50A Three-channel DC Resistance Tester with Magnetization and Demagnetization
Product Description
50A Three-channel DC Resistance Tester with Magnetization and Demagnetization
The GDZC-50S transformer DC resistance tester is mainly used to detect defects in transformer windings, such as poor material selection, incomplete welding, loose connections, and broken strands, thus identifying potential operational hazards.
This machine integrates three core functions: three-phase synchronous testing, magnetizing, and whole-machine demagnetization, significantly reducing the testing time for DC resistance of tap windings in large power transformers. It supports multiple winding testing modes, including YN and D (Y), and features neutral point lead resistance compensation for YN windings. Equipped with a 7-inch color touchscreen and an English operating interface, it also features onboard thermal printing, USB flash drive export, and RS232 host computer communication. The industrial-grade protective portable case makes it suitable for both workshop/laboratory and substation field operations.
◇Three-phase synchronous testing significantly improves on-site testing efficiency.
It supports simultaneous energization of all three phases of YN-connected windings, independent current and voltage sampling, synchronous measurement of three-phase resistance, and automatic calculation of three-phase imbalance rate. It eliminates the need for repeated phase-changing wiring, greatly reducing testing time for multi-tap transformers; it also retains the phase-by-phase testing mode, enabling phase-by-phase testing of YN and D (Y) windings.
◇Automatic Temperature Conversion for Copper-Aluminum Windings
The winding material can be set to copper or aluminum, and the instrument automatically calls the corresponding temperature conversion factor; after entering the measured temperature of the sample, the instrument directly outputs the resistance value converted to the target temperature, making it convenient to generate test reports directly.
◆Magnetizing function, compatible with large five-limb iron-core transformers
Built-in high and low voltage series magnetizing circuit, specifically designed for large five-limb iron-core transformers with low-voltage delta connection; accelerates core magnetic circuit saturation, enabling rapid and accurate measurement of low-voltage winding DC resistance, solving the pain point of excessively long testing time for large-capacity transformers.
◆Built-in demagnetizing module, eliminating residual magnetism in the iron core after testing
DC resistance testing leaves residual magnetism in the transformer core, interfering with subsequent no-load and impedance test results. The instrument has a built-in demagnetizing function, eliminating the need for external demagnetizing equipment; it directly demagnetizes the transformer core after testing, ensuring accurate subsequent test data.
This device can store 100 sets of complete test records with timestamps.
It has a built-in thermal printer for on-site printing of paper reports.
USB interface: Export test data to a USB flash drive.
RS232 serial port: Connect to a computer for remote control and data upload.
It has a built-in hardware calendar clock to record the actual test time for each test.
GDZC-50S tester uses the Kelvin four-wire method to output a constant DC current to the transformer windings, independently acquiring current and voltage signals to calculate the winding DC resistance.
For YN star-connected transformers, it supports three-phase synchronous excitation, acquiring the A0/B0/C0 three-phase resistances in one go and automatically calculating the three-phase imbalance rate. For large transformers with five-limb core delta windings, it activates auxiliary excitation to accelerate magnetic circuit saturation and shorten the stabilization waiting time.
After testing, the instrument automatically discharges the inductive windings with audible and visual alarms. The built-in demagnetizing module can be invoked to output a decaying reverse current to eliminate residual magnetism in the transformer core. All test results can be saved locally, printed on-site, or uploaded to a computer via USB flash drive or RS232 for test archiving.
Test wiring classification on the two-winding transformer
1) Output current: | Three-phase test: 25A+25A;10A+10A; 5A+5A; 1A+1A;200mA+200mA; 20mA+20mA; Single-phase test: 50A;20A; 10A; 5A; 1A; 200mA;20mA; |
2) Measurement range: | Three-phase test:25A+25A: 0.4mΩ～0.1Ω; 10A+10A: 1mΩ～0.6Ω; 5A+5A: 2mΩ～1.2Ω; 1A+1A: 10mΩ～6Ω; 200mA+200mA: 100mΩ～30Ω； 20mA+20mA: 10Ω～200Ω； Single-phase test: 50A: 0.2mΩ～0.2Ω; 20A: 0.5mΩ～1Ω; 10A: 1mΩ～2Ω; 5A: 2mΩ～4Ω; 1A: 10mΩ～20Ω; 200mA: 100mΩ～100Ω; 20mA: 10Ω～20KΩ |
3) Accuracy: | ±0.2% |
4) Minimum resolution: | 0.1μ |
| 5) Operating temperature: | -10～40 |
| 6) Ambient humidity: | ≤80%RH |
| 7) Power supply | AC220V±10%, 50Hz±1Hz |
Transformer Manufacturers: Factory Acceptance Testing of Power Transformers
Power Grid Substations: New Transformer Commissioning, Overhaul, Tap Changer Replacement, Preventive Maintenance Testing
Wind Power and Solar Power Step-up Substations: Transformer Winding Inspection
On-site Inspection by Third-Party Power Testing Service Agencies
Inspection of Transformer Winding Welding Defects, Loose Joints, Broken Strands, and Poor Tap Changer Contact Faults
Demagnetization Treatment of Cores After DC Resistance Testing of Large-Capacity Transformers
Q1: Can this instrument test both star (YN) and delta (D(Y)) transformer windings?
A: Yes. It supports synchronous three-phase testing and phase-by-phase testing of YN windings; it also supports testing of D(Y) delta windings. For large five-limb core transformers, an auxiliary excitation function can be activated.
Q2: Does it support temperature conversion between copper and aluminum windings?
A: Yes. The winding material (copper/aluminum) can be selected on the touchscreen. The actual sample temperature is input, and the instrument automatically outputs the converted resistance value.
Q3: How do I export and archive the test report?
A: Three methods: direct thermal printing on-site; export via USB flash drive; data upload via RS232 serial port connection to a host computer software. The instrument can internally store up to 100 records.
Q4: What is the purpose of the demagnetization function?
A: After DC resistance testing, residual magnetism remains in the core, causing distortion in subsequent no-load loss and other test data. The built-in demagnetization module directly eliminates residual magnetism in the transformer core without additional equipment.
Contact us
Contact person: Christine
Email: gold05@hy-industry.com
Whatsapp/Wechat/Mobile: +86 15123029885