EARTH HiTESTER 3143, 3151 Field measuring instruments Ground resistance meter Say goodbye auxiliary grounding rods with the 3143. Measure even on paved roads. 3-electrode measurement on the 3151 gives greater precision! Tangle-free 1 The 3143 requires no auxiliary grounding rods, making measurement easy. Presenting a next-generation ground resistance meter Grounding is increasingly important for the safe operation and maintenance of communications equipment and many other types of facilities. However, in an urban environment where the ground is covered with concrete or asphalt, conventional measurement methods that require inserting auxiliary grounding electrodes are difficult to use. The 3143 uses a new measurement principle that makes auxiliary grounding electrodes unnecessary, so it can be used to measure ground resistance on paved roads. Using the 3143 1. Wire as shown in the diagram. 2. Turn the rotary knob to measure. As the rotary knob is turned, the lowest resistance value that is displayed is the grounding resistance value. String along the ground (20m) Return Earth Rx Features ■Auxiliary grounding rods are unnecessary, greatly reducing time and effort. Measurement can be done easily on concrete or asphalt pavements. ■Measurements are easy to read. A large digital display shows measured values. ■Resistant to dirt. Dust resistance of parts such as the power switch and measurement dial has been increased and durability has been improved. Measurement Principle of the 3143 The 3143 obtains ground resistance Rx by measuring the loop impedance of the closed path that goes from the lead wire to earth, then back to a return line which is strung along the surface of the earth. The drawing below shows an equivalent circuit, where Rx is the ground resistance of the object being measured, C is the capacitance of the return wire relative to ground, and L is the inductance of the measurement cable. By varying the frequency of the measurement signal source so that LCR is serially resonant, the ground resistance Rx can be determined as follows. Rx = Vm / (Vc - Vm) × Ro Here, Vc is the signal source voltage, Vm is the voltage between the measurement terminals, and Ro is the signal source output resistance. With the 3143 you turn the measurement knob to vary the signal source frequency. As the knob is turned, the smallest value that appears (the value at the resonance point) is the ground resistance value Rx. Lead Wire Return Wire Ground being measured 3143 Equivalent Circuit Model Ground 3143 Equivalent Circuit At Resonance The 3143 is most appropriate for measuring the ground resistance of an individually grounded rod-shaped electrode. Convenient Features Bar graph display makes it easy to find measured resistance. Turn the rotary knob so that the graduations are centered. Dust-resistant switch Large, easy to read LCD display Easy-grip elastomer knob Differences from the Previous Instrument (Model 3151) Common ground resistance meters such as the 3151 measure the resistance using a frequency between 500 Hz and several kHz. The 3143 uses a frequency between 100 kHz and 1.5 MHz, close to that of a lightning surge. Therefore, measurement errors can result if the 3143 is used in situations such as the following. In these instances, we recommend using Model 3151. • Electrical grounding or mesh grounding. • Electrical power equipment grounding. • When the measurement point is located at a distance from the insertion point of the grounding electrode. 