I. Overview

In transformer manufacturing semi-finished products, finished products factory test, installation, overhaul, change of tap changer, handover test and preventive test requirements of the power department, the DC resistance of the transformer or the transformation ratio of the transformer should be measured. It can check the welding quality of the winding joints and whether there is an inter-turn short circuit in the winding. It can detect whether the contact of each position of the voltage tap changer is good and whether the actual position of the tap changer is consistent with the indicated position. Whether there is a stock break, etc. The traditional test requires multiple wiring interval tests of two instruments, which takes a long time and poor efficiency, which seriously affects the production progress.

In order to meet the needs of fast measurement of DC resistance and transformation ratio of transformers, XX direct resistance transformation ratio integrated tester developed by our company. The instrument adopts one-time wiring, which can complete the transformation ratio test and the test of high and low six-phase DC resistance without disconnecting the wires, and the above functions can be realized only through the touch screen operation.

II. Main technical indicators

1. Main indicators of direct resistance:

DC resistance test current: AUTO, <20mA, 40mA, 200mA, 1A, 3A, 10A

DC resistance test range and accuracy: 10A: 0.5mΩ～800mΩ ±(0.2%+2 digits)

3A: 2mΩ～2Ω ±(0.2%+2 words)

1A: 5mΩ～10Ω ±(0.2%+2 digits)

200mA: 100mΩ～50Ω ±(0.2%+2 words)

40mA: 500mΩ～250Ω ±(0.2%+2 words)

<20mA: 50Ω～50KΩ ±(0.5%+2 words)

Minimum resolution: 0.1μΩ

Display: liquid crystal display, resistance display effective figures are 4 digits

Data storage: 1000 groups

Working environment: Relative humidity: <80%RH, no condensation Ambient temperature: -20℃～40℃

Power supply: AC 220V±10V, 50Hz±1 Hz fuse 5A

Maximum power consumption: 200W

2. Main indicators of transformation ratio:

1. Test range: Transformation ratio -- 0.9～10000 Angle -- 0-360°

2. Ratio accuracy: ±0.1%+2 words (0.9-500)

±0.2%+2 words ( 501-2000 )

    ±0.5%+2 words ( 2001-10000 )

3. Angle accuracy: ±0.2°

4. Output voltage: automatically adjusted according to the load

5. Resolution: ratio -- minimum 0.0001, angle -- 0.01°

6. Working power supply: AC220V±10% 50±1Hz

7. Ambient temperature: -10℃～40℃

8. Relative humidity: ≤85%, no condensation

III. Features

Features of direct resistance

1. This product is suitable for 10KV and 35KV level distribution transformers, transformers, motors, generators and other inductive load tests, as well as the measurement of wires, relay switch contacts, etc.

2. With temperature conversion function, it can be converted to resistance values at different temperatures according to customer needs, which is convenient for data comparison.

5. It has protection functions such as discharge sound alarm, power supply overheating, and voltage reverse connection.

7. The on-load switch can be switched directly in the measurement state, and the instrument automatically refreshes the data without reset operation.

9. It has 6 current gears, and has automatic current gear, which can automatically select the current gear according to the load.

Ratio features

1. The three-phase precision inverter power supply is used inside the instrument, which eliminates the harmonic influence of the mains voltage during measurement and makes the measurement more accurate. When the working power source is a generator, there will be no impact.

2. Three-phase output voltage is used to improve the test speed. It can measure the angle between phases and automatically identify the wiring group 0-11. For the rectifier transformer with multiple windings measured at low voltage, the transformation ratio and 7.5 can be measured without disconnecting the low voltage side. ° Angle deviation.

3. It is suitable for a wide variety of transformers, especially suitable for the measurement of Z-type transformers, rectifier transformers, grounding transformers, and electric furnace transformers.

4. It has high and low voltage reverse connection protection, transformer turn-to-turn short circuit protection, tap changer not in place protection, output full short circuit protection, and increases the stability of the instrument.

5. After inputting the rated parameters, it can automatically measure the transformer ratio, error value and tap position of the tap changer. Especially for the tap changer with asymmetrical tap change, it can also accurately measure the exact position of the transformer tap changer. A tap changer that can measure 99 tap points.

6. Seven-inch high-brightness touch color LCD, clear display under strong light, full touch screen operation, free switching between Chinese and English.