| Measuring Principle for Ior Leakage Current |
It is observed that the load connected to the low voltage side of the transformer generates the harmonics in the current flow in the power line. And it is observed that5th and 7th harmonics current causes the phenomenon of voltage drop at the high voltage side of the transformer.
This voltage drop at high voltage side added the drops of other related power line generates the terminal voltage with harmonics at low voltage side. Thus, 5th and 7th harmonics is generated at the low voltage side by the influence of high voltage side, and it is considered the ratio of 5th and 7th harmonics current is always constant. Consequently, the ratio of 5th and 7th harmonics flowing into earth line is changed proportionally according to the ratio of capacitive component and resistive component in the circuit.
On the other hand, when the long line is used, it is observed that the fundamental current component into earth line is increased proportionally and the ratio of 5th and 7th harmonics is also changed due to the increase of capacitance and inductance of the circuit. By above fact, the calculation factor can be obtained by the measured ratio of 5th and 7th harmonics current and fundamental current component into earth line. Thus,the resistive leakage current Iorcan be obtained by the computation of the culculation factor and compensation factor of the circuit.
And it is reported that the satisfactory test result was observed from our many practical field tests in Japan.
|
| Measuring function |
Load current, leakage current (Io)
Resistive leakage current (Ior)
Harmonics current and voltage
(Fundamental, 3rd, 5th, 7th, 11th and 13th)
AC Voltage |
| Measuring method |
Dual slope integration mode |
| Display |
3.5 digit LCD, max. reading of 4000 |
| Range |
AC 0-40mA, 400mA, 4A, 40A, 300A,
AC 0～500V |
| Accuracy |
Measuring Function/Range/Resolution/Accuracy
AC Current/40mA/0.01mA/±1.0%rdg±8dgt
AC Current/400mA/0.1mA/±1.0%rdg±8dgt
AC Current/4A/0.001A/±1.0%rdg±8dgt
AC Current/40A/0.01A/±1.0%rdg±8dgt
AC Current/300A/0.1A/±1.0%rdg±1%FS
AC Voltage/500V/0.1V/±1.0%rdg±8dgt |
| Accuracy for Harmonics Current and Voltage |
Fundamental, 3rd, 5th, 7th : 1%rdg±5dgt±AC current and voltage accuracy
11th and 13th Harmonics : 2%rdg±5dgt±AC current and voltage accuracy
(Min. fundamental input current : more than 2% of each current) |
| CT opening capability |
φ40mm |
| AC Conversion |
Average sensing rms reading |
| Input Frequency |
45-65Hz |
| Over range indication |
"OL" mark on LCD |
| Low battery indication |
"Battery mark" on LCD |
| Auto power off function |
Approx. 10 minutes later after final key operation |
| Data hold indication |
"DH" mark on LCD |
| Influence of external magnetic field |
Less than 5mA (nearby 100A conductor) |
| Sampling |
2 times/sec, 1 time/6 sec. for Ior measurement |
| Limitation of circuit voltage |
Less than AC 500V |
| Withstanding Voltage |
AC 2200V, 1minute |
| Operating Temperature |
0℃~40℃, < 80%RH ( Without condensation ) |
| Storage Temperature |
10℃~60℃, < 70%RH ( Without condensation ) |
| Power supply |
1.5V ("AAA" sixe, um-4)x3 or AC adaptor (Option) |
| Power consumption |
Approx. 8mA (Approx. 60 hours continuous) |
| Size and Weight |
70(W)x223(H)x34(D)mm
Approx. 440g including batteries
|