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MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester
MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester
MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester
MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester
MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester
MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester

MEWOI3900C Wireless Online Earth Resistance Tester,Ground resistance tester,GEO Earth Tester

2023-07-22 14:08:26  

Wireless Online Earth Resistance Tester

  • Main Features : 1. Online monitoring of grounding resistance, grounding voltage. 2. Ground resistance :0.01Ω~2000Ω 3. Communication method :RS485 or GPRS 4.Monitoring Interval Time :Setting range of automatic monitoring interval time :1-999 h 5. Measurement rate:over 10000 times 6. LCD Size :128mm×75mm
  • Serial No. :
Contact Us For QuotationEmail:  464560351@qq.comWhatsapp&Wechat:+8618620373879

INTRODUCTION

MEWOI3900C Earth Resistance Online Detector is high-tech product that our company has devoted to "grounding resistance detection technology research" for more than ten years, Using precision 3-wire or simple 2-wire measurement method to test the grounding resistance. Adopt average value rectification method to test grounding voltage, online detection, real-time monitoring. User can select RS232 or RS485 communication, according the protocol MODBUS to secondary development, build network, realize remote multipoint online monitoring etc.

MEWOI3900C Earth Resistance Online Detector displayed by super large LCD, very clear and obvious. The alarm critical value can be set via the button, and with the sound and light alarm indication. Ensure the high accuracy, high stability and high reliability of real-time online monitoring of grounding resistance value in various place.

MEWOI3900C Earth Resistance Online Detector Tester suitable for transmission line tower grounding, underground mine equipment grounding , weather lightning protection grounding, petrochemical grounding ,communication base station grounding, power substation grounding , railway grounding , building warehouse grounding , electrical equipment grounding, etc.


MEWOI3900C  Accessories

 Detector

  ● 9P wiring terminal

  ● Warranty card/Qualification card

  ● Paper Box

 

SPECIFICATION

Measurement Range & Accurancy

Measurement Function

Range

Accuracy

Resolution

Earth Resistance

0.01Ω~20Ω

±2%rdg±3dgt (auxiliary earth resistance 100Ω±5%,Voltage to earth<10V)

0.01Ω

0.1Ω~200Ω

±2%rdg±3dgt (auxiliary earth resistance 100Ω±5%,Voltage to earth<10V)

0.1Ω

1Ω~2000Ω

±2%rdg±3dgt (auxiliary earth resistance 100Ω±5%,Voltage to earth<10V)

Earth Voltage

0~600V AC

±2%rdg±3dgt

1V

(Note: 23℃±5℃,below 75%rh)


Technical Parameter

Function

Description

Measure Mode

Precise 3-wire measurement ,simple 2-wire measurement

Measure Method

Ground resistance:rated current change-pole method,measured current11mA Max,128Hz;

  voltage to ground: average value ectification method. 

Power Supply

Standard:12V±1VDC、400mA Max(provided externally)

Weight

Detector:380g

Dimension

130mm×90mm×54mm

LCD Size

47mm×28.5mm

Measurement Time

Voltage to ground:about 2 times/second ; ground resistance : about 30 seconds/time

Measurement Rate

Over 10000  times

Monitoring Interval  Time

Setting range of automatic monitoring interval time :1-999 h

Instrument Interface

Pluggable  terminal blocks: 9 pin connector

Communication  Method

RS485 or GPRS

Data Storage

99 groups,flash display “99”  symbol indicate storage is full

Data Access

Data read function :“READ” symbol display

Overflow Display

Exceed measurement range overflow function :”OL” symbol display

Alarm

Audible and visible alarm

Power Supply Voltage

When power supply voltage decreases to about 10V , power supply low symbol will display, and remind to replace  the power.

Overload Protection

Measurement ground resistance: E-P, E-C between each interfaces AC 280V/3 seconds

Electromagnetism

IEC61010-4-3,Wireless frequency electromagnetic field≤1V / m

Line Voltage

Measuring the voltage to ground: Below AC 600V

Accessories

Detector: 1PCS; GPRS Communication module+external antenna:1set(optinal),9P terminal block


Network Structure



  • Wireless Network System (Self -Development Software)

Wireless network system through GPRS communication protocol to transmit data ,build up by the detector(built-in GPRS transceiver module), 【SIM communication card, monitoring software, power adapter, computer(above equipment need the user provide and secondary development)】 and other components for long-distance ground resistance monitoring., distance is not limited.




Principle & Application

  • Measurement Principle


1.Earth voltage measurement adopts average value rectification method. 

2.Earth resistance measurement adopts rated current change-pole method.

That is, the AC rated current I (11mA Max,128Hz) flows between the measuring

object E (ground electrode) and the C (current electrode); Get the potential difference

V between the E and the P (voltage electrode), and then get the grounding resistance

value Rx according to the formula: R=V/I.

3.The working error (B) is the error obtained within the rated working conditions, which is calculated from the inherent error (A) and variation error (Ei).


       A: Intrinsic error                                                     E1: Variation due to position change 

E2:Variation due to power supply voltage change       E3:Variation due to temperature change     

E4:Variation due to interference voltage change            E5:Variation due to contact electrode resistance change

E7: Variation due to system frequency change              E8:  Variation due to system voltage change


  • Wiring Connection & Measurement Method



1.First: the user needs to make auxiliary grounding poles P and C every 5 ~ 10 meters on the same straight line near the monitored grounding pole E. Auxiliary grounding pole should adopt grounding materials or stainless steel material, prevent rust and rot, the grounding resistance value as small as possible, the general grounding resistance requirements no more than 100 Ω, ground voltage is less than 10V, so as to ensure the accuracy of the on-line monitoring.

Secondly: according follow table to connect the detector, computer, power supply, etc. It`s better that the connection between the detector and the auxiliary earth pole secured by electric power wire (for later maintenance and disassembly), or by welding.




2.The grounding resistance on-line monitoring usually adopts the precise three-wire method, but also can use the simple two-wire method to test. The simple two-wire method is used to measure the grounding resistance by using the existing grounding electrode which grounding resistance value is smaller as the auxiliary grounding electrode and short-connecting the C and P interfaces. Auxiliary grounding rods C and P can be instead by metal water pipes, fire hydrants and others metal embedded objects, common grounding of commercial power systems or lightning protection grounding poles of buildings, etc. During measuring, pay attention to removing the oxide layer at the connection point of the selected metal auxiliary grounding body. Simple two wires method wiring connection as right side figure:

The simple method measure the grounding resistance, the tester reading is the sum of the grounding resistance of the grounded body to be measured and the grounding resistance of the commercial grounding body.

R=RX+re


Which: R --- The tester reading value;

RX ---The grounding resistance value of measured grounding object;

re--- the grounding resistance value of a common grounding body such as a commercial power system.

Then, the earth ground resistance value of measured grounding body is:

RX=R-re

Use simple method to measure the grounding resistance, try best to select the grounding body with a smaller re value as the auxiliary grounding electrode, so that the detector reading is closer to the real value.


Related Series Model

ModelRangeLCD SizeDifference
MEWOI3900

0.01Ω~2000Ω

0-600V AC

128mm×75mmCan build the Wired Network System
MEWOI3900C 0.01Ω~2000Ω

0-600V AC

47mm×28.5mmCan build the Wired Network System and Wireless Network System


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