Nilsson 400 PDF

 

SOLID

STATE

4-PIN SOIL RESISTANCE METER

 

SINCE 1919 

N

SSON   E L E C T R I C A L

LABORATORY,

IN

SPECIALISTS IN ELECTRONIC AND ELECTRICAL MEASUREMENTS

333 WEST SIDE AVENUE, JERSEY CITY, N.J.  07305 201 1   -521   -4863 TEL. (201 )-521 -4860 FAX.   20

 

 

NILSSO NILSS ON M ODE DEL L 40 4 0 0 4 - PI N S SO OI L RE RESISTANCE SISTANCE M ETER ETER

CONTENTS PAGE

DESCRIPTIONOF

DESCRIPTION . . . . . . . . . . . . . . . . . . . . 3 ~

OPERATING INSTRUCTIONS 4 Pin Method . . . . . . . . . . . . . . . . . . Soil Box . . . . . . . . . . . . . . . . . . . . . . 3 Pin Method . . . . . . . . . . . . . . . . . . 2Pin Method . . . . . . . . . . . . . . . . . . Single Probe Method . . . . . . . . . . . . . .

Soil Resistance Meter is The Nilsson  Mode14 a 4 terminal, null balancing ohmmeter. It measures resistance from .01 ohm to l l  megohms. The Model 400can   be used as a 4, 3, or 2 pin device for soil resistance measurements, or can be used with a soil box or a single probe. The unit generates a low voltage 97 Hz square

4 5 5 6 6

wave current whose between the is Cl connected and C2   binding posts. The detector, input between the PI and P2 binding posts is only sensitive to 97 Hz, and so is not affected by stray A.C.  or D.C.   currents. The detector senses the voltage drop between the and P2 binding posts, compares it to internal standard resistors, and indicates a difference on the null detector. When the null detector is balanced, using the range switch and the dial, the resistance in ohms between PI and P2 is the dial reading multiplied by the range switch position.

OPERATING NOTES . . . . . . . . . . . . . . . . 7 MAINTENANCE . . . . . . . . . . . . . . . . . . . 7

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MODEL400

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RECHARGEABLE12 VOLTBATTERYPACK   am P E R E H O U R S DESIGNED FOR USE WITH MODEL 715 PlPE&CABLE LOCATOR LS820 & 830CURRENT INTERRUPTERS into 12 VOLT BATTERY

any

110

A.C.

outlet 3

 

OPERATING INSTRUCTIONS 4 PIN METHOD When using the 4 pin method to measure soil resistance, the 4 pins should be driven into the ground in a straight line at the desired spacing. Good contact with the soil is important. The two “C” binding posts are connected to the two end pins, and the two “P” binding posts are connected to the adjacent center pins. (see fig. 1 )

position and note that the meter pointer moves to the right, indicating too high a setting. While holding the key in the “LOW” position step down thru the ranges until the pointer moves to the left of center. Then step back up one range and balance with the dial. For increased sensitivity and a finer balance, push the sensitivity key to the “HIGH” position and refine the balance. When a satisfactory balance has been achieved, multiply the indicated dial reading by the range switch setting to obtain the resistance in ohms. To calculate the resistivity   in ohms/cm apply the proper pin spacing multiplier factor or formula. (See table) S PACI NG EVEN FEET 1

FIG. 1 If the approximate resistance is not known, place the range switch at the “X1OOK” position and the dial at 10. Pull the sensitivity key to the “LOW” 4

2 3 4   10 15 20 25

MU LTIPLIER

191.5 . . . . . . . . . . . 383.0 . . . . . . . . . . . 574.5 .766.0 ::   : 957 5 . . . . . . . ...1915.0 . . . . . . . ...2872.5 . . . . . . . ...3830.0 . . . . . . . ...4787.5 . . . . . . . . . . .

S P A C I NG FEET–INCHES

MULTIP LI ER

2’7’’ . . . . . 5’3’’ . . . . . 7’10” . . . . 10’5” . . . . 13’1” . . . . 15’8” . . . . 18’3” . . . . 20’10” . . . 23’6” . . . .

. . . . . . . . .

. . ...500 . ...1000 . ...1500 . ...2000 . ...2500 . ...3000 . ...3500 . ...4000 . ...4500

ohms/cm =6.28XSXR (S in centimeters) all spaces equal ohms/cm spaces equal=191   .5XSXR (S in feet and tenths) all

 

 

 

Resistivity   in ohms/cm is average resistivity  of soil to a depth equal to the pin spacing (equal spacing

between pins). SOIL BOX For use with a soil box, attach the “C” binding posts to the end terminals of the box and the “P” binding posts to the adjacent center terminals. (see fig. 2)

 

I

3 PIN METHOD The three pin method can be used to measure the resistance to earth of a ground rod, ground bed, anode, etc. For this method, connect the “Cl” and “PI” binding posts to the object being measured using separate leads. (See Fig. 3). Connect “C2”  to a pin driven into the soil far enough away from the object under test so as not to influence the reading. 100 feet would be typical for a ground rod 15 to 20 feet deep. Connect “P2” to a pin 62% of the distance from the object being tested to the “C2”  pin. Balance and read in the usual way. A

TYPICAL

EXAMPLE

100’ h  

 

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1

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P2 PIN

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C2

 

PIN

OBJECT BEING TESTED

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FIG. 2 Balance and read in the usual way. Apply the correct multiplying factor, if any, for the box you are

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P2

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