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Output current limit
The inverter turns off to self-protect the internal components when the maximum current limits are reached.
Overtemperature
The inverter turns off to self-protect the internal components when the maximum temperature limits are reached.
Electronic thermal relay (ETR)
ETR is an electronic feature that simulates a bimetal relay based on internal measurements. See also 3.2.2.2 Motor Thermal Protec-
tion.
N O T I C E
In regulation wih UL 60730-1 certified products, the output overload conditions, such as motor overload (ETR), cannot be disa-
bled.
3.3.3 Temperature Protection
The VLT® Compressor Drive CDS 803 offers various built-in temperature protection features for monitoring the operation environ-
ment.
3.3.3.1 Minimum and Maximum Temperature Protection
The drive has built-in temperature sensors and reacts immediately to critical temperature limits. At low temperature, a warning will
be triggered. If high temperature limits are exceeded, the drive trips on an alarm and turns off all outputs.
3.3.3.2 Automatic Temperature Derating
Automatic temperature derating can be enabled via parameterization to allow continued operation during high temperatures.
3.3.3.3 Temperature-controlled Fans
Sensors in the drive regulate the operation of the internal cooling fans. Often, the cooling fans do not run during low-load opera-
tion, when in sleep mode, or in standby. The sensors reduce noise, increase efficiency, and extend the operating life of the fan.
3.3.4 Internal Protection
The VLT® Compressor Drive CDS 803 offers various built-in internal protection features ensuring that the drive is fully operational.
3.3.4.1 DC Overvoltage Protection
The internal DC-link voltage is increased when the motor acts as a generator. This occurs in the following situations:
The load drives the motor (at constant output frequency from the drive), that is, the load generates energy.
During deceleration (ramp-down) if the moment inertia is high, the friction is low, and the ramp-down time is too short for the
energy to be dissipated as a loss in the drive, the motor, and the installation.
Incorrect slip compensation setting may cause higher DC-link voltage.
Back EMF from PM motor operation. If coasted at high RPM, the PM motor back EMF may potentially exceed the maximum
voltage tolerance of the drive and cause damage. To prevent this, the maximum output frequency is automatically limited
based on an internal calculation. This calculation is based on motor parameterizations.
Monitoring of the internal voltage ensures that the drive trips when the DC-link voltage is too high. The drive turns off the output to
protect itself when a certain voltage level is reached. Enabling overvoltage control (OVC) reduces the risk of the drive tripping due
to an overvoltage on the DC link. This is controlled by automatically extending the ramp-down time.
3.3.4.2 Internal Faults
The drive has various internal self-monitoring functions which ensure that the drive is fully operational. For warning and alarm de-
tails, refer to VLT® Compressor Drive CDS 803 Programming Guide listed in 1.2 Additional Resources.
3.4 Ecodesign for Power Drive Systems
The Ecodesign Directive is the legislative framework that sets requirements on all energy-related products in the domestic, com-
mercial, and industrial sectors throughout Europe.
The Ecodesign requirements are only mandatory within the European Union. These requirements are like the legislative require-
ments for energy-related products which apply in North America and Australia.
Terms like Complete Drive Module (CDM) and Power Drive Systems (PDS) are used to define the elements in the design. The objec-
tive is to make more efficient and fewer energy consuming designs.
AJ330233902305en-000201 / 130R0596 | 21Danfoss A/S © 2021.05
Product Overview
VLT® Compressor Drive CDS 803
Design Guide
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