2 Count on The 3151 for Dependable Measurements The 3151 is a Standard Ground Resistance Meter Ground resistance measurement involves factors that are not encountered during ordinary resistance measurement, such as polarization of the earth, the influence of grounding current due to leak current and grounding voltage, and the influence of auxiliary grounding resistance. The 3151 is able to make more accurate measurements more safely under difficult conditions because it uses the alternating current potentiometer method to provide measurement accuracy, and because it contains features such as an auxiliary grounding resistance check feature and measurement frequency switching. Features ■ A ground resistance meter that meets EN standards Its safety and reliability know no borders. Use it anywhere with confidence. ■ Wide measurement range Take measurements to 115% of the measurement range. ■ More stable measurement Easily check the grounding condition of auxiliary grounding rods for better accuracy. Further, the measurement frequency switching lets you avoid influences such as that of high frequency grounding current. ■ Simple measurement feature Switch between "normal" and "simple" measurement modes with the press of a button. ■ Overvoltage protection and alarm feature If wires are incorrectly connected (as often happens during simple measurement of commercial power supplies), safety is provided by an alarm buzzer and overvoltage protection. ■ Resistant to dirt Parts such as the measurement switches and measurement dial have increased dust resistance and durability. ■ More convenient accessories A cable winder ensures freedom from cable tangles, and a convenient carrying case accommodates all measurement materials. Using the 3151 Normal Measurement (3 Electrode Method) 1.Wire as shown in the diagram. 2.Set the 2/3 electrode method switch to 3 electrode measurement. 3.Check for grounding voltage in the grounding voltage range. 4.Check the auxiliary grounding resistance values for C and P in the auxiliary grounding resistance range. 5.Measure using the appropriate resistance range. While pressing the measurement button, turn the resistance dial knob and read the resistance when the galvanometer reaches a balance. C E P E C Rx 5~10m 5~10m Simple Measurement (2 Electrode Method) 1.Wire as shown in the diagram. (Example of power supply grounding line connection) 2.Set the 2/3 electrode method switch to 2 electrode measurement. 3.Check for grounding voltage in the grounding voltage range. 4.Take measurements, choosing either ×10 or ×100. While pressing the measurement button, turn the resistance dial knob and read the resistance when the galvanometer reaches a balance. (Measured value = Rx + Ro.) AC 250 V max E Convenient Features P C Rx Ro 5M minimum Shock resistant taut band meter Overvoltage protection and alarm buzzer Prevents damage due to incorrect connection during simple measurement (commercial power supply grounding), and warns of incorrect connection by buzzer. The resistance measurement is increased to 115% of range Accessories for Greater Convenience High durability measurement switches with dust-resistant construction Auxiliary resistance (P/C) check feature Check the ground condition of auxiliary grounding resistance, which can cause measurement error. • Convenient cable winder for total away the measurement cable. • Carrying case holds everything for total portability. Easy-grip elastomer knob Measurement method and frequency switching switches Push a button to select simple measurement (two electrode method). And, a feature to select the measurement frequency in order to reduce the influence of grounding voltage or grounding current due to high power supply frequency. 