NADXB Alarming and Analyzing Instruments, 
NADXC Electric Harmonic Measuring tester,
It meets whole requirements of GB/T1459～93 test virtual value, and positive ,reverse and zero sequence component of current and voltage
Measuring area: content of voltage harmonic, distortion factor of phase-angle and current voltage
Virtual value of current harmonics, distortion factor of phase-angle and total voltage harmonics
Range of measuring harmonics: fundamental wave -51times harmonics 
Way of input signals: voltage, current & phase
Print: printed three-phase waveforms, statistic of the testing results, automatic printed three-phase results.
The key technical indexes:
1．Way and range of input signal
   A．Three-phase voltage and three-phase current
   B. voltage test range: 10-240V(or 20-400V)
   C. current test range: 0.05-6A (or0.1-12A)
   D. tracking range of fundamental harmonics frequency
2. Input impendence: voltage side≥200kΩ, current side≤20mΩ
3. Measuring accuracy: measuring error of fundamental: ≤0.5%
4. Measuring times of harmonics: 5-51
5. Statistical times: 5～96 times are choiceable
6. Timing space of orientation in time: 0～999 minutes are choiceable
7. setting range of continuous limited number: 0～999
8. time of equipments' power supply source: 220V±15%; 50Hz±5%; THDu±≤8.0%; 20VA