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Chapter 4 Measurement

 

 

21 

 

4.3 Before Measurement

 

 

This section describes notes on accuracy and the handling of the Rogowski 
Coil Sensor part when measuring the current using this instrument.   

4.3.1 To Achieve Accurate Measurement

 

As explained in Chapter 3 “Measurement Principle,” the Rogowski Coil is a 
wire rod wound tight around a tube-like wick material, as illustrated in Figure 
3.1.  The  coil  formed  into  a  ring  body  detects  a  change  in  magnetic  flux 
caused  by  the  current  passing  through  the  inside  of  the  coil.  The  evenly 
wound coil causes no error even when the current to be measured does not 
flow through the center of the coil. In addition, each  turn of coil enables the 
cancellation of external magnetic fields.   
Note  that  the  uniformity  of  the  Rogowski  Coil  is  slightly  disturbed  at  the 
Rogowski  Coil  connection  part  on  the  joint  hole,  which  is  designed  to 
maintain  the  coil  as  a  ring  body.  The  area  around  this  part  is  not  suited  to 
measure  current.  In  addition,  the  coil  cannot  sufficiently  cancel  a  magnetic 
field produced by external current flowing through in the vicinity of this part.   
This  instrument  is  calibrated by  current  that  flows  through the  center  of  the 
Rogowski  Coil.  Avoid  measuring  current  in  the  vicinity  of  the  joint  hole  as 
much  as  possible  in  order  to  achieve  accurate  measurement.  It  is 
recommended to measure current at the center of the Rogowski Coil.   
For  reference,  Figure  4.3  shows  the  position  of  the  connection  part  of  the 
Rogowski Coil. 

 
 

 

 

 
 
 

 

 

The connection part of the Rogowski Coil is in the center of the dotted circle. 
It  is  known  that  a  larger  measurement  error  is  caused  as  the  current  to  be 
measured  comes  closer  to  this  part.  Avoid  measuring  current  in  the  dotted 
area, because a measurement error of 

−4% or more may be caused by the 

measurement performed  in  the  area.  In  addition,  the  coil cannot  sufficiently 
cancel  the  magnetic  flux  produced  by  external  current.  Before  measuring 
current, place conductors in which current flows other than the conductor  to 
be  measured  away  from  the  Rogowski  Coil  connection  part  as  much  as 
possible.   

 

Figure 4.3    Rogowski Coil Connection Part

 

Содержание SS-293L

Страница 1: ...Rogowski Coil Current Probe SS 293S 293L 294S 294L SS 295S 295L 296S 296L Instruction Manual...

Страница 2: ...2015 IWATSU TEST INSTRUMENTS CORPORATION All rights reserved...

Страница 3: ...w 9 1 2 Features 10 1 3 Usage Example 11 Chapter 2 Names and Functions of Parts 12 2 1 Main Unit 12 2 2 Names and Functions of Parts of Main Unit 13 2 3 Rogowski Coil Sensor Part 14 Chapter 3 Measurem...

Страница 4: ...Memo...

Страница 5: ...efinition of Warning and Caution as used in this manual Warning Incorrect operation or failure to observe a warning may result in death or serious injury Caution Incorrect operation or failure to obse...

Страница 6: ...ble of this instrument s input part for the measurement where voltage exceeds the following value the voltage is described on the input part of this instrument An electric shock or failure may occur 1...

Страница 7: ...ollowing when handling the coil sensor cable or BNC cable of this instrument If not an electric shock fire or failure may occur Do not use any of the cables if damaged Contact Iwatsu office or our sal...

Страница 8: ...n off the power to this instrument After that contact Iwatsu office or our sales distributors for repair When thunder begins pull out the power plug of a device to which this instrument is connected f...

Страница 9: ...orage temperature 10 to 60 C no dew condensation Storage humidity 80 RH or less Do not place this instrument in a location with excessive humidity or dust If not an electric shock fire or failure may...

Страница 10: ...batteries in this instrument A reversely placed battery will result in battery explosion or leakage This may cause a fire injury failure or contamination of the surrounding environment Do not throw us...

