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5.20 Power factor and power input
During the loaded state of the digital scroll, when the compressor operates at full capacity, the power
factor of the motor is equivalent to standard fixed-speed scrolls. However, during part-load, when the
scrolls are unloaded, the power factor is lower.
The power input of a digital scroll varies between loading and unloading processes. During
unloading, the power input is approximately 10 % of the maximum power input. Even though the
capacity regulation is a dynamic process, the average power consumption can be calculated with
the following method:
P
= (P
x Proportion of loaded time) + (0.1 x P
av
op
where:
P
= Digital scroll average power consumption
av
P
= Compressor power input operation point
op
P
= Maximum power input in the table of the application envelope
max
Example: Cooling capacity requirement = 40 %, P
P
= (3.23 kW x 0.4) + (0.1 x 5.33 x 0.6) = 1.61 kW
av
NOTE: An estimate of the digital scroll energy consumption only by measuring the amps
gives wrong results. For a realistic estimate, a correct power measurement must be made.
AGL_Ref_DG_YBDK1E_EN_Rev04
x Proportion of unloaded time)
max
= 3.23 kW, P
= 5.33 kW
op
max
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