Resistance Tester

A: Measuring very low resistances (below 1 ohm) using standard two-wire meters introduces significant error due to the electrical resistance of the test leads and contact points. A four-wire Kelvin setup separates the current-carrying leads from the potential (voltage-sensing) leads, eliminating lead resistance from the calculation and ensuring true sample measurement accuracy.

A: Large power transformers store substantial magnetic energy during high-current testing. Our resistance testers incorporate automatic discharge circuitry with built-in surge suppression and counter-EMF clamping diodes that safely dissipate stored energy through internal dump resistors before the test leads can be disconnected.

A: Direct current flowing through a transformer core during winding resistance testing can leave residual magnetism in the silicon steel core. This residual magnetism can cause high inrush currents upon re-energization or distort transformer protection relay responses. The automatic demagnetization feature applies a decaying alternating or reversing current to clear residual core flux after the test finishes.

A: Yes. Our portable micro-ohm meters and 10A models include high-capacity internal lithium-ion battery packs capable of performing up to 400 continuous test cycles on a single charge, removing the need for AC line power during remote outdoor yard maintenance.

A: An annual calibration interval is recommended to maintain compliance with ISO 9001 and ISO/IEC 17025 internal audit requirements. Recalibration can be executed using certified low-ohm resistance standards or through authorized service centers.

A: Standard portable and 50A resistance testers ship within 5 to 7 business days. Multi-channel automated test systems or units requiring specialized communication protocols require 2 to 3 weeks for custom assembly and factory calibration.