Danfoss FC 102

Full load
% Full load current
& speed
500
100
0
0 12,5 25 37,5 50Hz
200
300
400
600
700
800
4
3
2
1
175HA227.10
Illustration 2.14 A Frequency Converter Does Not Consume
More Than Rated Current
1 VLT
®
HVAC Drive
2 Star/delta starter
3 Soft-starter
4 Start directly on mains
Table 2.8 Legend to Illustration 2.14
2.7.9
Using a Frequency Converter Saves
Money
The example on the following page shows that a lot of
equipment is not required when a frequency converter is
used. It is possible to calculate the cost of installing the 2
different systems. In the example on the following page,
the 2 systems can be established at roughly the same
price.
2.7.10
Without a Frequency Converter
D.D.C. =
Direct Digital
Control
E.M.S. =
Energy
Management
system
V.A.V. = Variable Air Volume
Sensor P = Pressure
Sensor
T
= Temperature
Table 2.9 Abbreviations used in Illustration 2.15 and Illustration 2.16
M
- +
M
M
x6 x6
x6
175HA205.12
Valve
posi-
tion
Starter
Fuses
LV
supply
P.F.C
Flow
3-Port
valve
Bypass
Return
Control
Supply
air
V.A.V
outlets
Duct
P.F.C
Mains
Fuses
Starter
Bypass
supply
LV
Return
valve
3-Port
Flow
Control
Valve
posi-
tion
Starter
Power
Factor
Correction
Mains
IGV
Mechanical
linkage
and vanes
Fan
Motor
or
actuator
Main
B.M.S
Local
D.D.C.
control
Sensors
PT
Pressure
control
signal
0/10V
Temperature
control
signal
0/10V
Control
Mains
Cooling section Heating section
Fan sectionInlet guide vane
Pump Pump
Illustration 2.15 Traditional Fan System
2.7.11
With a Frequency Converter
175HA206.11
Pump
Flow
Return
Supply
air
V.A.V
outlets
Duct
Mains
Pump
Return
Flow
Mains
Fan
Main
B.M.S
Local
D.D.C.
control
Sensors
Mains
Cooling section Heating section
Fan section
Pressure
control
0-10V
or
0/4-20mA
Control
temperature
0-10V
or
0/4-20mA
Control
temperature
0-10V
or
0/4-20mA
VLT
M
- +
VLT
M
M
P
T
VLT
x3 x3
x3
Illustration 2.16 Fan System Controlled by Frequency
Converters.
Introduction to VLT® HVAC D... Design Guide
MG11BC02 Danfoss A/S © Rev. 06/2014 All rights reserved. 23
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