Electrical Resistance Tester
-Test to make sure your wire meets the IEC, NEMA and DIN standards!
An electrical resistance tester measures the electrical resistance of magnet wire, which is thin, insulated copper or aluminum wire used in coils, motors, and transformers. This testing ensures the wire meets standards like NEMA or ASTM by verifying conductor quality, purity, and dimensions, often using a fixed 1-meter sample.
How the test works
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Expose bare conductor
The enamel is scraped or stripped off at the ends of the wire so the tester clips or probes contact bare metal, not the coating. -
Measure DC resistance
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The tester sends a known, small test current through a known length of the wire (often 1 m sample) at room temperature.
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It measures the voltage drop and computes the resistance of that length.
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The measured resistance is then compared with the expected value for that wire size and material, often normalized to 20 °C using a temperature-correction formula.
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What the result tells you
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If resistance is too high, the wire might be too thin, made from the wrong alloy, or damaged.
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If resistance is too low, the diameter may be larger than specified or there could be manufacturing issues affecting conductor size.
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Simple example
If you had 1 m of enameled copper wire, you would scrape the enamel off both ends, connect it to the resistance tester, read the resistance value (for example, a few milliohms), and compare it to tables for that wire gauge at 20 °C to confirm the conductor is correctly sized and continuous, while separate insulation tests would confirm the enamel itself is not leaking or breaking down.
Key Features
Devices like the OHM2, OHM3, OHM3A and OHM4 handle magnet wire from 0.025 mm to 3,15 mm, and include temperature compensation for materials like copper.
Purpose in Quality Control
Resistance data helps calculate wire length, cross-section, or detect defects like impurities; low resistance indicates pure, properly sized conductors.
For more information read the datasheet here. Or contact our sales department.