Страница 11: ...s If there is a missing item or an item damaged during transportation immediately contact Iwatsu office or our sales distributors Components Main unit 1 Accessories See the accessories table below Acc...

Страница 12: ...tal hydride and nickel cadmium Request a recycling company in accordance with local laws or regulations Repair and sending instrument to be repaired If a failure occurs send the instrument to Iwatsu o...

Страница 13: ...an electromotive force in the coil The electromotive force is proportional to a differential value of the current The output electromotive force of the Rogowski Coil is the differential waveform of t...

Страница 14: ...oil is 8 5 mm designed to detect current has the following advantages Wide applications of measurement are possible in any place Superior heat resistance and insulation property around the coil This i...

Страница 15: ...a sensitivity mV A set for each main unit The converted voltage is output from the output terminal of the main unit Inputting the output voltage to an oscilloscope and other monitoring devices allows...

Страница 16: ...Chapter 2 Names and Functions of Parts 12 Chapter 2 Names and Functions of Parts 2 1 Main Unit...

Страница 17: ...zero point adjustment on the side of ZERO ADJ Insert the accessory screw driver into the hole to perform zero point adjustment Section 4 2 Input part The sensor cable refer to Section 2 3 integral wit...

Страница 18: ...closed loop There is a screw lock and joint hole to secure the other end of the coil Joint hole A part of the joint box and has a hole to insert the Rogowski Coil and a screw lock to lock and release...

Страница 19: ...rent current waveform in conductors to be measured It consists of the Rogowski Coil Sensor part and the main unit integrator Sections 3 1 and 3 2 in this chapter describe measurement principles and fu...

Страница 20: ...aw The magnetic field changes with time because alternating current flows in the conductor to be measured In the Rogowski Coil magnetic flux changes along the loop When it changes an electromotive for...

Страница 21: ...he output voltage of the main unit current waveform is observed by an oscilloscope and other monitoring devices through the BNC cable As expressed by the following Equation 3 3 the voltage component V...

Страница 22: ...ies in the battery case Note Do not place them in the wrong orientation c Close the lid of the battery case 3 Connect the accessory BNC cable to this instrument a Connect one end of the BNC cable to t...

Страница 23: ...se the lock of the Rogowski Coil be sure to turn the screw lock in a direction opposite the direction indicated by LOCK until you feel a click After releasing the lock remove the one end of the Rogows...

Страница 24: ...to the O side 5 Adjust the zero point of the output observed by monitoring devices a Have the accessory screw driver ready b As shown in the figure below there is a hole for zero point adjustment on t...

Страница 25: ...t In addition the coil cannot sufficiently cancel a magnetic field produced by external current flowing through in the vicinity of this part This instrument is calibrated by current that flows through...

Страница 26: ...section of the sensor cable where the resisting voltage is not guaranteed away from high voltage parts 4 3 3 To Minimize Influence of Fluctuations in Voltage If there is a part whose voltage fluctuat...

Страница 27: ...OCK until you feel a click Warning Avoid the generation of corona discharge in an environment where high voltage is applied to the sensor part for a long time Depending on the frequency of the applied...

Страница 28: ...error of 250 ppm C when the temperature is 10 C or less or 70 C or more Output Maximum voltage range 6 V load 100 k Connector BNC Linearity 0 05 of full scale Zero point adjustment range 300 mV or mor...

Страница 29: ...2 Operation time of this instrument during the use of batteries The continuous operation time of this instrument is about 30 hours when alkaline batteries are used The LOW BATTERY LED lamp lights up w...

Страница 30: ...Chapter 5 Specifications 26 5 2 Appearance 1 Main Unit Unit mm...

Страница 31: ...Chapter 5 Specifications 27 2 Rogowski Coil Sensor Part Unit mm...

Страница 32: ...Chapter 5 Specifications 28 Memo...

Страница 33: ...Address 7 41 Kugayama 1 Chome Suginami ku Tokyo 168 8511 Japan Phone 81 3 5370 5483 Facsimile 81 3 5370 5492 URL http www iti iwatsu co jp E mail info iti iwatsu co jp...

Страница 34: ...SS 293S 293L 294S 294L 295S 295L 296S 296L...

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