1Transformer DC resistance testerexplanation

The measurement of JY44 DC resistance is a necessary item for semi-finished and finished product factory testing, installation, handover testing, and preventive testing of inductive coils such as transformers, transformers, reactors, and electromagnetic operating mechanisms. It can effectively detect manufacturing defects such as material selection, welding, loose connection parts, missing strands, and broken wires of inductive coils, as well as hidden dangers after operation. In order to meet the needs of rapid measurement of DC resistance in inductive coils, our company has developed a DC resistance tester using our own technological advantages. This instrument adopts a new power technology, which has the characteristics of small size, light weight, large output current, wide range, and digital display. The whole machine is controlled by a microcontroller, which automatically completes self checking, data processing, display and other functions, and has automatic discharge and discharge indication functions. The instrument has high testing accuracy, easy operation, and can achieve rapid measurement of direct resistance.

2、 Safety measures for transformer DC resistance bridge

1Before using this instrument, be sure to read this manual carefully;

2This instrument can be used both indoors and outdoors, but should be avoided from places such as rain, corrosive gases, etc.Instruments should avoid severe vibrations;

3The maintenance, care, and adjustment of instruments should be carried out by professionals;

4After the test is completed, be sure to wait for the discharge alarm sound to stop before turning off the power and removing the test line;

5When measuring an unloaded voltage regulating transformer, be sure to wait for the discharge indicator alarm sound to stop before switching gears;

6During the testing process, it is prohibited to move the test clip or turn off the power supply line.

IIITransformer 44 DC resistance bridgePerformance Characteristics

1. The instrument has a high output current and is lightweight;

2. The instrument provides 6 output current options, with a maximum output of 10A current;

3. Instrument measurementResistance temperature conversion can be performed according to the set temperature;

4. Equipped with a comprehensive protection circuit, the performance is more reliable;

5. Powered by lithium-ion batteries, convenient for on-site operation;

6. Equipped with sound discharge alarm to reduce misoperation;

7. 4.3-inch color LCD display with a resolution of 480 × 272TFTTrue color display screen, Chinese operation menu;

8. The instrument adopts a machine wire integrated mode, with built-in testing wires for easy portability;

9. The local storage capacity is large, and it can store up to 200 test records;

10. Equipped with a USB interface, it can transfer test data to a USB drive;

11. The parameter settings are more complete, allowing for the setting of the transformer's test winding, tap position, test phase, test sample temperature, converted temperature value, etc.

4Transformer DC resistance measuring bridgetechnical indicators

1. Output current: 10A, 5A, 1A, 200mA, 40mA, ＜ 5mA;

2. Range:

0.001Ω-0.1Ω （10A）

0.03Ω-1Ω （5A）

0.06Ω-5Ω （1A）

0.1Ω-50Ω （200mA）

0.3Ω-200Ω (40mA)

100Ω-100kΩ (<5mA)

3. Accuracy: 0.2%± 2 μ Ohm;

4. Resolution: 0.1 μ Ω;

5. Working temperature: -20~40℃；

6. Environmental humidity:≤80%RH， No condensation;

7. Altitude:≤ 1000 meters;

8. Working power supply: 12V/6Ah lithium battery power supply;

9. External dimensions:323*275*135mm；

10. Weight: 5.0kg (including testing line).

5JY44 DC resistance measuring bridgeSystem Introduction

The instrument panel is shown in Figure 1

Figure 1

1、U+、U-：Voltage output and input terminals, red is positive and black is negative;

2、I+、I-：Current output and input terminals, red is positive and black is negative;

3. LCD:4.3-inch color LCD display,Display menu, current and resistance values, etc;

4. Charging interface:The charging port for the built-in battery of the DC instrument can only be used with the accompanying charger;

5. Power switch:Instrument power control switch.

6. USB port:Instrument andUSB interface;

7. Grounding post:For the grounding of the entire machine casing, it is a protective ground;

8Return key:After the measurement is completed or the parameter settings are finished, press this key to return to the previous menu;

9Confirm key:In the main menu, the cursor is on any menu, press this key to enter the corresponding sub menu; Select the submenu for direct resistance testing with the cursor, and press this key to enter the direct resistance testing state; On the direct resistance test interface, after the test data is stable, press this key to save the current data;

10、Right cycle directional keys, eachRight loop movement of the cursor between the main menu and the corresponding functional options;

11Left circular directional key,The left circular movement of the cursor between the main menus and their corresponding functional options;

12The up loop directional key allows for upward scrolling of various main menus and functional options;

13The down loop directional keys enable downward scrolling of various main menus and functional options.

