Megger MIT1025 MIT Series Insulation Resistance Testers

Megger MIT1025/2 is a 10 kV Advanced insulation resistance tester designed for diagnostic testing and maintenance of high-voltage electrical equipment, including transformers, motors, switchgear, and cables . It is part of Megger's Advanced range of 5 kV, 10 kV, and 15 kV insulation testers, offering enhanced diagnostic capabilities, onboard storage, and data management features.

This instrument is 25% smaller and 35% lighter than previous generation models, making it more portable while maintaining rugged field durability .

Key Features

Feature Description

Maximum Test Voltage 10 kV

Maximum Resistance Measurement 20 TΩ

PI Predictor™ Patented technology that predicts 10-minute Polarization Index values in 3-5 minutes, cutting test time by more than 50%

RE>Act™ Mode Enhanced test mode that monitors reabsorption current for improved accuracy and safety; prevents incorrect pass/fail decisions due to residual current

Noise Immunity 6 mA interference rejection (from 960 V to 10 kV)

Data Management Built-in memory with time/date stamping; USB and Bluetooth® Class 2 connectivity

Safety Rating CAT IV 600 V up to 3000 m altitude

Protection Rating IP65 (lid closed), IP40 (lid open)

Power Supply Dual operation: Li-ion battery or AC mains (90-264 V, 47-63 Hz)

Technical Specifications

Insulation Testing

Parameter Specification

Fixed Test Voltages 500 V, 1000 V, 2500 V, 5000 V, 10000 V

User-Defined Voltage 50 V to 1000 V (10 V steps); 1000 V to 10000 V (25 V steps)

Test Voltage Accuracy +4%, -0%, ±10 V at 1 GΩ load (0°C to 30°C)

Resistance Range 10 kΩ to 20 TΩ

Resistance Accuracy ±5%: 2 TΩ at 10 kV, 1 TΩ at 5 kV, 500 GΩ at 2500 V

±20%: 20 TΩ at 10 kV, 10 TΩ at 5 kV, 5 TΩ at 2500 V

Digital Display Range 10 kΩ to 20 TΩ

Analog Display Range 100 kΩ to 10 TΩ

Short Circuit / Charge Current 1 mA, 3 mA (default), 6 mA at 5 kV/10 kV (6 mA only from mains supply)

Guard Terminal Performance Guards out current I_G ≥ 5000 × I_L at 100 GΩ / 5000 V with maximum error of 1%

Current Measurement

Parameter Specification

Current Range 0.01 nA to 6 mA

Current Accuracy ±5% ±0.2 nA at all voltages (20°C)

Noise Rejection 6 mA from 960 V to 10 kV

Capacitance Measurement

Parameter Specification

Capacitance Range 10 nF to 25 μF (with test voltage above 500 V)

Capacitance Accuracy ±10% ±5 nF

Capacitor Charge Time <5 s/μF at 3 mA to 10 kV

Capacitor Discharge Time <250 ms/μF to discharge from 10 kV to 50 V

Voltage Measurement

Parameter Specification

Voltmeter Range 30 V to 660 V AC/DC

Frequency Range 45 Hz to 65 Hz

Voltmeter Accuracy ±3%, ±3 V

Insulation Test Alarm

Parameter Specification

Alarm Range 100 kΩ to 10 GΩ

Test Modes

The MIT1025/2 supports a comprehensive suite of diagnostic test modes :

Test Mode Description

IR Basic insulation resistance

IR(t) Timed insulation resistance

DAR Dielectric Absorption Ratio

PI Polarization Index

SV Step Voltage

DD Dielectric Discharge

PDC Polarization/Depolarization Current (requires software)

Ramp Test Ramp test mode

Burn Mode Available for breakdown testing

Power Supply

Parameter Specification

Battery Type 10.8 V, 5.2 Ah Li-ion (meets IEC 62133:2003)

Battery Life 4.5 hours (typical) continuous testing at 10 kV with 100 MΩ load

Quick Charge 30 minutes charge provides 1 hour operation at 5 kV with 100 MΩ load

Full Charge Time 2.5 hours (deep discharge), 2 hours (normal discharge)

AC Input 90-264 V rms, 47-63 Hz, 100 VA

Line Operation Operates directly from AC mains even with completely dead battery

Memory & Interfaces

Parameter Specification

Memory Capacity 5.5 hours logging at 5-second intervals

Data Storage Test results with date and time stamp

Interfaces USB Type B (device), Bluetooth® Class 2 (range up to 10 m)

Real Time Output 1 Hz output readings (V, I, R)

Timer Range Up to 99 minutes 59 seconds (15 seconds minimum setting)

Environmental Specifications

Parameter Specification

Operating Temperature -20°C to 50°C

Storage Temperature -25°C to 65°C

Humidity 90% RH non-condensing at 40°C

Maximum Altitude 3000 m

IP Rating IP65 (lid closed), IP40 (lid open)