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5 Product Features
5.1 Automated Functions
These automated functions fall into 3 categories:
•
Turned on by default, but can be disabled by
programming.
•
Turned off by default, but can be enabled by
programming.
•
Always enabled.
5.1.1 Automatic Energy Optimization
Automatic energy optimization (AEO) is used in HVAC
applications. This feature directs the frequency converter to
monitor continuously the load on the motor and adjust
the output voltage to maximize efficiency. Under light
load, the voltage is reduced and the motor current is
minimized. The motor benefits from increased efficiency,
reduced heating, and quieter operation. There is no need
to select a V/Hz curve because the frequency converter
automatically adjusts motor voltage.
5.1.2 Automatic Switching Frequency
Modulation
The frequency converter generates short electrical pulses
to form an AC wave pattern. The carrier frequency is the
rate of these pulses. A low carrier frequency (slow pulsing
rate) causes noise in the motor, making a higher carrier
frequency preferable. A high carrier frequency, however,
generates heat in the frequency converter which can limit
the amount of current available to the motor. The use of
insulated gate bipolar transistors (IGBT) means high-speed
switching.
Automatic switching frequency modulation regulates these
conditions automatically to provide the highest carrier
frequency without overheating the frequency converter. By
providing a regulated high carrier frequency, it quiets
motor operating noise at slow speeds, when audible noise
control is critical, and produces full output power to the
motor when the demand requires.
5.1.3 Automatic Derating for High Carrier
Frequency
The frequency converter is designed for continuous and
full load operation between the carrier frequencies
between the minimum and maximum frequencies shown
in
. If the carrier frequency is higher than the
maximum frequency, the output current of the frequency
converter is derated automatically.
Power
kW (hp)
Switching frequency
Hz
Minimum
Hz
Maximum
Hz
Factory Setting
Hz
250 (350)
3000
2000
8000
3000
315 (450)
2000
1500
6000
2000
355 (500)
2000
1500
6000
2000
400 (550)
2000
1500
6000
2000
450 (600)
2000
1500
6000
2000
500 (650)
2000
1500
6000
2000
560 (750)
2000
1500
6000
2000
630 (900)
2000
1500
6000
2000
710 (1000)
2000
1500
6000
2000
800 (1200)
2000
1500
6000
2000
Table 5.1 Carrier Frequency Operational Ranges for 380–500 V
Product Features
Design Guide
MG37N102
Danfoss A/S © 6/2016 All rights reserved.
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