I understand your concern. From a professional perspective, determining the quality of a transformer tester's material hinges on a systematic comparison of the nominal material specifications with actual performance and industry standards. The cold-rolled silicon steel sheets, amorphous alloys, copper windings, and stainless steel casing you mentioned are the four key dimensions for evaluating the quality of its core components.
Core Material: Cold-rolled Silicon Steel Sheets vs. Amorphous Alloys The core is the "magnetic heart" of the tester, and its material directly affects measurement accuracy and stability.
Cold-rolled Silicon Steel Sheets: The standard for quality is the use of high-permeability, low-iron-loss oriented cold-rolled silicon steel sheets (such as 30Q130 and 35Q140). Verification can be performed in the following ways:
Check if the product technical documentation specifies the silicon steel sheet grade and iron loss value (P1.7/50 ≤ 1.3W/kg is preferred).
Use a B-H curve tester to measure the hysteresis loop and determine if the permeability and saturation magnetic induction intensity meet the standards.
In actual operation, the no-load current should be stable, with no significant temperature rise or abnormal noise.
Amorphous Alloy:
If an amorphous alloy core is claimed to be used, the qualification standards include:
The core has a wound structure (not laminated), with a strip thickness of approximately 0.03mm.
The no-load loss should be at least 70% lower than that of a silicon steel sheet core of the same capacity.
Note its sensitivity to mechanical stress; avoid impacts and deformation during transportation and installation.
Winding Material: Copper windings are the preferred choice for high performance.
The winding material determines the conductivity and temperature rise control.
Copper winding qualification standards:
Resistivity should be ≤1.724×10⁻⁸ Ω·m (20℃), verifiable through DC resistance testing.
Non-destructive testing should be performed using a transformer material analyzer (e.g., ZX-BC188), with the program automatically identifying and outputting the "copper" attribute.
High-end equipment should use oxygen-free copper wires with a smooth, oxidation-free surface and strong solder joints.
Beware of "aluminum instead of copper": The resistivity of aluminum windings is approximately 1.6 times that of copper, easily leading to measurement errors and overheating. On-site identification can be performed using the thermoelectric effect method or the temperature coefficient of resistance method.
