Estimated input power for the commercial power supply operation
(Pr.892, Pr.893, Pr.894)
• Select the pattern of the commercial power supply operation from among four patterns (discharge damper control (fan),
suction damper control (fan), valve control (pump) and commercial power drive), and set it in Pr.894 Control selection
during commercial power-supply operation.
• Set the motor capacity (pump capacity) in Pr.893 Energy saving monitor reference (motor capacity).
• Refer to the following graph to find the rate of power consumption (%) during commercial power supply operation based
on the selected pattern and the rate of motor rotations per minute with respect to the rated speed (the result of dividing the
present output frequency by Pr.3 Base frequency setting).
• The estimated input power (kW) for the commercial power supply operation is calculated from the motor capacity set in
Pr.893, the setting of Pr.892 Load factor, and the rate of power consumption using the following formula.
Estimated consumed power during
commercial power supply operation (kW)
• If the output frequency rises to the setting of Pr.3 Base frequency or higher, it stays at a constant value because the rotations
per minute cannot rise higher than the power supply frequency during commercial power supply operation.
Annual energy saving and its monetary value (Pr.899)
• When the operation time rate (ratio of the time period in year when the inverter drives the motor) [%] is set in Pr.899, the
annual energy saving effect can be estimated.
• When the inverter is operated in specific patterns, the estimate annual energy saving can be calculated by measuring the
energy saving in a certain period.
• Refer to the following procedure to set the operation time rate.
Estimate the average operation time per day (h/day).
Calculate the operation days per year (days/year) using the following formula: Average operation days per month ×
Calculate the annual operation time (h/year) from values determined in Step 1 and Step 2, using the following
Annual operation time (h/year) = average time (h/day) × number of operation days (days/year)
Calculate the operation time rate using the following formula, and set it in Pr.899.
Operation time rate (%) =
Commercial power-supply drive
Inlet damper control
0 10 20 30 40 50 60 70 80 90100110
Ratio of speed to rating [%]
Consumed power (%)
＝ Pr.893 (kW) ×
Annual operation time (h/year)
24 (h/day) × 365 (days/year)
5.8 (M) Item and output signal for monitoring