6、 II. Testing and Operation Method of JY44 DC Resistance Measuring Bridge

（1） Test wiring

ASingle phase measurement method, as shown in the following figure

Figure 2

BThe auxiliary magnetic method wiring is shown in Figure 3-5 (applicable toY_（N）-d-11Connection group).

Figure 3

Figure 4

Figure 5

When measuring the low voltage side of large capacity transformers, the high current of the DC resistance tester is relatively small, or in order to speed up the measurement speed, it is possible to chooseMagnetic assisted measurement.In the above figure,Figures 3, 4, and 5 respectively show the measurement of low voltageRacTheRbaTheRcbThe wiring method.

（二）、操作方法

• Turn on the power switch of the instrument and enter the main interface when turned on, as shown in the following figure:

Figure 6

press/ The key can scroll the cursor in a loop between various main menus.

Test current selection:Move the cursor toDirect resistance testMain menu, then press/The key can cycle to select the test current.When choosingautomaticDuring testing, the instrument will automatically select the appropriate output current for testing based on the resistance value of the test sample.

• After selecting the current, pressconfirmStart testing with the key. LCD (Liquid Crystal Display)“ChargingAs shown in the following figure:

Figure 7

During the process of waiting for the test current to stabilize, various parameters of the transformer can be set. press/The key cursor is onwinding、part、tap、Test sample temperatureandconversion temperatureLoop selection between parameters, when the cursor selects a parameter, press/ Key to modify the parameter value.

After the test current value stabilizes, the instrument automatically calculates and displays the test resistance value at the current temperature of the sample, and also displays the converted resistance value at the converted temperature, as shown in the following figure.

Figure 8

• After completion, pressreturnPress the key to disconnect the instrument output power and discharge at the same time. The LCD display interface will show a discharge prompt, sound an alarm, and the LCD will return to the direct resistance test interface state. As shown in the following figure:

Figure 9

If any abnormal situations occur during the testing process, please pressresetPress the key, and the LCD will quickly return to the initial startup interface.

Attention: When testing on load tap changers or other inductive loads, please be sure to wait until the discharge alarm sound ends before rewiring for the next measurement, or turn off the power and remove the test line!

4On the startup main menu interface (Figure 6), move the selection cursor toRecord InquiryMenu, pressconfirmPress the key to display the saved record data, as shown in the following figure:

Figure 10

press/The key cursor is onDelete record、Delete all、Record exportLoop between selections.

Delete record:Move the cursor to the delete record option and pressconfirmKey, delete the current single record;

Delete all:Move the cursor to the delete all option and pressconfirmThe key can delete all the data stored on this machine at once;

Record export:Move the cursor to the record export option and plug in the instrumentUDisk (appears in the bottom right corner of the LCD display)UDisk icon), pressconfirmThe key can export the currently stored data toUInside the plate.

Operation completed, pressreturnKey to exit the record query submenu.

5On the startup main menu interface (Figure 6), move the selection cursor totime correctionMenu, pressconfirmThe key,Enter the time modification submenu, as shown in the following figure:

Figure 11

inTime SettingsPress on the interface/Move the cursor with the key, select the position to be modified, and press/Press the key to modify the value of that position. After time correction is complete, pressreturnKey exit time setting returns to the main interface.

7、 Precautions

1. Before measuring the reverse tap connection of an unloaded voltage regulating transformer, it is necessary to wait for the discharge to end and the alarm sound to stop before switching the tap points.

2. Before disconnecting, be sure to wait until the discharge is complete, the alarm stops, and the power is turned off before proceeding with the disconnection.

3. When selecting the current, refer to the range in the technical specifications column and do not use it beyond or below the range. When using beyond the range, due to the current not reaching the preset value, even if the test is forcibly continued, the stability of the results is too poor. When the range is insufficient, the current is too small, resulting in unstable data for large capacity transformers. When these two states occur, confirm the range and select the appropriate range for testing.

4. Charging instructions: To charge the instrument, the built-in charger must be used. When charging, the red light of the charger will light up, indicating that the battery is fully charged, and the indicator light of the charger will change from red to green.