20A 3-Channel DC resistance tester

Product Introduction

The DC resistance of transformers is a mandatory test item for semi-finished products during manufacturing, factory acceptance tests for finished products, installation, handover tests, and preventive maintenance tests conducted by power utilities. It effectively identifies manufacturing defects such as material selection issues, welding flaws, loose connections, missing strands, and broken wires in transformer windings, as well as potential hazards that may arise during operation. To meet the demand for rapid DC resistance measurement in transformers, our company has developed the MEZRC-WIII(20A) three-channel DC resistance tester specifically for YN-connected windings. This instrument enables simultaneous three-phase energization, independent current and voltage sampling, and concurrent measurement and display of three-phase resistance values and three-phase imbalance rates. It significantly reduces transformer DC resistance testing time, resolving the issue of lengthy DC resistance testing for each tap winding of power transformers. The required time is only one-third of traditional methods.

Product Parameter (specification)

Output Current	Auto-select current (max 20A)
Range	0 to 100Ω
Accuracy	±(0.2% + 2 digits)
Minimum Resolution	0.1μΩ
Operating Temperature	-20 to 40°C
Ambient Humidity	≤80%RH, no condensation
Power Supply	AC220V±10%, 50Hz±1Hz
Dimensions	Length 400mm × Width 340mm × Height 195mm
Net Weight	8kg

Product feature and application

The instrument delivers high output current and features automatic current selection for simplified operation.

Three-channel measurement with real-time data acquisition simultaneously measures three resistance values and calculates three-phase resistance imbalance rate.

Supports both simultaneous three-phase measurement and traditional single-channel measurement, with built-in temperature conversion for user convenience.

Equipped with comprehensive protection circuits for enhanced reliability.

Built-in calendar clock, 500-group data storage, retrieval, and printing capabilities.

Configurable print information including resistance phase sequence and tap position.

Industrial plastic enclosure, lightweight and portable.

Audible discharge alarm with clear discharge indication to minimize operational errors.

Prodection details

Suitable for factory acceptance testing of semi-finished/finished transformers, installation acceptance testing, and preventive maintenance testing by power utilities. Used to detect defects and potential hazards in transformer windings, including material selection, welding, loose connections, strand gaps, and broken wires.

Company Qualifications

FAQ

1)What winding connection configurations are compatible with the MEZRC-WIII (20A) Three-Channel DC Resistance Tester?

Answer: The instrument's three-channel measurement mode is only compatible with YN-type transformer windings. The single-channel measurement mode imposes no specific winding connection restrictions and allows resistance measurement of test specimens using conventional methods.

2)What are the key safety requirements before and after testing with the MEZRC-WIII (20A) Three-Channel DC Resistance Tester?

Answer: Before testing, ensure operators possess basic electrical equipment knowledge. Avoid harsh environments such as rain, high temperatures, or direct sunlight. The instrument must be reliably grounded. After testing, wait until the discharge alarm sound completely stops before turning off the power, removing test leads, or switching the tap position of the no-load tap-changing transformer. Moving test clamps or power supply lines during testing is strictly prohibited.

3)What data storage and output functions does the MEZRC-WIII (20A) Three-Channel DC Resistance Tester offer?

Answer: This instrument features built-in storage for 500 sets of data, supporting data retrieval. It is equipped with a printer capable of printing resistance values, test current, phase sequence, tap position, and other information. A USB interface allows test records to be exported to a USB drive. It also includes an RS485 communication interface for interfacing with a host computer.

Hot Tags: 3-channel dc resistance tester, China 3-channel dc resistance tester manufacturers, factory