PDR302
EARTH RESISTANCE METER
INSTRUCTION MANUAL
CONTENTS
[1] Warning Instruction for safe use
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15
[2] INTRODUCTION
………………………………………………
16
[3] PANEL ARRANGEMENT AND ACCESSORIES
…………
17
[4] OPERATION
……………………………………………………
18
1. Arrangement of Auxiliary Earth Bars and Connections
…
18
2. Measurement of Earth Resistance Using the Tripolar
System
………………………………………………………
19
3. Measurement of Earth Resistance Using the Bipolar
System
………………………………………………………
19
4. Measurement of Leakage Voltage Using the ACV
………
20
5. Replacing the Batteries
……………………………………
20
6. Maintenance
…………………………………………………
21
[5] SPECIFICATIONS
……………………………………………
22
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1
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[1] Warning Instruction for safe use
(80 %
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15
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[2] INTRODUCTION
1.5 V
30 V
The Sanwa PDR302 Earth Resistance Meter is just the device to
satisfy these requirements as it features solid-state circuitry and
automatic direct reading of earth resistance using a battery-
powered constant-current system. Some of the main benefits and
advantages of the PDR302 include:
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[3] PANEL ARRANGEMENT AND ACCESSORIES
1 Meter (indicator)
2 Pointer
3 Zero adjuster
4 Earth resistance scale
(010 Ω ), black
5 AC voltage scale
(030 V ), red
6 Range switch
7 Earth resistance
measurement switch
(push-button)
8 Power supply
indicator/battery check
9 E terminal (for grounding)
10 P
(S)
terminal (for auxiliary grounding)
11 C
(H)
terminal (for auxiliary grounding)
12 Panel
13 Rear case
14
E-terminal connection cord (black),
approx. 5 m, with alligator clip (black)
15 P
(S)
terminal connection cord (blue),
approx. 10 m, with alligator clip (blue)
16 C
(H)
terminal connection cord (red),
approx. 20 m, with alligator clip (red)
17 Lead wire reel, x 3
18 Earth bars (metal), 2 pcs.
19 Auxiliary grounding value excess
indicator lamp
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10
m
10
m
P C
[4] OPERATION
1. Arrangement of Auxiliary Earth Bars and Connections
As shown in Figs.1 and 2, the auxiliary bars are arranged parallel
to the earth (E) at intervals of 510 meters. Where it is impossible
to align them parallel, a certain amount of bending (E , P
(S) C(H)
120 ) is allowed.
When the nets are used instead of the bars, the R
P(RS) and
R
C(RH)at the earth poles read larger. Normally, the impedance of
the power supplying constant AC current to E-C
(H) is high enough
to prevent reading errors due to a slight increase of resistance.
However, when the nets are used on a concrete surface, wet them
to enable better contact with the ground. Measurement is not
possible on asphalt surfaces. Once the bars have properly set,
make connections as illustrated.
Take extra care not to drop the earth bars or pierce anything
with them when carrying them or inserting them into the
ground. The tips of the earth bars are very sharp.
WARNING
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2.
Measurement of Earth Resistance Using the Tripolar System
CAUTION:
Make sure the earth bars are inserted into the ground securely. If they are
improperly inserted, R
P
(R
S
) and R
C
(R
H
) values increase. This will result in
errors in measurement values and instabilities in indicated values.
1. The range switch is placed at one of the three ranges to be selected
according to the size of the earth resistance (R
E
).
2. Press the MEASURE PUSH switch. The power indicator lamp (ON) will
light red and the pointer will point at the earth resistance value (R
E
).
3. For the “X1” range, the figures along the arc are read directly (010
Ω). For the “X10” and “X100” ranges, they are read multiplied by 10 for
0100 Ω and by 100 for 01000 Ω.
4. If the red LED (OVER AUX. R) on the upper left of the meter scale
lights after the MEASURE PUSH switch is pressed, this means the
auxiliary grounding resistance value is excessive and correct
measurement cannot be performed. Should this happen, re-insert the
earth bars into the ground.
5. If the power indicator lamp (ON) starts blinking after the MEASURE
PUSH switch is pressed, this means the batteries are low. Replace
them with new ones. For details, refer to “5. Replacing the Batteries.”
3.
Measurement of Earth Resistance Using the Bipolar System
1. When earth is available whose resistance value has been already
detected or whose resistance is extremely low and can be regarded
as immaterial with respect to the earth resistance in question, you can
measure unknown earth resistance by taking advantage of the
electrical circuit ground at hand.
