auxiliary transformers are packed into, it is very big that the auxiliary transformer of each phase becomes, and then casing also can become very big, like this, auxiliary transformer is installed just need account for very big space.

And, auxiliary transformer in the past irrespectively carries out the error adjustment in order to realize with the size of error in default error range, be provided with the tap coil of a lot of coarse adjustment and microcall at secondary side, do not use, caused waste thereby after the error adjustment of reality, have a lot of coils.

Technical scheme

The utility model is wrapped in primary winding on the closed magnetic circuit iron core, primary winding and iron core are encapsulated by epoxy resin injection molding layer, epoxy resin injection molding layer is partly made the structure of through hole at the closed magnetic circuit iron core, and secondary coil twines the coil that need the number of turns to iron core by through hole on epoxy resin injection molding layer.

Beneficial effect

The utility model with primary winding and iron core encapsulation, has saved the structure of casing with epoxy resin, and auxiliary transformer is oversimplified.

Simultaneously, because for once coil and iron core epoxy resin casting are easy to batch process, also reduced manufacturing cost.

And, can twine the secondary coil of the corresponding number of turns according to the error characteristics of instrument transformer owing to be that only as required the number of turns is twined secondary coil on the epoxy resin injection molding, unwanted coil can not be provided with after the error adjustment.

Furtherly, because the coil of redundance need not be set, not need to be provided with casing and make structure become simple, the auxiliary transformer miniaturization that just can become simplifies the structure, and improves the batch process property, has reduced cost.

Description of drawings

Fig. 1 is relevant with the new case of this practicality, the oblique view of a form of implementation outward appearance of expression auxiliary transformer.

Fig. 2 is the in-built sectional drawing of the identical auxiliary transformer of expression.

Fig. 3 is that the auxiliary transformer that will have 3 phases of structure shown in Figure 1 is installed in the oblique Visual figure of state on the terminal board.

Fig. 4 is the newly auxiliary transformer in the case and the loop diagram of voltage transformer connection status of this practicality of expression.

Fig. 5 is a loop diagram of representing the connection status of auxiliary transformer in the past and voltage transformer.

Fig. 6 is a kind of circle of uncertainty line chart of situation of the error characteristics of expression voltage transformer.

Fig. 7 is the circle of uncertainty line chart of another kind of situation of the error characteristics of expression voltage transformer.

Fig. 8 is the oblique view that the auxiliary transformer before the expression constitutes.

Embodiment

Fig. 1 is the outward appearance oblique view, and Fig. 2 is a sectional drawing.21 is that to twine the ring-type magnetic circuit that silicon strip forms iron core-closed in Fig. 2.L1 is the primary winding that is wrapped on the iron core 21.The epoxy resin injection molding 22 that is provided with through hole 22a at iron core 21 places is with iron core 21 and primary winding L1 encapsulation.Epoxy resin layer 22 possesses the enough intensity that is used for encapsulating fully.

22 one-tenth horseshoe-shaped section configurations of epoxy resin injection molding in diagram, it is 22b that there is a flat portions its side, giving prominence to a prism-shaped ledge on the end of the flat 22b direction parallel with tabular surface is 22c, a

terminal gold utensil

23,24 that links to each other with primary winding L1 two ends, be embedded among the flat 22c, there is one section outwards to give prominence to respectively,

metalwork

23,24 has screw hole, and the metal terminal that outside wiring connects can be fixed on metal terminal by these screw holes.

By shown in Figure 1, auxiliary transformer 20 of the present utility model is made of iron core 21, primary winding L1 and secondary coil L2.It is packed that iron core 21 has passed through the through hole 22a of epoxy resin injection molding layer 22, and secondary coil L2 is twining magnetic circuit iron core-closed 20 from epoxy resin injection molding layer 22.Secondary coil L2 is only twining and the ratio error and the phase error of voltage transformer can be limited to the needed number of turns of range of allowable error.

Auxiliary transformer 20 in the new case of this practicality utilize flush type gold utensil 25 be fixed (not diagram) install.Then as shown in Figure 4, primary winding L1 is connected on and adjusts on the coil W22, and the end of secondary coil L2 is connected with the end of the secondary coil W21 of voltage transformer 1, follows secondary load Zb between the other end of the other end of secondary coil W21 and L2.

Make above-mentioned this spline structure, every phase auxiliary transformer smaller volume when the three-phase auxiliary transformer is put into common terminal box, also can make the terminal box miniaturization.And as shown in Figure 3, the auxiliary transformer 20U-20W of 3 phases just can be installed on simple terminal board mounting panel 30.Terminal board mounting panel 30 shown in Figure 3, rectangular mounting panel body 30a is fixed on (not diagram) on the installing rack by screw etc., and terminal board 31 is installed on the front end face of mounting panel main body 30a.According to like this auxiliary transformer of three-phase being installed on the terminal board mounting panel, the configuration of the auxiliary transformer of three-phase has just obtained miniaturization.

Claims

1. an instrument transformer has primary winding and secondary coil, and secondary coil is connected the secondary side of measuring with voltage transformer, and primary winding is wrapped on the closed magnetic circuit iron core and closed magnetic circuit is encapsulated in the epoxy resin pattern together;

It is characterized in that epoxy resin pattern makes the perforation pass at iron core hole place, secondary coil just can be entangled on the epoxy model by through hole like this, and winding needs the coil of the number of turns on iron core, the formation instrument transformer.