UNI-T UT255A High Voltage Clamp Ammeters
The UNI-T UT255A High Voltage Clamp Ammeter is a handheld instrument ingeniously engineered for safe, on-line measurement of both AC leakage currents and line currents in high-voltage environments up to 60 kV. Its compact clamp-on jaw integrates a current transformer and a guide zone, allowing the operator to simply encircle the conductor positioned at the jaw’s center—for real-time current readings, while the integral insulation rod ensures user safety during live measurements.
The meter’s durable housing and precision CT circuitry deliver reliable detection of low-level leakage currents down to microampere ranges, making it particularly adept at assessing the condition of zinc oxide arresters by monitoring minute leakage flows that indicate moisture ingress or ageing. Ergonomic controls enable seamless transition between measurement modes general, peak-hold, and data-hold—so that transient spikes or sustained currents can be captured and retained without interrupting field operations.
Despite its rugged design, the UT255A remains lightweight and well-balanced, permitting extended use on transmission lines and outdoor installations. By combining intuitive clamp-on operation with high-voltage insulation and precise current sensing, the UT255A offers utility and maintenance personnel a versatile tool for diagnosing and monitoring the health of high-voltage systems.
Features:
- Auto range.
- 2×/s sampling rate.
- Peak-hold function.
- Manual ranging.
- RS-232 data interface.
- Data-hold capability.
- Over-range (“OL”) display.
- Auto power-off / LCD backlight.
- Low-battery indication.
- Overload protection.
- Automatic plug-clamp mechanism.
- Data recall.
- Test modes: Clamp-CT and integration.
- On-board storage: up to 99 data sets.
Specifications:
| Specification | Details |
|---|---|
| Measuring Capability: | AC leakage current and on-line current (clamp-type CT) indirect CT ratio measurement |
| Power Supply: | DC 6 V (4 × 1.5 V AAA alkaline batteries) |
| Measuring Modes: | General (real-time) Peak-hold Data-hold Data-save (up to 99 sets) |
| Display: | 4-digit backlit LCD; indicators for MEM, FULL, MR, HOLD, PEAK, OL A, no-signal |
| Sampling Rate: | 2 samples/second |
| Measuring Range & Resolution: | 0.01 mA – 600.0 A (auto-range) resolution: 10 µA |
| Accuracy: | ±(1% + 5 digits) up to 100 A ±(2% + 5 digits) 100 A–200 A ±(3% + 5 digits) 200 A–600 A |
| Jaw Opening (Guide Zone): | 33 mm |
| Live-Circuit Capability: | Measurement on systems up to 60 kV (with supplied insulation rod) |
| Auto Power-Off: | After 15 minutes of inactivity |
| Low-Battery Indication: | Display shown when battery voltage drops below 4.8 V |
| Overload/Over-Range Indication: | “OL A” icon |
| Weight: | Tester (with batteries): 335 g |
| Insulation Rods: | Five 1 m sections, Ø 32 mm; withstand AC 100 kV (rod-to-housing), AC 1 000 V (housing-to-core) |
| Environmental Conditions: | Operating: –20 °C to 60 °C, ≤ 70% RH; Storage: –20 °C to 40 °C, ≤ 80% RH |
| Interference Resistance: | No interference at 315 MHz or 433 MHz |
Applications:
- Live-line current and leakage detection.
- Condition monitoring of zinc oxide surge arresters.
- Inspection and maintenance of high-voltage electrical systems.
- On-site diagnosis of insulation faults.
- Detection of abnormal leakage currents.
- Verification of current transformer (CT) ratios.
- Power utility and industrial field work.
Package Include:
- 1x High-Voltage Clamp Ammeter (UT255A)
- 5x Insulation Rods – 1 m sections (Ø 32 mm)
- 4x AAA Alkaline Batteries (1.5 V LR03)
- 1x English User Manual
- 1x Gift Box / Tool Box
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