The HZ-5100S provides four output current levels, each corresponding to a different measurement range. Different gears are not randomly selected. Choosing the right gear may result in higher measurement accuracy and more reliable results. Choosing the wrong gear may cause range exceeding or data distortion.

Range corresponding to four gears

100A range: 0-2000 µ Ω (i.e. 0-2m Ω)

80A range: 0-5m Ω

50A range: 0-10m Ω

30A range: 0-20m Ω

The larger the current, the smaller the range, and the higher the accuracy; The smaller the current, the larger the range, making it suitable for circuits with higher resistance values to be tested.

How to choose the current gear

Preferred 100A gear: This is clearly stipulated by industry standards. The national standard GB/T 11022 and the regulations for the power industry both require that the current for conducting circuit resistance testing of high-voltage switchgear should not be less than 100A. The reason is that high current can effectively penetrate the oxide film on the contact surface and restore the true contact state; The low value measured by the small current may mask the actual problem. Therefore, for any formal inspection that meets the standards, the 100A level should be selected.

When the range exceeds the limit, downshift: If the resistance of the tested circuit exceeds 2m Ω (such as old contacts with severe poor contact or oxidation, or some wiring terminals with high resistance), and the 100A range is not enough, it can be reduced to 80A (range 5m Ω) or 50A (range 10m Ω) to continue measuring. After finding a suitable range, decide whether maintenance is needed.

Applicable scenarios for 30A level: Used when the resistance of the tested circuit is above 10m Ω and below 20m Ω, mainly for certain special test samples or preliminary screening, and not used as the formal inspection current for high-voltage circuit breakers.

What should I do if the current cannot reach the set value

If the wiring is poorly connected or the resistance of the tested circuit exceeds the corresponding gear range, the actual current output by the instrument may not reach the set value. At this point, the instrument will automatically stop and sound an alarm. Solution: First check and re tighten the wiring, confirm and retest; If the resistance does exceed the range, switch to a low gear and re measure.

The 100A test can last up to 60 seconds, meeting the vast majority of on-site verification requirements.