20A DC Resistance Tester

Product Introduction

Designed for measuring the DC resistance of inductive coils like transformers, the MEZRC-W20A DC Resistance Tester is used in factory, installation, handover, and preventive testing. It includes 6 current selection levels and has a measurement range from 100μΩ to 100KΩ, providing high precision and robust anti-interference capabilities. With support for interfaces in both Chinese and English, it facilitates data storage, exportation, and real-time printing. The device is user-friendly, offers extensive protective features, is portable, and built to last.

Product Parameter (specification)

1. Output Current	Testing across six ranges at 20A, 10A, 5A, 2A, 100mA, and <5mA.
2. Measurement Range	From 100μΩ to 1Ω (20A) 500μΩ bis 2Ω (10A) 1 mΩ bis 4 Ω (5 A) 5 mΩ to 10 Ω (2 A) 100 mΩ bis 200 Ω (100 mA) 200 Ω bis 100 kΩ (<5 mA)
3. Precision	0.2% ± 2 μΩ
4. Resolution	0.1 micro-ohm
5. Temperature during operation	0°C to 40°C
6. Ambient Humidity	At most 90% RH, without condensation
7. Höhe	maximal 1000 m
8. Energieversorgung	AC220V±10 %, 50 Hz±1 Hz
9. Maße	400 mm × 340 mm × 195 mm
10. Gewicht	8,6 kg

Product feature and application

1. With six output current settings that range from a maximum of 20A to a minimum of <5mA, the instrument is suitable for measuring DC resistance across a broader range of transformers and instrument transformers.
2. The device offers a wide measurement range (from 100μΩ to 100KΩ).
3. The quicker response time permits the direct switching of on-load tap changers during measurement, accompanied by automatic data refresh.
4. The device has an audible discharge alarm and clear discharge indication, which minimizes operational mistakes.
5. Comprehensive protection functions reliably safeguard the instrument from back-EMF impacts, thereby ensuring greater reliability.

6. The interface, featuring a 7-inch color LCD screen, presents information in a clear and visually appealing manner, with the ability to output real-time prints.
7. The device has operating interfaces in both Chinese and English, which can be configured based on customer specifications.
8. Furnished with an RS485 communication interface for the transfer of test data to backend systems.
9. With a capacity for up to 500 test records, the storage is ample.
10. The USB interface allows for the transfer of data to external storage devices.
11. Enhanced parameter settings facilitate the configuration of transformer test windings, tap positions, test phases, specimen temperature, and equivalent temperature.
12. The design of the industrial plastic enclosure guarantees that it can be carried easily and that it will have a long service life.

Prodection details

Transformer-Related Testing:

Covers factory acceptance tests for semi-finished and finished transformers during manufacturing, installation and handover tests, post-overhaul inspections, and checks after tap changer adjustments. Also includes preventive tests for power utilities to identify issues such as winding joint weld quality, interturn short circuits, tap changer contact and position mismatches, lead wire breaks, and strand breaks in multi-strand conductors. Applicable to main and distribution transformers rated 110kV and below.

Other Inductive Equipment Testing:

Suitable for factory, installation, handover, and preventive tests on inductive coils such as instrument transformers, reactors, and electromagnetic operating mechanisms. Detects manufacturing defects and operational hazards including material selection issues, welding flaws, loose connections, strand shortages, and broken wires. Also measures DC resistance of inductive test specimens like motors.

Low-resistance equipment measurement:

Extended application for DC resistance measurement of low-resistance electrical equipment like cables. Suitable for indoor and outdoor scenarios (requires avoidance of harsh environments such as rain exposure and corrosive gases).

Company Qualifications

FAQ

1)What data storage and transmission methods does the MEZRC-W20A DC Resistance Tester support?

Answer:
This instrument offers multiple data storage and transmission functions, specifically:
Internal Storage: Equipped with a large-capacity storage module, it can store up to 500 test records. Press the "Save" button on the panel after testing to store current data.
USB Export: Using the instrument's USB port, insert a USB drive and select "Record Export" in the "Record Query" menu to transfer stored data to the USB drive;
Background Transmission: Equipped with an RS485 communication interface, test data can be transmitted in real-time to a host computer or backend system. Configure the baud rate (default 1200) and communication address (range 1~247);
Real-time Printing: An internal micro printer allows direct printing of test results by pressing the "Print" key on the panel after testing.

2)How to save and export test records after testing?

Answer:
Save Records: Press the "Save" key on the instrument panel after testing to store the current record internally. The instrument can store up to 500 test records.
Exporting Records: ① On the main screen, move the cursor to the "Record Query" menu and press the confirmation key to enter; ② Insert a USB drive (a USB icon will appear in the lower right corner of the LCD); ③ Use the direction keys to move the cursor to the "Record Export" option, press the confirmation key, and the stored test data will be exported to the USB drive.

3) What are the key safety requirements when using this instrument to measure no-load tap-changing transformers?

Answer:
Before switching tap positions, wait until the discharge indicator alarm sound completely stops and confirm discharge has ended before proceeding;
When disconnecting test leads after testing, wait for the discharge alarm to stop before turning off the power and removing the test leads;
During testing, do not move the test clamps or disconnect the power supply;
When selecting the test current, refer to the range specified in the technical specifications to avoid over-range or under-range operation, which may cause unstable test results.

Hot Tags: 20a dc resistance tester, China 20a dc resistance tester manufacturers, factory