Products Description
Equipment for measuring resistance
The contact circuit resistance tester, also known as the loop resistance tester or the high current micro-ohmmeter, is a specialized device used for measuring the contact resistance of high and low voltage switches, cables, wires, and weld seams. It follows national standards GB763, GB50150 and DL/T596, and complies with DL/T967-2005, IEC 62271 and other power testing regulations.
This instrument adopts the four-wire testing principle, with a measurement range of 0 - 20000.0 μΩ (100A range), a resolution of 0.1 μΩ, and an accuracy of 0.5% ± 2 digits. It has an internal microprocessor for automatic testing, is equipped with a seven-inch touch screen, a thermal printer and a 1000 data storage function, and supports RS232/USB interface transmission. Some models are designed as handheld, with a working temperature range of -25°C to 50°C, IP65 protection level and military-grade electromagnetic shielding technology. Through intelligent temperature control and triple protection mechanisms, it ensures stable operation in humid and highly interfered environments, meeting the professional needs of power departments for on-site high-voltage switch maintenance and loop resistance testing in high-voltage switch factories.
The contact circuit resistance tester is designed by combining digital circuit technology and switching power supply technology. It is suitable for measuring the contact resistance and circuit resistance of switch control equipment. The test current adopts the recommended direct current of 100A/200A by national standards. It can directly measure the circuit resistance and contact resistance under a current of 100A/200A, and display the results digitally. This instrument is accurate in measurement and stable in performance, and is suitable for on-site high-voltage switch maintenance and circuit resistance testing in high-voltage switch factories by power and power supply departments.
The resistance of the conductive circuit of a high-voltage circuit breaker mainly depends on the contact resistance between the moving and static contacts of the circuit breaker. The existence of contact resistance increases the loss of the conductor when it is energized, causing the temperature at the contact point to rise. The value of this resistance directly affects the current-carrying capacity during normal operation and, to a certain extent, the ability to cut off short-circuit current. Therefore, the value of the contact resistance of each phase of the conductive contact circuit of the circuit breaker is an important data for the installation, maintenance, and quality acceptance of the circuit breaker.
Product significance
At present, in the power system, the conventional QJ44 type double-arm DC bridge is widely used to measure the DC resistance of transformer coils and the circuit resistance of high-voltage circuit breakers. However, the test current of such bridges is only in the mA range, which makes it difficult to detect the defect of reduced conductor cross-sectional area in the conductive circuit of the transformer coil. When measuring the circuit resistance of the conductive circuit of the high-voltage switch, due to the influence of oil film and the oxide layer between the moving and static contacts, the measured resistance value is several times larger than the actual circuit resistance value, masking the true circuit resistance value. Therefore, the new version of the "Electrical Equipment Preventive Test Regulations" stipulates that the measurement current for the circuit resistance of circuit breakers and disconnectors should be no less than 100A to ensure the accuracy of the measurement.
National standards GB763, GB50150 and power industry standards DL/T596 all stipulate the measurement of the circuit resistance of the conductive circuit of circuit breakers: it should be measured by the DC voltage drop method, with the current not less than 100A. The resistance of the conductive circuit of the circuit breaker mainly depends on the contact resistance between the moving and static contacts of the circuit breaker. The existence of contact resistance increases the loss of the conductor when it is energized, causing the temperature at the contact point to rise. The value of the resistance directly affects the current-carrying capacity during normal operation and to a certain extent, the ability to cut off short-circuit current. Therefore, the resistance value of each phase of the conductive circuit of the circuit breaker is an important data for the installation, maintenance and quality acceptance of the circuit breaker.
Contact circuit resistance tester: Contact resistance tester, switch circuit resistance tester, circuit resistance tester, contact (circuit) resistance tester
Types and Uses
Loop Resistance Tester: Purpose and Application Scope of Ground Resistance Meter: The ground resistance meter is used for directly measuring the ground resistance values of various grounding devices, and it can also be used for general low-resistance measurements. The four-terminal button (0 - 1 - 10 - 100 Ω specifications) can also measure the soil resistivity.
Loop Resistance Tester: Single-Clamp Loop Resistance Tester
The performance and features of the single-clamp loop grounding resistance tester: The unique single-clamp design can avoid the error caused by mutual interference between the two probes of the double-clamp type. No need to dig auxiliary ground stakes, just clamp it directly to measure.
Loop Resistance Tester: Universal Ground/Insulation Resistance Tester
There are many testing methods: double-clamp grounding resistance test, four-pole grounding resistance test, soil resistivity test, insulation resistance test, AC/DC resistance tester voltage test, current RMS value test.
Loop Resistance Tester: Grounding Impedance Tester
When using the clamp-type grounding resistance meter series for measurement, no auxiliary grounding rods are required, and the grounding of the device under test does not need to be interrupted. Just clamp the grounding wire or rod, and the ground resistance to ground can be measured up to 0.1 Ω. It can also measure the current.
Loop Resistance Tester: Loop Resistance Tester
Microprocessor control, with high precision and high reliability. Three indicator lights check if the wiring is correct. Direct short-circuit protection current and grounding fault current are displayed. It will automatically lock when the test resistance overheats.
Loop Resistance Tester: Digital Type Ground Resistance Tester
This tester is specifically used to measure the ground resistance values of various grounding devices such as electrical equipment and lightning rods. The product is an all-electronic instrument. The key circuit is assembled from integrated circuits produced by Texas Instruments in the United States. The testing principle is advanced.
Loop Resistance Tester: Double-Pin Clamp Ground Resistance Tester
It has multiple grounding resistance measurement methods: without auxiliary pole / three-pole / four-pole / multiple pole method suitable for various measurement environments * Wide measurement range: 0.002 Ω - 300 KΩ to meet various requirements.
Technical Specifications
Measurement range: 100A - 0 - 3000uΩ
200A - 0 - 1500uΩ
Measurement accuracy: 0.5 grade
Display method: Liquid crystal display. Result printing.
Operating voltage: AC 220V
Working principle: Sampling - Amplification - Holding - A/D conversion - Single-chip microcomputer processing -
Output result: Display and printing
Form structure: Adopting standard chassis structure, compact. Power input socket and power switch are located at the bottom of the instrument.
| Specification | Precision | Measurement range | Explanation |
| GHHL-100 | 0.5 grade ± 1 unit | 1～1999μΩ | Manual 100A type |
| GHHL-100A | 0～3999.9μΩ | Intelligent 100A Model | |
| GHHL-200 | 1～1999μΩ | Manual 200A type | |
| GHHL-200A | 0～3999.9μΩ | Intelligent 200A Model |
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