MEWOI4800A / 4800B Lightning Protection Component (SPD) Testers
Field testers for surge protective devices: varistor (MOV) U1mA voltage and leakage current, and gas discharge tube DC breakdown voltage. The 4800B adds 500V/2500V insulation resistance.
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Overview
Surge protective devices degrade with every surge they absorb. A metal oxide varistor that has aged shows a falling initial action voltage (U1mA) and rising leakage current, and a gas discharge tube's DC spark-over voltage drifts. The MEWOI4800 testers measure these parameters on site, so SPDs in switchboards, telecom equipment and lightning protection systems can be checked rather than assumed to be healthy.
The instrument applies a controlled DC voltage ramp with short-circuit and over-current protection, measures U1mA from 50V to 3000V and leakage current at 0.75×U1mA from 0 to 1000µA, and measures GDT DC breakdown voltage at 100V/s. Pass limits, ramp speed and voltage limits can be set, and a continuous mode speeds up batch testing of components. Results (up to 3000) are stored and exported over USB. A colour touch screen with built-in help and a rechargeable lithium battery make it practical in the field.
The MEWOI4800B adds insulation resistance testing at 500V and 2500V for checking SPD and arrester insulation.
Key Specifications
| Measurement | Range | Accuracy | 4800A | 4800B |
|---|---|---|---|---|
| Varistor initial action voltage U1mA | 50–3000V | ±2%rdg ±3dgt | ✓ | ✓ |
| Varistor leakage current at 0.75×U1mA | 0–1000µA | ±2%rdg ±10dgt | ✓ | ✓ |
| Gas discharge tube DC breakdown voltage | 50–3000V | ±2%rdg ±3dgt | ✓ | ✓ |
| Insulation resistance at 500V | 0.5MΩ–2GΩ | ±5%rdg ±10dgt | — | ✓ |
| Insulation resistance at 2500V | 2.5MΩ–10GΩ | ±5%rdg ±10dgt | — | ✓ |
| General | Value |
|---|---|
| Test conditions | Varistor 1mA ±5µA; GDT ramp 100V/s ±10% |
| Display | Colour touch screen, 108 × 65mm, built-in help |
| Memory / interface | 3000 records; USB upload |
| Power | 7.4V 2600mAh rechargeable Li-ion |
| Size / weight | 212 × 175 × 76mm / approx. 1.2kg (4800A) |
Features
- Tests MOV varistors and gas discharge tubes
- U1mA, leakage current and DC breakdown voltage measurement
- Settable ramp speed, voltage limit and pass/fail limits
- Single and continuous modes for batch testing
- 3000-record memory with USB export
- 4800B: 500V and 2500V insulation resistance
- High-voltage short-circuit and over-current protection
Applications
In-service checking of surge protective devices in switchboards and telecom sites; lightning protection system maintenance; incoming inspection and production testing of varistors and GDTs; meteorological and power utility lightning protection inspection.