A common problem in design and selection is that the closing time and opening time of the circuit breaker under test fall between a few milliseconds and several hundred milliseconds, while the lower limit of the measurement range on some testers is too high, causing the measured values to fall into a range where errors are amplified. The KC-7900's mechanical switching time measurement range is 0.2–999.0 ms with a measurement error of ±5%, covering the operating time measurement requirements of vacuum circuit breakers, SF6 circuit breakers, and some low-voltage air circuit breakers. When selecting, confirm that the lower limit of the range is below the shortest operating time of the circuit breaker under test to avoid distortion in the measurement of small values.
Low-voltage operating tests require adjusting the voltage point by point and recording the operating value and return value; manual operation is time-consuming and consistency depends on the operator. This instrument provides a fully automatic low-voltage test function: simply set one voltage value, and the instrument automatically completes the operating voltage search and records the return voltage, reducing the workload of manual point-by-point adjustment. For batch sampling inspections or on-site verification tasks, this function helps shorten the test time per circuit breaker while reducing the impact of human reading differences on the results.
Switching characteristic tests are mostly conducted at substation sites or beside switchgear cabinets, where ambient temperature fluctuations can affect the stability of electronic measurement circuits. The instrument's operating ambient temperature starts at -10°C; when selecting, check whether the lower limit meets the requirements based on the lowest winter temperature at the project location; if used in colder environments, the storage and startup conditions of the instrument must be separately confirmed. Before on-site wiring, confirm that the sensor installation method matches the travel structure of the circuit breaker under test to avoid time and travel data deviations caused by installation gaps.
This instrument is suitable for power system maintenance, factory inspection by switch manufacturers, and periodic verification of power distribution equipment in industrial and mining enterprises. During configuration, design and selection personnel can list the number of time measurement channels, sensor types, and types of circuit breakers to be tested in correspondence, form a configuration list, and then check the range and error specifications. For applications where time parameters are the main criterion, priority should be given to confirming time measurement accuracy; for applications requiring analysis of travel characteristics, attention should also be paid to the resolution and installation compatibility of the travel sensor.
