CN205941713U - Low output capacity current mutual inductance transformation ratio testing device - Google Patents

Abstract

The utility model discloses a small output capacity current mutual inductance transformation ratio test device, which includes a housing, which includes: a millivolt level voltmeter (Us), an AC digital voltmeter (Up), and an input voltage source ( AC), wherein the millivolt voltmeter (Us) leads to the first terminal and the second terminal; the AC digital voltmeter (Up) leads to the third terminal and the fourth terminal; the AC digital voltmeter The third terminal and the fourth terminal of (Up) are connected to an input voltage source (AC); a display area is provided on the housing for displaying the transformation ratio value obtained through testing and calculation. The utility model has the advantages of convenient operation, low cost, high measurement accuracy, light weight, etc., and is especially suitable for performing variable ratio testing of current transformers with small output capacity on site.

Description

A small output capacity current mutual inductance transformation ratio test device

technical field

The utility model relates to a current transformer transformation ratio test device, in particular to a small output capacity current transformer transformation ratio test device.

Background technique

At present, the field current transformer transformation ratio test adopts the current method to test, as shown in Fig. 1 , which shows an existing current transformer transformation ratio test. In this test method,

The specific test method is as follows: connect the current source AC at both ends of the primary side of the current transformer (L1, L2), use the ammeter ip to test the current Ip of the primary coil N1, and connect the ammeter at both ends of the secondary side of the current transformer (s1, s2) is, test the ratio of the primary current to the secondary current of the secondary coil N2 current Is, that is, the ratio of Ip/Is, which is the transformation ratio of the current transformer.

The symbols in the figure are explained as follows:

N1 is the primary winding of the current transformer.

N2 is the secondary winding of the current transformer.

L1 is the polarity end of the primary winding of the current transformer.

L2 is the non-polar end of the primary winding of the current transformer.

s1 is the polarity end of the secondary winding of the current transformer.

s2 is the non-polar end of the secondary winding of the current transformer.

* indicates the polarity of the primary and secondary windings of the current transformer.

AC is a current source.

ip is the primary winding ammeter connected to the current transformer.

is is the ammeter connected to the secondary winding of the current transformer.

Ip is the current of the primary winding of the current transformer.

Is is the current of the secondary winding of the current transformer.

The current method to measure the transformation ratio of a current transformer is simple and convenient in field application, but it has the following disadvantages: if the current transformer has a small output capacity, the secondary side current of the current transformer is too small, which may easily lead to inaccurate conversion of the transformation ratio.

Utility model content

The technical problem to be solved by the utility model is to provide a small output capacity current mutual inductance ratio test device, which can improve the accuracy of the small output capacity current mutual inductance ratio test.

In order to solve the above technical problems, the embodiment of the utility model provides a small output capacity current mutual inductance transformation ratio test device, including a housing, which includes: a millivolt level voltmeter Us, an AC digital voltmeter (Up), and connected to an input voltage source where:

The millivolt voltmeter Us leads to a first terminal and a second terminal, wherein the first terminal is electrically connected to one end (L1) of the primary side coil of the current transformer, and the second terminal is connected to the current transformer. The other end (L2) of the primary side coil is electrically connected;

The AC digital voltmeter (Up) leads to the third terminal and the fourth terminal, wherein the third terminal is electrically connected to one end (s1) of the secondary side coil of the current transformer, and the fourth terminal is connected to the current transformer’s The other end (s2) of the secondary side coil is connected;

The third terminal and the fourth terminal of the AC digital voltmeter (Up) are connected to an input voltage source;

Further, a display area is provided on the housing for displaying the transformation ratio value obtained through testing and calculation.

Among them, further include:

AC voltage regulator T, its voltage regulating terminal is connected to the third terminal of the AC digital voltmeter, and its negative pole is connected to the fourth terminal of the AC digital voltmeter; the input voltage source is connected to the AC between the positive and negative terminals of the voltage regulator.

Wherein, an adjusting part of the AC voltage regulator is arranged on the housing.

Implementing the utility model has the following beneficial effects:

The utility model has the advantages of convenient operation, low cost, high measurement accuracy, light weight, etc., and is especially suitable for performing variable ratio testing of current transformers with small output capacity on site.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

Fig. 1 is the schematic diagram of the transformation ratio test of current transformer in the prior art;

Fig. 2 is the wiring diagram of the first embodiment of a small output capacity current mutual inductance transformation ratio testing device provided by the utility model;

Figure 3 is a schematic diagram of the interface of the small and medium output capacity current mutual inductance ratio test device in Figure 2;

Fig. 4 is the application schematic diagram of the small output capacity current mutual inductance transformation ratio test device in Fig. 2;

Fig. 5 is a wiring schematic diagram of the first embodiment of a small output capacity current mutual inductance transformation ratio test device provided by the utility model;

Fig. 6 Fig. 5 is a schematic diagram of the interface of the small output capacity current mutual inductance transformation ratio test device;

FIG. 7 is an application schematic diagram of the small output capacity current mutual inductance transformation ratio test device in FIG. 5 .

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in Fig. 2 and Fig. 4, a first embodiment of a small output capacity current mutual inductance transformation ratio testing device provided by the present invention is shown. In this embodiment, the small output capacity current mutual inductance transformation ratio test device includes a housing, which includes: a millivolt level voltmeter Us, an AC digital voltmeter Up, and an input voltage source AC connected to it.

