Product Introduction
DC resistance measurement is an indispensable test item for transformers after delivery, overhaul, and tap changer replacement. In general, using traditional methods to measure the DC resistance of transformer windings and large power inductive equipment is a time-
consuming and labor-intensive task. To address this situation, shorten measurement time, and reduce the workload of test personnel, Wuhan UHV has developed the DC Resistance Tester.
The DC Resistance Tester adopts advanced power supply technology and features stable performance, rapid measurement, compact size, ease of use, high measurement accuracy, and good data repeatability. It is an ideal device for measuring the DC resistance of transformer windings and large power inductors.
The DC Resistance Tester complies with the requirements of DL/T 845.3-2004, as well as national standards GB/T 6587-86 General Outline of Environmental Tests for Electronic Measuring Instruments and GB/T 6593-86 Test Rules for the Quality of Electronic Instruments.
Product Characteristics
1. Advanced Power Supply Technology: Utilizes novel power supply technology for DC resistance testing, ensuring stable performance.
2. Rapid Measurement: Enables fast testing to improve work efficiency.
3. Compact and User-Friendly: Small volume and easy to operate.
4. High Precision and Repeatability: Offers high measurement accuracy and excellent data repeatability.
المعايير الفنية
| project | Technical indicators and parameters | note |
| اختبار الحالي | 2.5A，5A，10A，20A，50A | / |
| نطاق القياس | 2.5A：10mΩ～8Ω | / |
| 5A： 1mΩ～4Ω | / | |
| 10A：1mΩ～2Ω | / | |
| 20A：1mΩ～1Ω | / | |
| 50A：1mΩ～500mΩ | / | |
| دقة القياس | ±0.2%(full range) | / |
| data storage | 255 | / |
| عرض | شاشات الكريستال السائل | Resistance is 4 1/2 bits |
| Maximum resolution | 0.1mΩ | / |
| مزود الطاقة | AC 220V±22V，50Hz±2Hz | insurance tube5A |
| Maximum power | 1500W | Testcurrent for 10A |
| work environment | environment temperature：0℃～40℃；Relative humidity ：≤80% | / |
| مقدار | 440x230x490mm3 | / |
| وزن | 16kg | with accessories |
Application Scenarios
1. Factory testing and quality inspection of power transformers
After production is completed for distribution transformers, oil-immersed transformers, dry-type transformers, and large power transformers, DC resistance measurement is performed on high-voltage, low-voltage, and each tap winding to verify winding connection quality, soldering workmanship, and three-phase resistance consistency, ensuring products meet factory technical standards.
2. Substation equipment installation, commissioning, and acceptance
Before commissioning newly built or expanded substations, perform on-site winding DC resistance testing on transformers to check for winding damage, wiring abnormalities, or poor tap changer contact during transportation and installation, providing a reliable basis for safe equipment commissioning.
3. On-load tap-changer (OLTC) condition assessment
For maintenance and overhaul of on-load tap-changers in power transformers, measure winding resistance variations at different tap positions to evaluate switching mechanism and contact condition, promptly identifying potential faults such as increased contact resistance, contact wear, or unstable contact.
4. Power grid preventive testing and condition-based maintenance
During annual grid maintenance, preventive testing, and condition-based maintenance, perform periodic winding DC resistance testing on in-service transformers. By comparing with historical data, determine whether there are issues such as inter-turn short circuits, broken strands, loose connections, or aging in the windings, enabling equipment health condition assessment.
5. Maintenance testing of main and auxiliary transformers in power plants
Applicable for maintenance testing of main transformers, auxiliary transformers, and excitation transformers in thermal, hydro, nuclear, and new energy power plants. High-precision DC resistance measurement verifies winding and lead connection conditions, improving operational reliability of critical power equipment.
6. Maintenance of large electrical equipment in industrial enterprises
Widely used in steel, petrochemical, mining, cement, and rail transit industries for periodic testing of large power transformers, reactors, motor windings, and other equipment, helping maintenance personnel quickly locate winding defects and reducing the risk of unplanned outages.
7. Power equipment repair and major overhaul acceptance
After transformer factory repair, winding rewinding, lead replacement, or major overhaul completion, DC winding resistance testing verifies repair quality and confirms that winding parameters for each phase have returned to normal, providing technical basis for returning the equipment to service.
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FAQs
Q: What is a transformer DC winding resistance tester? Why is it an important device in transformer testing?
A: A transformer DC winding resistance tester is a specialized testing device that calculates winding DC resistance by applying a stable DC current to the windings and measuring the voltage drop. It is primarily used to evaluate the electrical continuity of winding conductors, lead connections, and tap changers. It can help identify issues such as poor contact, broken conductor strands, soldering defects, and three-phase resistance imbalance. It is an important testing tool in transformer factory testing, acceptance inspection, and preventive maintenance.
Q:What types of equipment are suitable for use with the transformer DC winding resistance tester?
A: This equipment is not only suitable for oil-immersed transformers, dry-type transformers, auto-transformers, and distribution transformers, but is also widely used for reactors, generator stator windings, large motors, and other inductive power equipment. For any equipment that requires inspection of winding connection quality, conductor integrity, or tap changer condition, the DC winding resistance tester can be used for testing.
Q: Does temperature variation affect winding resistance test results?
A: Yes. The resistance of both copper and aluminum conductors changes with temperature, so data measured at different ambient temperatures cannot be directly compared. Typically, test results need to be converted to a unified reference temperature in accordance with international or industry standards, in order to facilitate historical trend analysis and condition assessment of the equipment.
Transport、Reservation
If the equipments need to be transported, it is suggested to use the apparatus packing cases of this company and some damping goods, in order not to bring some unwanted damage which may cause you much loss.
Do not stack or pile the equipments if wood cases are not used in the transportation. The utmost stacking layer is two when using the apparatus packing cases of this company. The faceplate of the apparatus should be upward during transportation.
Reservation
The equipment should be laid indoors in a room which is dry, dustless, ventilating and with no corrosive gas. Do not stack or pile the equipment if wood cases are not used in the transportation.
The faceplate of the equipment should be upward when reserving. Put some moisture proof goods under the equipment to prevent the equipment from wetting.
Unpacking and Checking
Make sure the arrow sign of the outer pack is upwards before unpacking. Do not beat forcibly when unpacking in order not to damage the equipment. Unpack the case and take out the equipment, keeping the outer pack and the damping goods, which is not only convenient for your future transportation and reservation but also can protect the environment.
The content of checking
Take out the equipment after unpacking, check and count the equipments and sittings according to the packing list. Please contact with our company if the number is not correct, and we will reply to you as soon as possible.
After-sales service
This product has an overall warranty of one year with three guarantees and a lifelong maintenance, if there is any quality problem of the equipment under warranty, our company will provide free maintenance. If the damage is caused by the improper manipulation or carelessness of the user, we provide preferential services.
We expect that you can give us some valuable advice for our products, so please fill out the “User feedback card” carefully after receiving the equipment and send it to our company in time. We will set up the user record for the equipment you have purchased so as to offer you quicker and better service.
