Megger MIT1525 15 kV DC Insulation Resistance Tester

Category: Megger
  • Insulation resistance up to 30 TΩ @ 10 kV enables installation testing and long-term trending of higher value apparatus, typically above 1 TΩ.
  • High altitude operation up to 3000 m while maintaining CATIV 1000 V (15 kV).
  • 5% accuracy all the way up to 3 TΩ @ 15 kV ensures highest accuracy where it matters most.
  • IR, timed IR, DAR, PI, DD, SV and ramp tests maximize diagnostic testing capability.
  • 3 mA short circuit current with unique max power regulations technology ensures maximum transfer whatever the load until selected voltage is reached.
  • Noise filter rejects up to 6 mA (15 kV) noise for effective operation in electrically noisy environments.
  • Li-ion battery allows up to 6 hrs continuous testing @ 5 kV with a 100 MΩ load; battery meets IEC 62133.
  • Dedicated voltmeter function (30 V to 660 V) allows the user to check for induced volages.
  • Smaller size and lighter weight allows easier transport and use without compromising performance.
  • Unique dual case design allows for fire-retardant protection while maintaining ruggedness.
  • High-quality, flexible silicon test leads meet safety regulations of IEC 61010-31:2008.
  • Timed IR plus PI, DAR, DD, SV and ramp tests maximize diagnostic testing capability.
  • Operate from line power even if the battery is fully discharged (charges while operating).
  • Two and half hour full battery charge time (one-half hour charge for one hour testing)
  • Up to six hours continuous testing (5 kV) on a single battery charge.
  • Large backlit LCD clearly shows analog and digital readings.
  • Industry best guard terminal performance to insure highest accuracy of measured values.
  • Enhanced driver technology provides plug-and-play when connected to the internet.
  • Rotary switch operation for easy, intuitive field use.
  • Locking test leads provide additional safety.
  • Date and time-stamped test results reduce the risk of error in result interpretation.

    The top of the range Megger MIT1525 performs insulation resistance tests up to 15 kV with a 30 TΩ maximum resistance and an accuracy of ±5% to 3 TΩ. The Megger MIT1525 has a full suite of test modes as well as on-board memory and the ability to stream data/download data to a PC/laptop.

    Instrument productivity is a focus of the Megger MIT-1525 range which offers rapid charge batteries and operation from an AC source if the batteries are dead. Rapid charge batteries enable 60 minutes testing after a 30 minute charge.

    Safety is not compromised on the Megger MIT 1525's range with all terminals rated to CATIV 1000 V to 3000 m (15 kV). A range of 5 kV and 10 kV test leads are available plus dedicated 15 kV test leads which are double insulated with clips designed for 15 kV creepage paths. The Megger MIT 1525's 15 kV leads are supplied in a backpack. Depending on local procedures or the results of a risk assessment, suitably rated HV gloves and other personal equipment may be a requirement while testing.

    The Megger MIT/1525 range share dual case design which includes a tough outer case to protect the tester from knocks/drops and an inner fire retardant case. The IP rating is IP 65 case closed eliminating moisture and dust ingress.

    An intuitive user interface ensures no lost time remembering how to use the Megger MIT1525 tester. Simplicity of operation is achieved with two rotary switches and the large backlight display which enables multiple results to be displayed simultaneously. A graphical quick start guide is provided inside the lid of the Megger MIT1525 to assist first time users.

    Five preset voltage ranges are provided with the Megger MIT 1525 in insulation test mode, plus a user settable lock voltage range. Voltage can be selected in 10-V increments to 1 kV and 25-V increments above 1 kV. Pre-configured diagnostic tests include Polarization Index (PI), Dielectric Absorption Ratio (DAR), dielectric discharge (DD), Step Voltage (SV) and ramp test.

    The ramp function gradually increases voltage up to a selected level while graphing current vs. voltage. Graphs can then be downloaded, or streamed real time, to either the Power DB Lite software supplied with the Megger MIT1525 or the optional Power DB software. Graphs can then be compared to example curves in IEEE 95-2002 to reveal a variety of faults difficult to detect otherwise. Small defects can be easily detected without risking the sudden large voltage increments produced by a Step Voltage test. Monitoring the developing graph during test enables the operator to terminate prior to breakdown, thereby reducing the possibility of damage to already flawed insulation. These units are particularly informative on polyester, asphalt and epoxy-mica insulations. They can also test voltage suppression devices.

    Advanced memory storage includes time/date stamping of results, logging of data and recall of results to screen. A fully isolated USB interface is used for safe transfer of data to Megger’s asset management software; PowerDB Pro, Advanced and Lite packages.

    Test leads are double insulated with clamps rated at 3 kV equivalent to 6 kV single insulation for the medium clip leadset and 5 kV equivalent to 10 kV single insulation for the large clip. The 15 kV leadset is insulated to 15 kV.

