MEWOI4660 / 4670 Transformer DC Resistance Testers (10A Microhmmeter)

A DC resistance tester (or microhmmeter) measures very low resistances accurately by passing a known DC current through the item and measuring the voltage across it with separate sense leads (the four-wire method). It is the standard tool for checking transformer winding resistance, and it is equally useful for grounding continuity, cable conductor resistance, switch, connector and relay contacts, motor and coil windings, welded and riveted joints, and battery interconnections.

MEWOI's testers deliver up to 10A at up to 24V, with automatic current selection to suit the load or seven manual current steps (10A down to 1mA). They measure from 1.0µΩ to 50kΩ with 0.1µΩ resolution, discharge the winding automatically after each test, and include an adjustable alarm threshold, wire-length calculation and temperature-corrected resistance. The instrument sits in a rugged IP65 waterproof case and runs from a built-in rechargeable lithium battery.

How to choose

All three share the same 10A test current and 1.0µΩ–50kΩ range. The MEWOI4660 is the standard model with an LCD display. The MEWOI4660C is a lighter handheld version with a 5-inch colour touch screen and a 16V output. The MEWOI4670 adds a 5-inch colour touch screen, mains (AC 220V) or battery operation and a built-in printer for on-site test records.

MEWOI4660 test current and accuracy

Resolution 0.1µΩ; four-wire measurement with dual simultaneous A/D; auto or manual mode (AUTO, 10A, 5A, 1A, 100mA, 10mA, 1mA); alarm threshold 1mΩ–2500Ω; wire length calculation up to 9999m; automatic discharge; 15-minute auto power-off. MEWOI4660 host 280 × 260 × 160mm, about 3.06kg (5.8kg with accessories); operating −10 to 40°C. Specifications from MEWOI's published data.

• 10A test current with automatic or manual current selection
• 1.0µΩ to 50kΩ range, 0.1µΩ resolution
• Four-wire measurement for accurate low-resistance readings
• Automatic discharge after each test
• Resistance alarm, wire length and temperature-corrected resistance
• IP65 waterproof case with rechargeable lithium battery
• USB and Bluetooth; printer on MEWOI4670

Transformer winding DC resistance; grounding continuity; cable conductor resistance; contact resistance of switches, connectors and relays; motor, coil and transducer windings; welded and riveted joints; battery interconnection resistance.

• DC Winding Resistance Testing — The Other Half of a Complete Transformer Test
• Transformer Turns Ratio Testing — What TTR Actually Verifies Before Energisation