Accredited Insulation Tester Calibration Services
The reliability of electrical insulation is the primary safeguard against short circuits, equipment fires, and electrical shock. At DRS Technologies, we provide expert insulation tester calibration services to ensure your Megohmmeters and high-voltage testers provide the precise data required for preventative maintenance. Our laboratory verifies that your equipment maintains the accuracy necessary to detect insulation breakdown before it leads to system failure.
Why Precise Insulation Testing is Critical for Safety Compliance
Insulation testers operate by applying high DC voltages to measure extremely high resistance values. Over time, internal voltage regulators and leakage current sensors can drift, leading to over-optimistic readings that hide dangerous insulation thinning. Regular calibration by DRS Technologies ensures your tools meet the rigorous requirements of ISO 9001 and OSHA safety standards, providing a legally defensible record of your safety testing accuracy.
Our Technical Calibration and Verification Process
Our metrology specialists follow a high-precision protocol to verify both the sourcing and measuring capabilities of your instrument:
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High-Voltage Output Verification: We measure the actual voltage produced by the tester at every setting (e.g., 250V, 500V, 1000V, 5000V) to ensure it reaches the nominal value without excessive ripple.
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High-Resistance Linearity Testing: Using specialized high-voltage decade boxes, we verify the meter’s accuracy across the Teraohm ($\text{T}\Omega$) and Gigaohm ($\text{G}\Omega$) ranges.
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Leakage Current Accuracy: We verify the instrument’s ability to measure minute leakage currents, which is essential for calculating the Polarization Index (PI) and Dielectric Absorption Ratio (DAR).
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Safety and Discharge Function Audit: We test the instrument’s internal discharge circuitry to ensure it safely bleeds off residual capacitive charges from the test leads after a measurement is completed.
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Certification and NIST Traceability: Every service includes a comprehensive calibration certificate featuring as-found/as-left data, uncertainty measurements, and documented NIST traceability.
Comprehensive Support for All High-Resistance Instruments
DRS Technologies services a wide array of insulation testing technology, including:
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Handheld Digital Megohmmeters
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High-Voltage Insulation Resistance Testers (up to 15kV)
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Analog Insulation Testers and Hand-Crank Meggers
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Combined Insulation and Continuity Testers
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Hipot and Dielectric Strength Testers
Frequently Asked Questions Regarding Insulation Tester Calibration
What is the difference between an insulation tester and a standard ohmmeter?
A standard ohmmeter uses low voltage to measure resistance, whereas an insulation tester (Megohmmeter) applies a high voltage (usually 500V or higher) to “stress” the insulation. Calibration at DRS Technologies ensures that the high-voltage source is accurate and that the leakage current detection is sensitive enough to measure resistance in the Gigaohm range.
How often should an insulation tester be calibrated?
The industry standard for insulation tester calibration is twelve months. Because these tools are often used in demanding field environments where they are subject to temperature swings and mechanical vibration, annual verification is essential to ensure the internal high-voltage transformers haven’t drifted.
What are PI and DAR in insulation testing?
The Polarization Index (PI) and Dielectric Absorption Ratio (DAR) are ratios of insulation resistance measured over specific time intervals. These ratios are more informative than a single reading for determining the health of motor windings. Calibration at DRS Technologies ensures the internal timer and measurement stability are accurate enough to produce reliable PI and DAR results.