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Case Studies > UPS Operation
Single phase UPS input and output AC voltage and current and internal battery voltage and current were monitored by a PQPro™ power quality analyzer/data recorder. The PQPro™ was configured to record continuous waveform data with a resolution of 65 microseconds (256 samples/cycle) as well as AC RMS and DC voltages and currents with a resolution of 200 milliseconds (RMS update every 12 cycles). Input AC voltage was removed twice during the recording.

The UPS monitored was inexpensive with a square wave output when input voltage was removed. When input voltage was present the UPS inverter was bypassed.


Fig.1
Figure 1: Input (Red) and Output (Black) AC RMS Voltage and Current

Fig.2
Figure 2: Battery Voltage (Green) and Current (Black)

Fig.3
Figure 3: Input (Red) and Output (Black) Voltage at the time of input disconnect. Note: Input voltage was measured on the line side of the UPS input disconnect switch
Fig.4
Figure 4: Input (Red) and Output (Black) Voltage at the time of input re-connect

Fig.5
Figure 5: Input (Red) and Output (Black) Current at the time of input disconnect

Fig.6
Figure 6: Input (Red) and Output (Black) Current at the time of input re-connect

Fig.7
Figure 7: 3rd Harmonic Output Voltage (Red) and Current (Black) Trend

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