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Flow :
Q1
Q2
=
n1
n2
Pressure :
H1
H2
=
(
n1
n2
)
2
Power :
P1
P2
=
(
n1
n2
)
3
2.7.4 Example with Varying Flow over 1 Year
The example below is calculated on the basis of pump characteristics ob-
tained from a pump datasheet.
The result obtained shows energy savings in excess of 50% at the given
flow distribution over a year. The pay back period depends on the price
per kwh and price of frequency converter. In this example it is less than
a year when compared with valves and constant speed.
Energy savings
P
shaft
=P
shaft output
Flow distribution over 1 year
Automation VT Drive FC322 Design Guide
2 Introduction to VLT Automation VT Drive
MG.20.X1.22 - VLT
®
is a registered Danfoss trademark
21
2
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