ZWS490 Digital Earth Resistance Tester

  • Strong anti-interference ability
  • Good consistency in repeated testing

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:
Selection method:
Double clamp method:
Double clamp method:
Soil resistivity:
10Ωm(10.00kΩm ~99.99kΩm)
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±3dgt (300Ω~3000Ω)
Double clamp grounding resistance:
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).


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