FC101 Design Guide

3 Product Overview
3.1 Advantages
3.1.1 Why use a Frequency Converter for
Controlling Fans and Pumps?
A frequency converter takes advantage of the fact that
centrifugal fans and pumps follow the laws of propor-
tionality for such fans and pumps. For further information,
see chapter 3.1.3 Example of Energy Savings.
3.1.2 The Clear Advantage - Energy Savings
The clear advantage of using a frequency converter for
controlling the speed of fans or pumps lies in the
electricity savings.
When comparing with alternative control systems and
technologies, a frequency converter is the optimum energy
control system for controlling fan and pump systems.
Figure 3.1 Fan Curves (A, B, and C) for Reduced Fan Volumes
120
100
80
60
40
20
0
20 40 60 80 100 120 140 160 180
120
100
80
60
40
20
0 20 40 60 80 100 120 140 160 180
Volume %
Volume %
INPUT POWER % PRESSURE %
SYSTEM CURVE
FAN CURVE
A
B
C
130BA781.11
ENERGY
CONSUMED
Figure 3.2 Energy Savings with Frequency Converter Solution
When using a frequency converter to reduce fan capacity
to 60% - more than 50% energy savings may be obtained
in typical applications.
3.1.3 Example of Energy Savings
As shown in Figure 3.3, the ow is controlled by changing
the RPM. By reducing the speed by only 20% from the
rated speed, the ow is also reduced by 20%. This is
because the ow is directly proportional to the RPM. The
consumption of electricity, however, is reduced by 50%.
If the system in question only needs to be able to supply a
ow that corresponds to 100% a few days in a year, while
the average is below 80% of the rated ow for the
remainder of the year, the amount of energy saved is even
more than 50%.
Product Overview
VLT
®
HVAC Basic Drive FC 101
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