3 3143 Specifications 3151 Specifications Measurement Item Measurement Range Accuracy Grounding Resistance 20.0 to 49.9 Ω ± 10% rdg. 50.0 to 500.0 W ± 5% rdg. Measurement Item Grounding Resistance (Temperature and humidity: Within rated operating temperature and humidity range.) ●Display: 4-digit LCD, values above 999.9 Ω displayed as "OF" ●Influence of grounding voltage: ± 5% rdg. for 0 to 10 V ●Principle of operation: voltage comparison method (Measurement of voltage at loop impedance serial resonance) ●Open circuit voltage: AC 1 Vp typ ●Measurement current: AC 3.6 mA max (With terminals shorted) ●Measurement frequency: 100 kHz to 1.5 MHz ●Features: • Energy saving mode: after 3 minutes with no operation, displays "HOLD" and enters the standby state • Resonance indicator: bar graph indicator shows approximate location of resonance point • Battery check: battery light flashes when the power supply voltage drops ●Operating temperature and humidity: 0 to 40˚C, 80% rh maximum (no condensation) ●Storage temperature and humidity: -10 to 50˚C, 80% rh maximum (no condensation) ●Applicable standards: • Safety: EN61010-1 + A2, overvoltage category I, pollution level 2 • EMC: EN61326-1 + A1 class B ●Power supply: LR6 alkaline battery × 4 ●Operating time: 8 hours continuous (23˚C reference value) ●Approximate dimensions and weight: 155 (W) × 98 (H) × 49 (D) mm (not including projections), 380 g (main unit only) ●Accessories: MEASURING CABLE 9265 (black 1 m, red 20 m, one each; CABLE WINDER 9216 × 1) PORTABLE CASE 9338 Measurement Range Nominal Deviation 10 Ω (0 to 11.5 Ω) ± 2.5 % f.s. 100 Ω (0 to 115 Ω) ± 2.5 % f.s. 1000 Ω (0 to 1150 Ω) ± 2.5 % f.s. 30 V (0 to 30 V) ± 3.0 % f.s. Grounding Voltage (Temperature and humidity: 23˚C ± 5˚C, 80% rh maximum) (100Ω/1000Ω ranges only with 2 electrode measurement) ●Influence of auxiliary grounding resistance: ± 5% for a fluctuation of 0 to 5 kΩ ●Influence of grounding voltage: ± 2% for 0 to 5 V ± 5% for 0 to 10 V (for 50/60 Hz) ± 5% for 0 to 3 V (for DC, 162/3, 400 Hz) ●Influence of power supply voltage: within nominal deviation for DC 6 to 10 V ●Operating method: AC potentiometer method ●Open circuit voltage: AC 50V max ●Measurement current: AC 15 mA max (AC 3 mA max when using the two electrode method) ●Measurement frequency: 575 Hz (with 3a or 2a selected) or 600 Hz (with 3b or 2b selected) ●Operating temperature and humidity: 0 to 40˚C, 80% rh maximum (no condensation) ●Storage temperature and humidity: -10 to 50˚C, 80% rh maximum (no condensation) ●Applicable standards: • Grounding resistance meter: EN61557-5 • Safety: EN61010-1 + A2 / EN61010-2-031, overvoltage category II, pollution level 2 • EMC: EN61326-1+A1 ●Environment protection: IP40 (EN60529:1991) ●Overvoltage protection: AC 250 V, 1 minute (between E - P (S), E - C (H) terminals) ●Power supply: R6P manganese battery × 6, or LR6 alkaline battery × 6 ●Operating time: Approx 350 operations (using R6P battery) Approx 1100 operations (using LR6 battery) (30 seconds measurement / 30 seconds off condition) ●Approximate dimensions and weight: 164 (W) × 119 (H) × 88 (D) mm (not including protrusions), 800 g (main unit only) ●Accessories: AUXILIARY GROUNDING RODS 9214 × 2 MEASURING CABLE 9215 (black 5 m, yellow 10 m, red 20 m, one each; CABLE WINDER 9216 × 3) PORTABLE CASE 9393 ●Optional accessory EARTH NETS 9050 (set of two) Use in places where auxiliary grounding rods cannot be inserted (but where water can penetrate) HIOKI (Shanghai) Sales & Trading Co., Ltd. : 1608-1610 Shanghai Times Square Office, 93 Huai Hai Zhong Road, Shanghai, P.R.China POSTCODE: 200021 TEL +86-21-6391-0090/0092 FAX +86-21-6391-0360 E-mail: [email protected] HEAD OFFICE : 81 Koizumi, Ueda, Nagano, 386-1192, Japan TEL +81-268-28-0562 / FAX +81-268-28-0568 E-mail: [email protected] HIOKI USA CORPORATION : 6 Corporate Drive, Cranbury, NJ 08512 USA TEL +1-609-409-9109 / FAX +1-609-409-9108 E-mail: [email protected] DISTRIBUTED BY Beijing Office : A-2602 Freetown, 58 Dong San Huan Nan Road Beijing, P.R.China POSTCODE: 100022 TEL +86-10-5867-4080/4081 FAX +86-10-5867-4090 E-mail: [email protected] Guangzhou Office : Room A-3206, Victory PlazaServices Center, No.103, Tiyuxi Road, Guangzhou, P.R.China POSTCODE:510620 TEL +86-20-38392673/2676 FAX +86-20-38392679 E-mail: [email protected] All information correct as of Sep. 30, 2009. All specifications are subject to change without notice. 3143E5-99E Printed in Japan