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The loop resistance tester, also known as a micro-ohmmeter or contact resistance tester, is a meticulously developed instrument specifically designed for measuring various high-voltage switch contact resistances, high-voltage circuit breaker contact resistances, metal welded component connection resistances, metal conductor loop resistances, and precision micro-ohm resistances.

| Function | Various contact resistance tests for high-voltage switches, high-voltage circuit breakers, etc.; metal welded component connection resistance test; various loop resistance tests for metal conductors; precision micro-ohm resistance test |
| Power Supply | Built-in: 10.8V 4000mAh rechargeable lithium battery |
| Test Method | 4-wire method |
| Charger | 10.8V charger |
| Display Mode | 5.6-inch industrial-grade high-brightness color LCD screen |
| Test Interface | C1 (Current Positive), C2 (Current Negative), U1 (Voltage Positive), U2 (Voltage Negative) |
| Current Output | Coarse adjustment: ≤5A, 10A, 30A, 50A, 80A, 100A, 200A, 220A Fine adjustment: step value 2.5A, up to 87 current levels |
| Range | ≤5A: 1μΩ~3500mΩ 10A: 0.1μΩ~200mΩ 30A: 0.1μΩ~20mΩ 50A: 0.01μΩ~15mΩ 80A: 0.01μΩ~10mΩ 100A: 0.01μΩ~5mΩ 200A: 0.01μΩ~600uΩ 220A: 0.01μΩ~500uΩ |
| Minimum Resolution | 0.01μΩ |
| Test Accuracy | Current 30A~220A: ±(reading × 0.1% + range 0.2% + 1μΩ) Current 10A or ≤5A: ±(reading × 0.5% + range 0.2% + 10μΩ) |
| Test Time | ≤100A: Fast (recommended), 10s, 20s, 30s, 40s, 50s, 60s >100A: Fast |
| Data Storage | Data automatically saved after test, cyclic storage, up to 999 data sets |
| Instrument Dimensions | Approx. 229mm (L) × 166mm (W) × 73mm (H) |
| Weight | Instrument weight: approx. 2kg |
| Test Leads | Standard length: 3m (5m optional) Current and voltage separated test leads, simple wiring, resistance less than 10mΩ |
| Data Deletion | Select format memory option in settings to delete all data |
| Data Review | Enter data review interface, use up/down/left/right keys to browse stored data |
| Auto Power Off | Yes |
| Battery Voltage | Battery level indicator on instrument corner |
| Backlight | Adjustable brightness |
| Operating Current | Non-test state: 200mA Test state: operating current can be set manually |
| Circuit Protection | Open circuit protection, overheat protection, etc. |
| Temperature Protection | Temperature monitoring inside the instrument |
| Operating Temp/Humidity | -10℃~50℃; below 90% RH, no condensation |
| Storage Temp/Humidity | -10℃~60℃; below 70% RH |
| Applicable Safety Standards | IEC61010-1, CAT Ⅲ 600V, Pollution Degree 2, JJG724-1991, JJG166-1993, DL/T967-2005 |
| Model | ES3090 | ES3090E |
|---|---|---|
| Max Test Current | 100A | 220A |
| Note | Current above 100A only supports fast mode |
| Cloth Bag | 1 pc |
| Tester | 1 unit |
| Test Leads | 1 set (red, black 3m each) |
| Self-Test Resistor | 1 pc |
| Charger | 1 pc |
| User Manual / Warranty Card | 1 set |