20A DC Resistance Tester

Product Introduction

The MEZRC-W20A DC Resistance Tester is used in production, installation, handover, and preventive testing to measure the DC resistance of inductive coils, such as transformers. With a measurement range of 100μΩ to 100KΩ and six current selection levels, it offers strong anti-interference capabilities and excellent precision. It makes data storage, exportation, and real-time printing easier with support for interfaces in both Chinese and English. The gadget has several protective characteristics, is easy to use, portable, and long-lasting.

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. The device can measure DC resistance over a wider range of transformers and instrument transformers thanks to its six output current settings, which range from a maximum of 20A to a minimum of <5mA.
2. A broad measurement range (from 100μΩ to 100KΩ) is provided by the gadget.
3. Direct switching of on-load tap changers during measurement, along with automatic data refresh, is made possible by the faster response time.
4. The gadget reduces operating errors with its visible discharge indication and audible discharge alarm.
5. All-encompassing protection features consistently defend the device from back-EMF effects, guaranteeing increased dependability.

6. The interface, which has a 7-inch color LCD screen, can produce real-time prints and displays information in an understandable and aesthetically pleasing way.
7. The gadget can be adjusted according to client needs and provides operating interfaces in both Chinese and English.
8. Equipped with an RS485 connection link so that test data can be sent to backend systems.
9. The storage is sufficient, holding up to 500 test records.
10. Data can be transferred to external storage devices using the USB port.
11. Improved parameter settings make it easier to configure the specimen temperature, equivalent temperature, test phases, tap locations, and transformer test windings.

12. The industrial plastic enclosure's design ensures its long service life and ease of transportation.

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.

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