I. Overview

The insulation resistance meter (megohmmeter) is a nationally mandatory verification measuring instrument, with its verification regulation being JJG622-89. The main standard devices of the verification device are the high-voltage high-resistance box and the high-voltage voltmeter. The ZX119-8 Megohmmeter Verification Device integrates the high-voltage high-resistance box (high-resistance output part) and the high-voltage digital voltmeter (voltage input part) into one unit.

The measurement upper limit of the resistance output part in the verification device is 100 GΩ, with a nominal working voltage of 5 kV. The device is designed with independent leakage terminals and grounding terminals, showing no significant instability, short circuit, or open circuit phenomena during measurement. It meets the requirements of the JJG622-97 Insulation Resistance Meter Verification Regulation and the JJG166-93 DC Resistor Verification Regulation. It can be used for the verification of various models of pointer-type insulation resistance meters.

The resistance output part of the verification device uses a patented rolling high-voltage switch, which can still meet the verification regulation requirements after 100,000 uses. It has a long technical life and mechanical life. The nominal measurement voltage of the voltage measurement part in the verification device is 5 kV, with an input impedance ≥10 GΩ. This device can measure the open-circuit voltage, median voltage, and peak voltage of the megohmmeter.

II. Main Technical Parameters

1. Resistance Output (High-Voltage High-Resistance Box) Part

1.1 Accuracy Class and Working Voltage (Current) of the Resistance Output Part 

1.2 Adjustment Range: 100 Ω to 100 GΩ, with an adjustment resolution of 100 Ω

1.3 Operating Environmental Conditions

1.3.1 Reference Temperature Range: 20 to 25°C   

1.3.2 Nominal Operating Temperature Range: 18 to 28°C       

1.3.3 Reference Humidity Range: 40 to 60%

1.3.4 Nominal Operating Humidity Range: 25 to 75%

1.4 Resistance Variation Limit: Under reference conditions, the variation caused by a change in a single influencing factor

★ a is the accuracy class of the resistance dial in the resistance output part of the verification device (the a value varies for different resistance dials)

1.5 Insulation Resistance: The insulation resistance between the circuit of the resistance output part of the verification device and any other external metal without electrical connection, measured at the nominal voltage, shall be not less than 5 TΩ.

1.6 Insulation Strength: Between the circuit of the resistance output part of the verification device and the reference grounding point for testing, it should withstand an actual sinusoidal AC voltage of 11 kV at a frequency of 45 to 65 Hz for 1 minute without breakdown or flashover.

1.7 The residual resistance at the output terminals of the resistance output part of the verification device should be <0.1 Ω, with a variation of <0.01 Ω.

1.8 Dimensions: 442 mm × 270 mm × 145 mm

1.9 Weight: <5 kg

2. Voltage Measurement (High-Voltage DC Digital Voltmeter) Part

2.1 Measurement Range: 0 to 5500 V

2.2 Accuracy: ±(1% of reading ±1 digit)

2.3 Power Supply: DC 9 V

2.4 Input Resistance: ≥10 GΩ

2.5 Display: Four and a half digits, LCD display

2.6 The peak voltage measurement circuit meets the requirements of Figure 3 in the JJG622-97 Insulation Resistance Meter Verification Regulation.