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.
4.1.11 Automatic Derating for High Carrier
Frequency
The frequency converter is designed for continuous, full
load operation at carrier frequencies between 3.0 and 4.5
kHz. A carrier frequency higher than 4.5 kHz generates
increased heat in the frequency converter and requires the
output current to be derated.
An automatic feature of the frequency converter is load-
dependent carrier frequency control. This feature allows
the motor to benefit from as high a carrier frequency as
the load permits.
4.1.12 Power Fluctuation Performance
The frequency converter withstands mains fluctuations
such as transients, momentary dropouts, short voltage
drops and surges. The frequency converter automatically
compensates for input voltages
±
10% from the nominal to
provide full rated motor voltage and torque. With auto
restart selected, the frequency converter automatically
powers up after a voltage trip. And with flying start, the
frequency converter synchronises to motor rotation prior
to start.
4.1.13 Resonance Damping
High frequency motor resonance noise can be eliminated
through the use of resonance damping. Automatic or
manually selected frequency damping is available.
4.1.14 Temperature-controlled Fans
The internal cooling fans are temperature controlled by
sensors in the frequency converter. The cooling fan often is
not running during low load operation or when in sleep
mode or standby. This reduces noise, increases efficiency,
and extends the operating life of the fan.
4.1.15 EMC Compliance
Electromagnetic interference (EMI) or radio frequency
interference (RFI, in case of radio frequency) is disturbance
which can affect an electrical circuit due to electro-
magnetic induction or radiation from an external source.
The frequency converter is designed to comply with the
EMC product standard for drives IEC 61800-3 as well as the
European standard EN 55011. To comply with the emission
levels in EN 55011, the motor cable must be shielded and
properly terminated. For more information regarding EMC
performance, see
chapter 5.2.1 EMC Test Results
4.1.16 Galvanic Isolation of Control
Terminals
All control terminals and output relay terminals are galvan-
ically isolated from mains power. This means the controller
circuitry is completely protected from the input current.
The output relay terminals require their own grounding.
This isolations meets the stringent protective extra-low
voltage (PELV) requirements for isolation.
The components that make up the galvanic isolation are
•
Power supply, including signal isolation
•
Gate drive for the IGBTs, the trigger transformers
and optocouplers
•
The output current Hall Effect transducers
4.2 Custom Application Features
These are the most common features programmed for use
in the frequency converter for enhanced system
performance. They require minimum programming or set
up. Understanding that these features are available can
optimie a system design and possibly avoid introducing
redundant components or functionality. See the product
specific
Programming Guide
, for instructions on activating
these functions.
4.2.1 Automatic Motor Adaptation
Automatic motor adaptation (AMA) is an automated test
procedure used to measure the electrical characteristics of
the motor. AMA provides an accurate electronic model of
the motor. It allows the frequency converter to calculate
optimal performance and efficiency with the motor.
Running the AMA procedure also maximises the automatic
energy optimisation feature of the frequency converter.
AMA is performed without the motor rotating and without
uncoupling the load from the motor.
Product Features
VLT
®
AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW
38
MG33BF02 - Rev. 2013-12-20
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