Measuring Inrush Current; Inrush Current; Figure 4-21 Inrush Current Example - NF DP Series Instruction Manual

3. Press the [Next] soft-key to display the measured values for order 11 to 20. Press the [Prev]
soft-key to return to the original view. Switch the view in the same manner for the measured
values over order 21.
4. Press the CANCEL key to return to the Continuous function view.
4.5

Measuring Inrush Current

4.5.1 Inrush Current

On an electric device using a capacitor input type rectifier circuit for power input, an excessive
current in comparison to the Normal state may flow for a short period of time immediately after the
start of power supply. This current is called inrush current. If such a big current flows to the power
line, the supply voltage may drop due to the impedance of the power line. Therefore, the inrush
current is restricted below a certain level in some standards.
Figure 4–21 shows the inrush current waveform of a small electric drill. The inrush current flows at
14 A peak, which is about four times of the rated current of 3.5 A.
DP Series/DP Series Type R
Voltage
電圧
100V/div
Current
電流
10A/div

Figure 4-21 Inrush Current Example

4.5 Measuring Inrush Current

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