Company Profile
The company specializes in the research anddevelopment, production, sales, and service of electric power system automation testing equipment, providing customers with one-stop services.
Product Introduction
ZWS490 double clamp earth resistance tester is specially designed and manufactured for ground resistance, soil resistivity,ground voltage, grounding lines leakage current, AC and DC resistance in combination with the new lightning-proof ground resistance testing standard. The testing current reaches 20mA. Comply with digital and micro-processing technology,precision 4-wire method, 3-wire method and simple 2-wire, selection method, and double clamps method are used to measure vast ground resistance, inputting FFT (Fast Fourier Transform) technology, AFC (Automatic Frequency Control) technology, with a unique function of anti-interference capability and the ability to adapt to the environment, consistency of repeat testing, to ensure high precision, high stability and reliability for prolonged measure, which is widely used in electric power, telecommunications, mete orology, oil field,construction, lightning protection, industrial electrical equipment and other earth resistance, soil resistivity, earth voltage, AC voltage measurement.
Functional Characteristics
ZWS490 Earth Resistance Tester also named: double clamp Earth Resistance Tester, double clamp grounding resistance Tester,The tester is composed of host machine, current clamps(2pcs), data software, test line, auxiliary grounding rod,communication line and so on. The special toolbox design of the main engine uses polypropylene plastics as raw materials and adds a new type of composite filler for one-time injection molding. It has the advantages of low density, strength, stiffness,hardness, abrasion resistance, heat resistance and insulation. The box can withstand about 200 kg of pressure to ensure high precision,high stability and high practicability of various environmental tests. The host of large LCD display with backlight, bar graph indicating that can be seen clearly, it can store 2000 sets of data. Through data software, it can realize the functions of reading, consulting,saving, reporting and printing historical data.
Technical Parameter
| Size |
ZWS490 |
| Function |
Grounding resistance, soil resistivity, DC resistance, conduction resistance and equipotential connection resistance test, grounding AC voltage test, AC test, leakage AC test. |
| Power |
DC 9V(Zi-Mn dry battery R14S 1.5V 6 PCS, continuous standby for 300 hours ) |
| Back light |
Controllable white screen backlight, suitable for use in dark field. |
| Testing method |
precision 234 wire method test grounding resistance, selection method, double clamp to measure grounding resistance |
| Measure method |
234 wires testing method: Pole-changing method, short circuit testing current 20mA Max. |
| Selection method: Pole-changing method, short circuit testing current 20mA Max. |
| Double clamp method: non-contact type transformer, testing current 1mA Max. |
| Soil resistivity: quadrupole method (Winner method) |
| DC Resistance: Pole Changing Method |
| AC Current: Average Rectifier (Clamp) |
| Ground Voltage: Average Rectifier (P(S)-ES Interface) |
| Range |
Measuring grounding resistance (Re) and DC resistance by two, three and four-wire method: 0.000~30000Ω
Selective Method for Measuring Grounding Resistance (Re):0.00~3000
Measurement of Grounding Resistance (Re):0.01Ω~200Ωby Double-clamp Method
Soil resistivity (p): 0.00Ωm-9000 kΩm
Grounding Voltage (50Hz/60Hz): AC 0.0-100.0V
AC Current (50Hz/60Hz): AC 0.00mA-600.0A |
| Max. resolution |
Measuring grounding resistance (Re) and DC resistance by 234 method:
0.001Ω（0.000Ω～29.999Ω）
0.01Ω（30.00Ω～299.99Ω）
0.1Ω（300.0Ω～2999.9Ω）
1Ω（3000Ω～30000Ω） |
Selection method:
0.01Ω（0.00Ω～29.99Ω）
0.1Ω（30.0Ω～299.9Ω）
1Ω（300Ω～3000Ω） |
Double clamp method:
0.01Ω（0.01Ω～0.99Ω）
0.1Ω（1.0Ω～29.9Ω）
1Ω（30Ω～200Ω） |
Double clamp method:
0.01Ω（0.01Ω～0.99Ω）
0.1Ω（1.0Ω～29.9Ω）
1Ω（30Ω～200Ω） |
Soil resistivity:
0.01Ωm（0.00Ωm～99.99Ωm）
0.1Ωm（100.0Ωm～999.9Ωm）
1Ωm（1000Ωm～9999Ωm）
10Ωm（10.00kΩm ～99.99kΩm）
100Ωm（100.0kΩm～999.9kΩm）
1kΩm（1000kΩm～9000kΩm）Grounding voltage(50Hz/60Hz): 0.1V AC(50Hz/60Hz): 0.01mA |
| Accuracy |
234 wire method for measuring ground resistance (R) DC Resistance：
±2%rdg±0.05Ω （0.000Ω～29.999Ω）
±2%rdg±3dgt （30.00Ω～299.99Ω）
±2%rdg±3dgt （300.0Ω～2999.9Ω）
±4%rdg±3dgt （3.000kΩ～30.00kΩ）
Note: 1. Additional error of rC Max or rP Max is <5% rdg+5 dgt.
(rC max: 4K + 100R < 50k, rP max: 4K + 100R < 50k)
2. The additional error and 5 V interference voltage is <5%rdg+5 dgt. |
Selection method(Re)：
±2%rdg±5dgt（0.00Ω～29.99Ω）
±2%rdg±3dgt（30.0Ω～299.9Ω）
±2%rdg±3dgt （300Ω～3000Ω） |
Double clamp grounding resistance：
±10%rdg±5dgt（0.01Ω～100Ω）
±20%rdg±5dgt（101Ω～200Ω） |
Soil resistivity(ρ): according to the accuracy
（ρ=2πaR a:1 m～100m；π=3.14）
Grounding voltage （50Hz/60Hz）： ±2%rdg±3dgt
AC （50Hz/60Hz）： ±2%rdg±3dgt |
| Testing voltage wave shape |
sine wave |
| Testing frequency |
128Hz/111Hz/105Hz/94Hz(Automatic frequency selection) |
| Short circuit test current |
AC 20mA max |
| Open circuit test voltage |
AC 40V max |
| Electrode spacing |
1m～100m |
| Test time |
AC: approx 2times/sec;
Ground voltage：approx 2times/sec；
ground resistance：approx 7times/sec； |
| Test times |
5000times above ( short circuit test, test 1 time,Stop for 30 seconds and retest. ) |
| Circuit voltage |
AC 100V below test |
| Auxiliary grounding test |
Able to measure auxiliary earth resistance, 0.00KΩ-30000Ω(100R+rC<50kΩ, 100R+rP<50kΩ) |
| Alarm function |
When measuring value exceeds alarm setting value, there is “DU-DU-DU” alarm remind |
| Electromagnetic features |
IEC61326(EMC) |
| Protection type |
IEC61010-1(CAT Ⅲ 300V、CAT IV 150V、pollution class2)；
IEC61010-031；IEC61557-1(ground resistance)；IEC61557-5(soil resistivity)；JJG 366-2004(ground resistance meter)l; JJG1054-2009(clamp grounding resistance). |