    Applications
    The Megger MIT-1525 Insulation Resistance (IR) test is a quantitative test which indicates the effectiveness of a product’s electrical insulation. Applications include cables, transformers, motors/generators, circuit breakers and bushings.

    The Megger MIT1525 is designed for testing the insulation of high-voltage electric equipment. Their wide voltage range also allows applications for low-voltage equipment. The test techniques on the instruments provide valuable diagnostic information.

    The Megger MIT 1525 tests the insulation resistance of:
    • High-voltage power cables and high-voltage buses
    • Large motor/generator windings
    • Line and substation transformers
    The Megger MIT1525 also perform spot tests, step-voltage tests, dielectric discharge tests, ramp tests, and dielectric absorption tests for the following applications:
    • Acceptance testing at installation to check conformance to specifications.
    • Routine preventive/predictive maintenance testing after installation.
    • QA testing as part of the manufacturing process.
    • Diagnostic testing to isolate faulty components for repair.

    15 kV Insulation Testing
    A 15 kV insulation test is recommended for higher voltage electrical equipment. The Pearl Reconditioning Standard / NETA MTS-1997 defines both the minimum dc test voltage and minimum recommended insulation resistance based on the maximum voltage rating of the equipment being tested. For equipment rated from 35 kV to 69 kV, 15 kV dc test voltage should be used. The minimum recommended insulation resistance is 100 GΩ.

    NETA ATS 2007 Section 7.15.1 defines test voltage and minimum insulation resistance for ac induction motors and generators. If the voltage rating of motor’s winding is 34.5 kV, a 15 kV dc test voltage should be used. Again, the minimum recommended insulation resistance is 100 GΩ.

    The Megger MIT1525 maintains ±5% accuracy up to 3 TΩ, which is well above the minimum recommended insulation resistance level in both standards.

    Specifications
    Electrical Specifications
    Voltage input range: 15 kV Battery 90-264 V rms, 47-63 Hz, 200 VA
    2 battery pack
    Battery charge time: 2.5 hours from deep discharge, 2 hours normal discharge
    Lock test voltage V 40 V to 1 kV in 10 V steps,
    1 kV to 5 kV in 25 V steps,
    5 kV to 15 kV in 25 V steps
    Voltage o/p accuracy: +4%, -0%, ±10 V nominal test voltage at 1GΩ load (0°C to 0°C)
    Resistance Range: 10 k to 10 TΩ @ 5 kV
    10 k to 20 TΩ @ 10 kV
    10 k to 30 TΩ @ 15 kV
    Accuracy (23 °C) ±5% to 3 TΩ, ±20% to 30 TΩ
    Centrally positioned guard ring Guard parallel leakage, resistance down to 250 kΩ with a maximum additional resistance error of 1% with a 100 MΩ load.
    Display range analog 100 kΩ to 10 TΩ
    Display range digital 10 kΩ to 30 TΩ
    Short circuit current 3 mA @ 5 kV, 10 kV, 15 kV
    Insulation alarm 100 kΩ to 10 GΩ
    Capacitor charge < 3 s/μF to 5 kV, < 5 s/μF to 10 kV, < 7.5 s/uF to 15 kV
    Capacitor discharge 5 kV to 50 V :< 120 ms/μF
    10 kV to 50 V:< 250 ms/μF
    15 kV to 50 V:< 3500 ms/μF
    Capacitance range
    (> 500 V)
    10 nF to 50 μF (dependent on measurement voltage)
    Capacitance accuracy
    (23 °C)
    ±10% ±5 nF
    Current measurement range 0.01 nA to 6 mA
    Current measurement accuracy ±5% ±0.2 nA at all voltages (23 °C)
    Interference (noise) rejection 6 mA from 2100 V to 15 kV
    Voltmeter range 30 V to 660 V ac or dc, 45Hz – 65Hz
    Voltmeter accuracy ±3%, ±3V
    Timer range Up to 99 minutes 59 seconds, 15 second minimum setting
    Memory capacity 5.5 hours logging @ 5 sec intervals
    Test regimes IR, IR(t), DAR, PI, SV, DD, ramp test
    Interface USB type B (device)
    Real time output 1 Hz output readings (V, I, R)
    Environmental Specifications
    Altitude 3000 m
    Operating temperature -4° F to +122° F (-20° C to 50° C)
    Storage temperature -13° F to +149° F (-25° C to 65° C)
    Humidity 90% RH non-condensing at 40 °C
    Ingress protection IP65 (lid closed), IP40 (lid open)
    General Specifications
    CAT Rating CATIV 1000 V to 3000 m (15 kV)
    EMC Meets the requirements of IEC 61010-1 and IEC61326-1
    Dimensions
    (L x W x H)
    14 x 12 x 8 in. (360 x 305 x 194 mm)
    Weight 14 lb (6.5 kg)
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