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MITSUBISHI ELECTRIC
FR-F 740 EC/E1
SYSTEM DESCRIPTION
Intelligent Technology that Cuts Power Consumption
POWER
Hz
PU
EXT
MON
MODE
SET
REV
FWD
STOP
RESET
A
V
ALARM
REV
FWD
DATAPORT
MITSUBISHI
F5
0
0
Exhaust
Air
Air filter
Belt
Blower
Motor
Heat
exchanger
Duct
Cold source (chiller)
Heat source (heat pump)
Cold/hot
water
Saving power with Mitsubishi
frequency converters
Reducing consumption and optimising the
utilisation of our valuable energy resources
is one of the greatest global environmental
challenges of our age.
Energy conservation mode is a standard
feature of the intelligent controller. It dyna
-
mically adjusts the voltage to motor requi
-
rements, eliminating unnecessary power
losses, which helps to further reduce po
-
wer consumption. Frequency inverters are
particularly effective at conserving energy
when they are used to control pumps and
fans.
Theamountofenergyconservation(hyste
-
resis) depends on the speed/torque fluc
-
tuations. The graph below provides an im
-
pressive example of the results of
intelligent control in a fan system.
How do frequency inverters
conserve energy?
The illustration below shows a blower sys
-
tem in which the air flow is regulated by
controlling the motor with a frequency in
-
verter instead of with a damper on the ex
-
haust side.
The graph below compares the motor po
-
wer consumption of the frequency inverter
and damper solutions. At a flow rate of
60% the curve shows that the frequency
inverter system consumes a full 60% less
power than the motor with the damper
system.
Potential savings
In addition to the ecological benefits fre
-
quency inverters can also save a great deal
of money by radically cutting power con
-
sumption.
Example:
Based on the graph on the left and an elec
-
tricity price of 14 cents per kWh, the follo
-
wing savings can be achieved with a sys
-
tem using a 75 kW motor:
Ȝ
Conventionalmechanical solution
At an air throughput of 60% the power
consumption is 90%, resulting in the
following annual costs:
75 kW x 0.9 x €0.14 x 24 h x 365 days
= €82,782
Ȝ
Frequencyinverter solution
At an air throughput of 60% the power
consumption is 30%, resulting in the
following annual costs:
75 kW x 0.3 x €0.14 x 24 h x 365 days
= €27,594
This means that the inverter solution saves
€55,188 per year compared to the conven-
tional mechanical system!
Clearly, a frequency inverter will pay for
itself in a very short time – and one must
also remember that the potential savings
increase with the power ratings of the
motors used.
Energy savings control
The effect of energy savings can be confir-
med using the control panel, via the
output terminals (CA, AM) and via net
-
works (network option required) with the
newly developed energy saving monitor.
100
90
70
60
50
40
30
20
10
0
0 40 80 10060
80
Conserved
energy
Damper control (exhaust side)
Air quantity (%)
Power consumption (%)
Inverter control
100
1000
Power consumption (%)
Rotational speed (= air quantity) (%)
Mechanical solution
Constant torque
pattern (Pr.no.14 = 0)
Energy conservation mode
(Pr.no.14=1,Pr.no.60=9)
Frequency inverter
control
Reduced torque
pattern (Pr.no.14= 1)
Application with potential for power savings
The power P
L
required for a
fan or pump is proportional
to the cube of the rotational
speed
Example of airhandling unit
Power
supply
3-phase 400 V
Frequencyinverter