1、 Daily appearance and basic inspection (must be done before each use)

Appearance integrity inspection

Check whether the instrument casing, display screen, and operation buttons are damaged, cracked, or deformed; Check whether the insulation layer of the test line (including high-voltage output line, ground wire, and probe) is aging, damaged, or exposed, and whether the plug/clip is corroded or has poor contact. If damage is found, replace it with accessories that meet the specifications in a timely manner (avoid using non original non-standard test lines to prevent safety risks caused by mismatched insulation levels).

Inspection of connection parts

Check if the test line interface and power interface on the instrument are loose or oxidized. Use a dry cloth dipped in anhydrous alcohol to wipe the interface contacts, remove dust and oxide layer, and ensure reliable connection.

2、 Function and performance verification (regular execution, recommended once a month)

Power system inspection

If it is a portable battery powered instrument: check the battery level (determined by the instrument's power indicator light or display screen prompt), and charge it once a month when not in use for a long time to avoid battery depletion and aging; After the battery's service life expires (usually 2-3 years), replace it with a qualified battery of the same model in a timely manner, and dispose of old batteries according to environmental protection requirements.

If it is an AC power supply instrument: Use a multimeter to check whether the output voltage of the power adapter meets the rated requirements of the instrument (such as 12V/2A, etc.), to avoid unstable power supply caused by adapter failure.

Zero point and basic accuracy verification

Short circuit the "L" (line end) and "E" (ground end) of the test line, set the instrument to the lowest insulation resistance level (such as 100 Ω), and the displayed value should be close to 0 Ω. Confirm that the zero point of the instrument is normal;

Use a standard resistance box (with an accuracy not lower than one level of instrument accuracy) for calibration: connect the standard resistance (such as 10M Ω, 100M Ω, 1G Ω) to the "L" and "E" terminals, and the instrument display value should be within the allowable error range of the standard resistance (if the instrument accuracy is ± 5%, the deviation between the display value and the standard value should be ≤ 5%). If it exceeds the tolerance, contact a professional organization for calibration.

High voltage output safety check

Start the instrument and output the low voltage gear (such as 250V) without load. Use a qualified high voltage tester to lightly touch the output end of the test line to confirm the presence of high voltage output; At the same time, observe whether there are any abnormal sounds, odors, or flashing displays on the instrument. If any abnormalities occur, immediately power off and stop the machine.

3、 Core component maintenance (once every quarter, or adjusted according to usage frequency)

Display screen and button maintenance

When there is dust on the surface of the display screen, gently wipe it with a dry soft cloth (such as suede cloth). Do not use organic solvents such as alcohol and gasoline to avoid corroding the screen coating; If there are stains, they can be wiped with a small amount of water and immediately wiped dry.

If the operation buttons are stuck or unresponsive, the instrument panel can be opened (power off operation is required), and the dust in the gaps of the buttons can be cleaned with a brush. Apply a small amount of conductive paste (such as graphite paste) to the button contacts to enhance conductivity.

Internal cleaning and moisture prevention

Disassemble the instrument casing (to be operated by professionals), use compressed air (pressure ≤ 0.3MPa) to blow away dust on the internal circuit board and fan (if any), to avoid poor heat dissipation or short circuit caused by dust accumulation;

If the instrument is used in a humid environment for a long time (relative humidity>80%), a small desiccant pack (such as silicone desiccant) can be placed inside and replaced regularly to prevent the circuit board from being corroded by moisture.

Test clip/probe maintenance

If the metal contacts of the test clip are corroded, gently polish them with fine sandpaper (400 mesh or more) until they are shiny, and then apply a thin layer of Vaseline for rust prevention;

If the probe wire shows slight aging, it can be temporarily protected by wrapping insulation tape. If the aging is severe, it needs to be replaced immediately to ensure insulation safety during testing.

4、 Storage and Idle Management (Key Focus When Not Used for a Long Time)

Storage environment requirements

Store the instrument in a dry, ventilated, and non corrosive gas environment, with a temperature controlled between -10 ℃ and 40 ℃ and a relative humidity of ≤ 70%; Avoid direct sunlight, proximity to heat sources (such as heaters, ovens), or strong electromagnetic fields (such as transformers, welding machines) to prevent component aging or performance interference.

Idle pre-processing

Disconnect all test lines, turn off the instrument power, and remove the built-in battery (if powered by a battery) to avoid battery leakage and corrosion of the circuit board;

Cover the instrument with a dust cover to prevent dust from entering the interior; The test line should be organized and stored separately to avoid internal core breakage caused by folding and squeezing.

Regular activation (idle for more than 3 months)

Start up and run once a month, switch to different gears without load, run for 10-15 minutes each time, use the instrument's own heat to remove internal moisture, and activate electronic components to prevent performance degradation.

5、 Common problem handling and precautions

Prohibit illegal operations

It is strictly prohibited to plug or unplug the test line or touch the output end of the test line with hands during the high voltage output of the instrument to prevent electric shock;

It is strictly prohibited to conduct over range testing (such as testing equipment with a rated insulation voltage of 500V using the 1000V gear) to avoid instrument overload damage.

Principles of fault handling

If the instrument encounters the following situations, it is prohibited to disassemble and repair it by oneself. Contact the manufacturer or a qualified metrology institution for handling:

No response upon startup, black screen or garbled text on the display screen;

Serious deviation in test data (confirmed by standard resistance verification);

Sparks, abnormal noises or smoke appear when outputting high voltage.

calibration cycle

According to the metrological regulations, the insulation resistance tester needs to be sent to a legal metrology institution for mandatory calibration once a year to ensure that it meets the requirements of standards such as GB/T 16927.1-2011. Only after passing the calibration can it continue to be used.

Through standardized daily maintenance, not only can the service life of the insulation resistance tester be extended, but the accuracy of its measurement data can also be guaranteed, providing reliable support for the insulation status assessment of power equipment.