Self-calibrating a transformer tester requires standard equipment and professional knowledge. It involves following a specific calibration procedure according to the instrument model. Ordinary users are not advised to attempt this themselves. If self-calibration is necessary, please refer to the following general steps:
Confirm if self-calibration is supported. Most professional-grade testers (such as the HDZRC series) are factory-calibrated and explicitly state, "Do not calibrate yourself unless there are special circumstances."
If the instrument provides a "calibration" menu or requires inputting a standard resistance value, limited self-calibration is supported, but a professional standard instrument is still required.
Prepare Standard Calibration Equipment
Self-calibration requires a high-precision standard source; otherwise, it will be invalid:
Standard Voltage/Current Source: Output accuracy one level higher than the instrument being calibrated.
Standard Resistance Box: Accuracy up to 0.01%, such as 10KΩ, 1KΩ, and other mid-range resistors.
Standard Turns Ratio Source: Used for simulating the ratio output of the turns ratio tester.
All standard equipment must be within its valid calibration period.
Common Self-calibration Types and Key Operating Points
DC Resistance Tester Self-calibration
Connect a standard resistor (e.g., 10KΩ, 1KΩ), and calibrate to the seven ranges (20KΩ, 2KΩ, etc.) according to the on-screen prompts.
If the system prompts "The system has detected an incorrect resistor connection," check the wiring or replace the standard resistor.
Turns Ratio Tester Calibration
Use a standard turns ratio signal source as input and compare the instrument reading with the standard value.
Adjust internal parameters to ensure the error is less than the instrument's rated accuracy (e.g., ±0.1%).
Comprehensive parameter calibration (voltage, current, power)
Referring to JJF(New)58-2021 standard, AC voltage (0.1~750)V and current (0.1~100)A are calibrated within the frequency range of 40~70Hz.
Maximum permissible errors: Voltage ±0.05%, Current ±0.2% (clamp-on), Power ±0.5%
