Goldhome Welcomes Malaysian Client Delegation Contact Resistance Tester Emerges as Key Focus of Inspection
Recently, a delegation representing Malaysia's power sector visited Goldhome Hipot for an inspection tour. The company's General Manager, accompanied by the technical team, extended a warm welcome to the distinguished guests. Throughout the day-long visit, Guodian Huamei's independently developed contact resistance tester captured the delegation's sustained attention. Both parties engaged in in-depth discussions regarding the product's technical specifications, application scenarios, and compliance with international standards.
At the contact resistance tester demonstration area, the HM6090-200A high-precision model drew particular interest. Technical engineers showcased the equipment's core components: the main unit, specialised test leads, current output clamps, voltage measurement leads, and supporting accessories.
The principle of the four-terminal measurement method was the first key point explained by the technical engineers. " We employ the Kelvin four-wire measurement method, with current output and voltage measurement leads independently separated. This effectively eliminates the influence of test leads and contact resistance on measurement results, ensuring measurement accuracy at the microohm level." The engineer explained while pointing to the current output terminals (I+, I-) and voltage measurement terminals (V+, V-) on the device panel.
Regarding the current output section, the engineer demonstrated the device's constant current source technology: " Our contact resistance tester employs high-frequency switching power supply technology, delivering stable DC current outputs across four levels: 50A, 100A, 150A, and 200A. These outputs exhibit minimal ripple and exceptional stability.' The engineer switched the current setting to 100A, pressed the measurement switch, and the ammeter stabilised at '100.0", while the ohmmeter simultaneously displayed the resistance value of the standard resistor under test.
The client closely observed the device's stability during high-current operation, expressing appreciation for the smoothness and precision of the current output. The engineer elaborated: '100A high-current testing aligns with the recommended requirements of the power industry standard DL/T845.4-2004. Such high currents effectively break through the oxide film on switch contact surfaces, yielding the true contact resistance under operational conditions rather than the spurious resistance values presented by the oxide layer.'
Regarding measurement accuracy, the engineer outlined the equipment's core technology: 'We employ precision instrument operational amplifiers and high-accuracy quadruple-integrating A/D converters, integrated with a 16-bit high-performance microcontroller. This achieves a measurement resolution of 0.01μΩ and accuracy better than ±(0.5% rd + 2d).' The client reviewed the factory test report, meticulously verifying each accuracy specification.
Before discussing data management, the engineer demonstrated the device's storage and printing capabilities. Equipped with a large Chinese LCD display, it shows real-time parameters including current, resistance, and test duration. Its internal memory stores 200 test sets, supporting historical data review and power-off protection. The customer also inspected the integrated high-speed thermal printer, where the engineer printed a test report on the spot. The clear data formatting and comprehensive information left a strong impression.
Regarding safety protections, the engineer explained the device's over-temperature protection circuit: 'Should prolonged continuous operation cause internal temperatures to exceed safe limits, the protection circuit automatically cuts off output to safeguard both the equipment and personnel.' The USB port and RS232 communication interface on the device panel also drew the customer's attention. The engineer clarified these interfaces facilitate data export and communication with host computers, meeting the customer's requirements for laboratory information management.
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