JPS61269079A - Temperature rise test for transformer - Google Patents

Abstract

PURPOSE:To enable the temperature rise test of a transformer to be simply and accurately performed by short-circuiting a secondary winding in series and supplying a required current from a voltage to a primary winding side. CONSTITUTION:Star-connected secondary windings 2a and 2b are connected to each other in series through three short bars 3. Therefore, when a voltage is applied to a primary winding 1, current with the same strength flows in the secondary windings 2a and 2b through the short bars 3. That is, Ia=Ib. Thus, by connecting a plurality of secondary windings in series, an operation to be conducted in a test can be simplified and performed with a good accuracy without the necessity of using an impedance adjusting load.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for testing a temperature rise in a transformer.

[Conventional technology]

The short circuit method is used for temperature rise tests in transformer assembly plants. That is, the two windings of the transformer are short-circuited and a current corresponding to the total transformer loss (iron loss + copper loss) is supplied to the primary winding. The winding is 2a (Y
When there are 2b (Δ connection) and 2b (Δ connection), each secondary winding is short-circuited with the shorting piece 3 to supply a current that causes total loss from the primary winding 1 (Δ connection) side. U, V, W are primary winding 1
The U-phase, ■-phase, and W-phase input terminals of the secondary winding 2a are shown respectively, and the U-phase, ■-phase, and W-phase output terminals of the secondary winding 2a are Ul, vl,
In Wl, the output terminals of the U phase, ■ phase, and W phase of the secondary winding 2b are indicated by U2, V2, and W2.

However, the primary winding 1 and the secondary winding 2a, the primary winding 1
If there is a difference in impedance between and the secondary winding 2b, each 2
The short circuit currents 1a and rb flowing through the next winding have different values,
Excessive current flows through the secondary winding on the lower impedance side, making the temperature rise test unreliable.

[Problem that the invention seeks to solve]

For this reason, conventionally, the secondary windings 2a and 2b
4. By inserting an appropriate load and adjusting the load, the short-circuit current of each secondary winding 2a, 2b is made to be the same.
1°, when the rectifier transformer supplies power to the rectifiers 4a and 4b, and the secondary winding through which a large current flows, the load becomes a large capacity load, so impedance adjustment is necessary. The problem was that it was very troublesome.

This invention was made to solve the above problem.
The purpose of the present invention is to obtain a temperature rise test method for a transformer that can be easily and accurately performed.

[Means to solve the problem]

In order to achieve the above object, the present invention short-circuits the secondary windings in series to supply the required current from the voltage to the primary side.

[Effect]

In this invention, since the secondary windings are sequentially connected in series, the current flowing through each secondary winding has the same magnitude even without inserting an impedance adjustment load into the secondary winding.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention,
The connected secondary windings 2a and 2b are connected in series by three shorting pieces 3.

Therefore, when voltage is applied to the primary winding 1, the shorting piece 3
A current of the same magnitude flows through each of the secondary windings 2a and 2b. That is, Ia=Ib.

In the above embodiment, a transformer having two secondary windings has been described, but even if the transformer has three or more secondary windings, they may be connected in series in sequence. The type of connection of the secondary winding does not matter.

〔Effect of the invention〕

As explained above, this invention connects a plurality of secondary windings in series when performing a temperature rise test using the short circuit method, so there is no need to use an impedance adjustment load, and the work to be performed during the temperature rise test is reduced. This method is simpler than the conventional method and allows for highly accurate testing.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of a transformer circuit to which this invention is applied, and FIG.
The figure is a circuit diagram showing a conventional test method. In the figure, 1-= primary winding, 2 a, 2 b-
Secondary winding, 3 - shorting piece. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] When a temperature rise test of a transformer having a plurality of secondary windings having the same rating is carried out by the short circuit method, the plurality of secondary windings are successively short-circuited in series. Temperature rise test method.