Motor Soft Start; Resonance Damping; Temperature-Controlled Fans; Emc Compliance - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview

2.5.15 Motor Soft Start

The adjustable frequency drive supplies the right amount
of current to the motor to overcome load inertia and bring
the motor up to speed. This avoids full AC line voltage
being applied to a stationary or slow-turning motor, which
generates high current and heat. This inherent soft start
feature reduces thermal load and mechanical stress,
extends motor life, and provides quieter system operation.

2.5.16 Resonance Damping

High frequency motor resonance noise can be eliminated
through resonance damping. Automatic or manually
selected frequency damping is available.

2.5.17 Temperature-controlled Fans

The internal cooling fans are temperature controlled by
sensors in the adjustable frequency drive. 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.

2.5.18 EMC Compliance

Electromagnetic interference (EMI) or radio frequency
interference (RFI, in case of radio frequency) is disturbance
that can affect an electrical circuit due to electromagnetic
induction or radiation from an external source. The
adjustable frequency drive 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 3.2.2 EMC Test Results.
2.5.19 Current Measurement on All Three
Motor Phases
Output current to the motor is continuously measured on
all three phases to protect the adjustable frequency drive
and motor against short circuits, ground faults, and phase
loss. Output ground faults are instantly detected. If a
motor phase is lost, the adjustable frequency drive stops
immediately and reports which phase is missing.
MG20N622
Design Guide
2.5.20 Galvanic Isolation of Control
All control terminals and output relay terminals are galvan-
ically isolated from line power. This means the controller
circuitry is completely protected from the input current.
The output relay terminals require their own grounding.
This isolation meets the stringent protective extra-low
voltage (PELV) requirements for isolation.
The components that make up the galvanic isolation are:
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2.6 Custom Application Functions

Custom application features are the most common features
programmed in the adjustable frequency drive for
enhanced system performance. They require minimum
programming or set-up. Understanding that these features
are available can optimize the system design and possibly
avoid introducing redundant components or functionality.
See the programming guide for instructions on activating
these functions.

2.6.1 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 adjustable frequency drive to
calculate optimal performance and efficiency with the
motor. Running the AMA procedure also maximizes the
automatic energy optimization feature of the adjustable
frequency drive. AMA is performed without the motor
rotating and without uncoupling the load from the motor.

2.6.2 Motor Thermal Protection

Motor thermal protection can be provided in three ways:
•
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Terminals
Power supply, including signal isolation.
Gate drive for the IGBTs, trigger transformers, and
optocouplers.
The output current Hall effect transducers.
Via direct temperature sensing via one of the
following:
- PTC sensor in the motor windings and
connected on a standard AI or DI.
- PT100 or PT1000 in the motor windings
and motor bearings, connected on VLT
Sensor Input Card MCB 114.
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