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MI-2550e General Purpose Insulation Tester

The MI‑2550e is a general-purpose, portable insulation resistance tester, designed for accurate measurements of ultra-high insulation resistances up to 5,000,000 MΩ (5 TΩ) using four selectable test voltages: 0.5 kV, 1 kV, 1.5 kV, and 2.5 kV.

Like its higher-voltage sibling, the MI‑2550e uses true analog technology favored by experienced technicians. The analog pointer provides real-time movement that offers valuable insights into insulation behavior — particularly useful during long-duration or time-varying measurements.

Compact, lightweight, and field-ready, this tester is built for reliability in a wide range of applications including electrical systems, motors, transformers, cables, electro-medical installations, and more.

Key Features

  • Insulation testing up to 5 TΩ

  • Four test voltages: 0.5 kV, 1 kV, 1.5 kV, 2.5 kV

  • Analog display with taut-band mirror scale to reduce parallax error

  • GUARD terminal for eliminating parasitic resistance effects

  • IP65-rated enclosure (with lid closed)

  • Visual voltage warning indicator and automatic discharge function

  • Rechargeable battery for field operation

  • Rugged and weather-resistant case for outdoor use

Technical Specifications

Test Voltages

  • 0.5 kV, 1 kV, 1.5 kV, 2.5 kV

Maximum Resistance Readings

  • 1 TΩ @ 0.5 kV

  • 2 TΩ @ 1 kV

  • 3 TΩ @ 1.5 kV

  • 5 TΩ @ 2.5 kV

Short Circuit Current

  • 1 mA ± 2%

Test Voltage Accuracy

  • ± 2% of nominal test voltage (on R ≥ 1 GΩ)

Current Limiting Resistance

  • 500 kΩ @ 500 V

  • 1 MΩ @ 1 kV

  • 1.5 MΩ @ 1.5 kV

  • 2.5 MΩ @ 2.5 kV

Insulation Tester Accuracy

  • Class 2 (±2% of full-scale deflection)

Analog Indicator

  • Scale length: Up to 98 mm

  • Taut band with mirror scale (minimizes parallax)

Environmental Protection

  • IP65 (with closed lid)

Compliance and Safety

  • IEC 61010-1 (Safety Class)

  • IEC 61326-1 (EMC)

  • IEC 61000-4-3 (Electromagnetic Immunity)

  • IEC 61000-4-2 (Electrostatic Immunity)

Power Supply

  • Internal 12 V / 2.3 Ah sealed lead-acid rechargeable battery

  • Charger input: 100–240 V AC

Temperature & Humidity

  • Operating: -10 °C to 50 °C (14 °F to 122 °F)

  • Storage: -25 °C to 70 °C (-13 °F to 158 °F)

  • Humidity: Up to 95% RH (non-condensing)

Physical

  • Weight: Approx. 8.6 lb (3.9 kg)

  • Dimensions: 10.78" x 9.84" x 4.88" (274 x 250 x 124 mm)

Application

  • Electrical systems (low and medium voltage)

  • Transformers

  • Motors and cables

  • Electro-medical equipment

  • Distribution networks

Included Accessories

  • 2 Measuring test leads

  • 1 GUARD test lead

  • 1 Power cord

  • 1 Carrying bag

  • 1 Operating instructions manual

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