Mitsubishi Electric FR-A820-00046 Instruction Manual page 540

(M) Monitor display and monitor output signal
● The estimated value of the consumed power during commercial power supply operation [kW] is
calculated from the motor capacity set in Pr. 893 and Pr. 892 "Load factor" with the following
formula.
Estimated consumed power during
commercial power supply operation [kW]
NOTE In commercial power supply operation, because the rotations per minute cannot rise higher than
the power supply frequency, if the output frequency rises to Pr. 3 "Base frequency" or higher, it
stays at a constant value.
Annual power saving amount and power cost savings (Pr. 899)
● When the operation time rate [%] (ratio of time in year that the inverter actually drives the motor)
is set in Pr. 899, the annual energy saving effect can be estimated.
● When the operation pattern is determined to a certain extent, the estimated value of the annual
power saving amount can be calculated by measuring the power saving in a certain measurement
period.
● Refer to the following to set the operation time rate.
Estimate the average time of operation per day [h/day].
Calculate the number of operation days per year [days/year].
(Average number of operation days per month × 12 months)
Calculate the annual operation time [h/year] from
Annual operation time [h/year] = average time [h/day] × number of operation days [days/year]
Calculate the operation time rate and set it in Pr. 899.
Operation time rate (%) =
Example Setting example for operation time rate:
When operation is performed about 21 h per day for an average 16 operation days per month:
Annual operation time = 21 [h/day] × 16 [days/month] × 12 months = 4032 [h/year]
Operation time rate [%] =
Set 46.03% in Pr. 899.
● Calculate the annual power saving amount from Pr. 899 "Operation time rate (estimated value)"
and the average power saving monitor.
Annual power saving amount
[kWh/year]
● When the power cost per hour is set in Pr. 896 "Power unit cost", the annual power cost savings
can be monitored.
Annual power cost saving = Annual power saving amount [kWh/year] × Pr. 896
NOTE During regenerative driving, make calculation on the assumption that "power saving = power dur-
ing commercial power supply operation (input power = 0)".
5 - 360
= Pr. 893 [kW] ×
Annual operation time
24 h/day] × 365 days/year]
[ [
4032 [h/year]
24 [h/day] × 365 [days/year]
With Pr. 898 = 10 or 9999, average
=
power saving [kW] during cumulative
Consumed power [%]
100
and .
h/year]
[
× 100 [%]
× 100 [%] = 46.03%
× 24 h × 365 days ×
Parameters
Pr. 892 [%]
×
100
Pr. 899
100