2. The earth of unknown resistance is connected to the terminal E.
Next, insert the plugs of the C-terminal connection cord to the P
(S)
and
C
(H)
terminals and connect the alligator clip to a point with known earth
resistance value.
3. The value measured with this method is the sum of an unknown
earth resistance R
X
and known earth resistance rE. If the value is
already known, obtain the true value by subtracting the known earth
resistance value rE from the meter reading RE.
Make sure that the object being measured — an electric appliance, for
example — is properly grounded. If the object is improperly grounded or
not grounded, commercial voltage may leak into or be applied to the
object. Double-check all safety precautions before starting measurement.
WARNING
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4. Measurement of Leakage Voltage Using the ACV
1. Once connections have been made, turn the range switch “ACV.”
2. The pointer responds if there is any earth voltage present to indicate
leakage AC current flowing into the earth circuit. The red 030 V
scale reads it.
3. If the scale reads above 5 V, there will be interference with earth
resistance measurement. In this case, before taking measurement,
open either the power circuit, the equipment using the earth, or its
earth circuit to reduce the effect of the voltage leak.
4. Earth voltage can be checked independently across E and P
(S)
without using the C
(H)
terminal.
5. Replacing the Batteries
1. When the batteries are low, the power indicator lamp (ON) starts
blinking after the MEASURE PUSH switch is pressed. When this
happens, replace the batteries with new ones. Refer to Fig.4 for
replacing the batteries.
1. Never attempt to supply voltage over 30 V — the maximum
allowable voltage — since the ACV of this unit uses leakage
AC voltage (ground voltage).
2. Never supply standard commercial voltage (AC 100 V for
example).
E
P C
Rx
rE
Earth resistance to be measured: Rx
Rx = R
E – rE
Connect to a point with known earth resistance
Meter reading RE
C
(H)
terminal connection cord (red)
Fig.3
WARNINGS
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20
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3 mm
4
2. Unfasten the screw from the battery compartment cover on the
back of the unit. While pressing the rectangular protrusion in
the center of the cover as shown in Fig.4 , slide it down to
remove it. Insert new batteries and align them according to the
battery directions shown in Fig.4 .
3. When the new batteries are loaded, replace the cover on the
battery compartment and tighten the screw to secure it.
CAUTIONS
1. Be sure to use specified batteries only. Never mix different
types or brands of batteries even if the rated voltage is the
same.
2. To avoid deterioration of performance, use only brand-new
batteries when replacing batteries.
6. Maintenance
1. Remove the batteries when not using the tester for extended
periods.
2. Do not drop the instrument or otherwise subject it to severe
shock. Do not expose it to high temperatures or moisture.
3. The indicator cover is treated with anti-electrification coating. Do
not rub it hard with a dry cloth. If the coating is found ineffective,
you can spray it with disc cleaner as a temporary measure.
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[5] SPECIFICATIONS
1. Measurement Ranges
Ω(earth resistance):
X1 reading 0 10 Ω(0.2 Ω per scale)
X10 reading 0 100 Ω(2 Ω per scale)
X100 reading 0 1,000 Ω(20 Ω per scale)
ACV (leakage voltage) 0 30 V(1 V per scale)
2. Accuracy
±5 % fs for Ω x 1
±2.5 % fs for Ω x 10, Ω x 100
±2.5 % fs for ACV
3. Batteries
R6(SUM-3)x6
4. Method of Measurement
Constant-current system (tripolar & bipolar)
5. Constant Current AC Power
Abt. 100 V(1 kHz), through inverter
6.
Auxiliary grounding value alarm LED lights at approx.10 kΩ or more
7. Battery Alarm
Blinking LED, approx. 6.5 V operation voltage
(LED normally lights during measurement)
8. Accuracy Guarantee Temperature/Humidity Range
15 35 , 80 % RH or less
No dew condensation allowed
9. Operating Temperature/Humidity Range
0 40 , 80 % RH or less
No dew condensation allowed
10. Accessories
Measurement cords:
1 ea., black 5 m / blue 10 m / red 20 m
3 lead wire spools
Alligator clips: 1 ea., black / blue / red (CL-302)
Earth bars: 2 ea. (CL-ER)
Carrying case: 1 (C-PDR302)
Storage bag: 1 (C-302CB)
Instruction manual: 1
11. Dimension and Mass
175 x 118 x 55 mm, Abt. 500 g(main unit)
] TL-66
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This warranty is valid only within Japan.
PDR302
SANWA ELECTRIC INSTRUMENT CO.,LTD.
Dempa Bldg,Sotokanda2-Chome Chiyoda-Ku,Tokyo,Japan
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