Transformer Demagnetizer 5A 1A 200mA 5mA Automatic Degaussing for Plant Power Transformer Cores| XHXC105

After DC resistance measurement, turns ratio tests or other DC tests, residual magnetism remains in the transformer core because of the inherent hysteresis of ferromagnetic materials. If the transformer is re-energized with residual flux in the core, half-cycle saturation produces a large inrush current rich in harmonics — increasing reactive consumption, risking protective relay misoperation, and even causing sympathetic inrush tripping of neighboring transformers. The XHXC105 transformer demagnetizer removes core residual magnetism before energization using the patented DC variable-frequency attenuation principle, protecting the transformer and the surrounding power network.

• Patented DC variable-frequency attenuation principle for effective core demagnetization
• Three-phase transformers only need B-phase demagnetization (terminals B and 0)
• Automatic mode runs the 5A-1A-200mA-5mA sequence without operator intervention
• Manual mode with selectable current levels for flexible field use
• Automatic current stabilization judgment with 16-bit AD data acquisition
• Fast demagnetization: a manual cycle takes about 3 minutes instead of the former 30-minute process
• Demagnetization effectiveness above 90% per cycle (previously about 80%)
• Directly reuses the current test leads of DC resistance testers for convenient matching
• Two-key operation: red key for selection/reset, green key for confirm/start
• Compact 5kg design that is easy to carry to field sites
• Automatic discharge when the process reaches 100%, with reset key for emergency stop

Leaving residual magnetism in a transformer core before switching back on can trigger a chain of problems for the plant power system:

• Protective relay misoperation that makes transformer energization fail repeatedly
• Inrush current that can damage the transformer and circuit breakers through excessive electrodynamic force
• Sympathetic inrush that trips neighboring transformers and causes large-area outages
• DC components in the inrush that over-magnetize current transformer cores and degrade metering accuracy and relay performance
• Harmonic pollution and voltage sags or swells that disturb other electrical equipment

With the XHXC105, plant teams remove more than 90% of the residual magnetism in a single cycle — about 3 minutes in manual mode or a fully automatic 9-minute sequence — and the instrument discharges automatically when the process reaches 100%.