Loop Resistance Tester

The loop resistance tester is a high-precision, digital switch testing instrument meticulously developed by our company based on IEC standards and the latest power implementation standard of the People's Republic of China, DL/T845.4-2004, leveraging our technological advantages. This instrument employs high-frequency, high-power constant current switching power supply technology, capable of measuring micro-ohm level contact resistance. It is widely applicable to measuring the contact resistance, loop resistance, and contact resistance of various switches and electrical appliances, as well as cables, wires, and welds. The instrument provides accurate measurement data and stable performance, meeting the requirements of power supply departments for on-site high-voltage switch maintenance and high-voltage switch manufacturers for loop resistance testing. The output current and measured resistance are simultaneously displayed on a 7-inch high-brightness touchscreen color LCD. Measurement results can be output as voltage or stored on a USB flash drive; data can be retrieved at any time after power failure.

1.Remote Control via Mobile App: The instrument can be controlled via Android phones or tablets. By following our WeChat official account and downloading the dedicated APP, users can manage the entire testing process, with data stored and uploaded for easy access.

2.Comprehensive Protection System: Features multiple safeguards, including protection against back-EMF surges, wire breakage during testing, power outages, and power supply overheating. It reliably guards against back-EMF impacts and triggers a simultaneous audible alarm.

3.High Test Current: Delivers a high test current that fully complies with national standards for contact resistance testing.

4.Intelligent Power Management: Employs smart power management technology to ensure the instrument consistently operates at minimum power, effectively saving energy and reducing heat generation.

5.High Voltage & Wide Range: Offers a high output voltage and a wide measurement range.

6.Automatic Constant Current Supply: The test current is provided by a high-precision, high-current constant-power supply, requiring no manual adjustment and ensuring fast, accurate results.

7.Four-Terminal (Kelvin) Measurement: Utilizes four-terminal wiring to effectively eliminate the influence of test lead resistance on results.

8.High-Resolution Touch Display: Features a 65K-color, 7-inch high-brightness LCD touchscreen with a fine pixel array (320×240). It ensures clear visibility even in strong light, supports full touch operation, and allows free switching between Chinese and English interfaces.

9.Data Storage & Recall: Includes a built-in perpetual calendar clock and non-volatile memory, capable of storing 1,000 sets of test data for easy retrieval.

10.Versatile Connectivity: Equipped with Bluetooth, RS232, and USB interfaces for computer communication and data transfer via USB flash drives.

Integrated Printing: Comes with a built-in, panel-mounted mini printer for printing measurement results in Chinese.

To overcome the influence of the resistance of the test leads themselves and contact resistance, loop resistance testers generally employ the classic **Kelvin four-wire measurement method**.

Current Source (C1, C2): Outputs a constant large current (typically 50A, 100A, 200A or higher) through the circuit under test.

Voltage Detection (P1, P2): Precisely measures the voltage drop across the two ends of the object under test directly through two additional independent leads.

Calculation: The instrument's internal precision measurement system calculates the resistance value based on Ohm's Law, R = U / I. Because the voltage measurement circuit has extremely high input impedance, the current flowing through the voltage lines is almost zero, effectively eliminating the influence of test lead resistance and contact resistance on the measurement results, ensuring high measurement accuracy.

Taking a typical 100A loop resistance tester as an example:

Baoding Simaier Electric Co., Ltd.was established on July 1, 2009 and is located in the National High-tech Industrial Development Zone of Baoding City, Hebei Province. It is a high-tech enterprise focusing on the research and development of power system automation, relay protection and instrumentation.