The millivolt voltmeter Us leads to a first terminal and a second terminal, wherein the first terminal is used for electrical connection with one end L1 of the primary side coil of the current transformer, and the second terminal is used for connecting with the current transformer. The other end L2 of the primary side coil of the device is electrically connected;

The AC digital voltmeter Up leads to a third terminal and a fourth terminal, wherein the third terminal is used to electrically connect with one end s1 of the secondary side coil of the current transformer, and the fourth terminal is used to connect with the current transformer. The other end s2 of the secondary side coil is connected;

The third terminal and the fourth terminal of the AC digital voltmeter Up are connected to an input voltage source;

Further, a display area is provided on the housing for displaying the transformation ratio value obtained through testing and calculation.

It can be understood that the housing further includes:

The signal acquisition device is used to separately acquire the voltage value U1 of the primary side N1 of the current transformer tested by the millivolt voltmeter, and the voltage value of the secondary side N2 of the current transformer tested by the AC digital voltmeter U2 voltage value;

The transformation ratio calculation unit is used to calculate the transformation ratio value N of the current transformer according to the voltage value U2 and the voltage U1, wherein N=U2/U1, and the transformation ratio is displayed on the display area. For example, in an example, take a current transformer with a transformation ratio of 400/5 as an example: when a voltage of 40V is applied to the secondary side of the current transformer, the measured primary side voltage of the current transformer is 500mV. By comparing the secondary side voltage of the anti-current transformer with the primary side voltage value, the transformation ratio K=40/0.5=80 is calculated, which is 400/5.

Wherein, the signal acquisition device and the transformation ratio calculation unit can be realized by means of hardware or software.

In practical applications, the millivolt level voltmeter Us may be, for example, a 200 millivolt voltmeter, and the AC digital voltmeter may be, for example, a 300V AC digital voltmeter, and the above is just an example.

As shown in Figure 5 and Figure 7, a second embodiment of a small output capacity current mutual inductance transformation ratio test device provided by the present invention is shown, which is the same as that in the aforementioned Figures 2 to 4 The difference of the illustrated first embodiment is that it further comprises:

AC voltage regulator T, its voltage regulating terminal is connected to the third terminal of the AC digital voltmeter, and its negative pole is connected to the fourth terminal of the AC digital voltmeter; the input voltage source is connected to the AC between the positive and negative terminals of the voltage regulator.

In addition, the adjustment part of the AC voltage regulator is provided on the housing, as shown in the figure marked T.

For more details, you can refer to the foregoing description of the first embodiment, which will not be repeated here.

Correspondingly, the utility model comprises the following steps when in use:

Electrically connect the first terminal drawn from the millivolt voltmeter Us to one end L1 of the primary side coil of the current transformer, and connect the second terminal drawn from the millivolt voltmeter Us to the primary coil of the current transformer. The other end L2 of the side coil is electrically connected;

The third terminal drawn from the AC digital voltmeter Up is electrically connected to one end s1 of the secondary side coil of the current transformer, and the fourth terminal drawn from the AC digital voltmeter Up is connected to the secondary side coil of the current transformer. The other end s2 of the side coil is connected;

Respectively collect the voltage value U1 of the primary side N1 of the current transformer tested by the millivolt voltmeter, and the voltage value U2 of the secondary side N2 of the current transformer tested by the AC digital voltmeter;

According to the voltage value U2 and voltage U1, calculate the transformation ratio N of the current transformer, where N=U2/U1;

Display the transformation ratio value on the display area.

It can be understood that the utility model has the following beneficial effects:

The utility model has the advantages of convenient operation, low cost, high measurement accuracy, light weight, etc., and is especially suitable for performing variable ratio testing of current transformers with small output capacity on site.

What is disclosed above is only a preferred embodiment of the utility model, and of course it cannot limit the scope of rights of the utility model. Therefore, the equivalent changes made according to the claims of the utility model are still covered by the utility model. scope.

Claims (3)

1. a kind of little output capacity Current Mutual Inductance transformation ratio test device, including housing, includes in housing：Millivolt level voltmeter （Us）, AC digital voltmeter（Up）, and it is connected with input voltage source（AC）It is characterised in that wherein：

Described millivolt level voltmeter（Us）Draw the first terminals and the second terminals, described first terminals and current transformer First siding ring one end（L1）The other end of the first siding ring of electrical connection, the second terminals and current transformer（L2）Electricity Connect；

AC digital voltmeter（Up）Draw the 3rd terminals and the 4th terminals, described 3rd terminals and current transformer One end of second siding ring（s1）The other end of the second siding ring of electrical connection, the 4th terminals and current transformer（s2）Phase Connect；

Described AC digital voltmeter（Up）The 3rd terminals and the 4th terminals be connected with input voltage source（AC）；

Further, it is provided with viewing area on the housing, by test and calculate obtained change ratio for display.

2. a kind of little output capacity Current Mutual Inductance transformation ratio test device according to claim 1 is it is characterised in that further Including：

Alternating voltage pressure regulator（T）, its voltage adjusting end is connected to the 3rd terminals of described AC digital voltmeter, and its negative pole connects 4th terminals of described AC digital voltmeter；Described input voltage source be connected to described alternating voltage pressure regulator positive pole and Between negative pole.

3. a kind of little output capacity Current Mutual Inductance transformation ratio test device according to claim 2 is it is characterised in that described The adjustment portion of described alternating voltage pressure regulator is provided with housing.