System Integration; Ambient Operating Conditions; Humidity; Temperature - Danfoss VLT AutomationDrive FC 301 Design Manual

System Integration

5 System Integration

5.1 Ambient Operating Conditions

5.1.1 Humidity

Although the frequency converter can operate properly at
high humidity (up to 95% relative humidity), condensation
must always be avoided. There is a specific risk of conden-
sation when the frequency converter is colder than moist
ambient air. Moisture in the air can also condense on the
electronic components and cause short circuits. Conden-
sation occurs to units without power. It is advisable to
install a cabinet heater when condensation is possible due
to ambient conditions. Avoid installation in areas subject
to frost.
Alternatively, operating the frequency converter in stand-
by mode (with the unit connected to the mains) reduces
the risk of condensation. However, ensure the power
dissipation is sufficient to keep the frequency converter
circuitry free of moisture.

5.1.2 Temperature

Minimum and maximum ambient temperature limits are
specified for all frequency converters. Avoiding extreme
ambient temperatures prolongs the life of the equipment
and maximises overall system reliability. Follow the
recommendations listed for maximum performance and
equipment longevity.
•
Although converters can operate at temperatures
down to -10 °C, proper operation at rated load is
only guaranteed at 0 °C or higher.
•
Do not exceed the maximum temperature limit.
•
The lifetime of electronic components decreases
by 50% for every 10 °C when operated above its
design temperature.
•
Even devices with IP54, IP55, or IP66 protection
ratings must adhere to the specified ambient
temperature ranges.
•
Additional air conditioning of the cabinet or
installation site may be required.

5.1.3 Temperature and Cooling

The frequency converters have built-in fans to ensure
optimum cooling. The main fan forces the air flow along
the cooling fins on the heat sink, ensuring a cooling of the
internal air. Some power sizes have a small secundary fan
close to the control card, ensuring that the internal air is
®
VLT AutomationDrive FC 301/FC 302 Design Guide, 0.25-75 kW
circulated to avoid hot spots. The main fan is controlled by
the internal temperature in the frequency converter and
the speed gradually increases along with temperature,
reducing noise and energy consumption when the need is
low, and ensuring maximum cooling when the need is
there. The fan control can be adapted via 14-52 Fan Control
to accommodate any application, also to protect against
negative effets of cooling in very cold climates. In case of
over-temperature inside the frequency converter, it derates
the switching frequency and –pattern, see
chapter 5.1.4 Manual Derating for more info.
Minimum and maximum ambient temperature limits are
specified for all frequency converters. Avoiding extreme
ambient temperatures prolongs the life of the equipment
and maximizes overall system reliability. Follow the
recommendations listed for maximum performance and
equipment longevity.
•
•
•
•
•
•
•

5.1.4 Manual Derating

Consider derating when any of the following conditions
are present.
•
•
•
•
MG33BF02 - Rev. 2013-12-20
Although frequency converters can operate at
temperatures down to -10 °C, proper operation at
rated load is only guaranteed at 0 °C or higher.
Do not exceed the maximum temperature limit.
Do not exceed the maximum 24h average
temperatue.
(The 24h average temperature is the max.
ambient temperature minus 5 °C.
Example: Max. temperature is 50 °C, maximum
24h avg. temperature is 45 °C )
Observe the minimum top and bottom clearance
requirements (chapter 8.2.1.1 Clearance).
As a rule of thumb, the lifetime of electronic
components decreases by 50% for every 10 C
when operated above its design temperature.
Even devices with high protection ratings must
adhere to the specified ambient temperature
ranges.
Additional air conditioning of the cabinet or
installation site may be required.
Operating above 1000 m (low air pressure)
Low speed operation
Long motor cables
Cables with a large cross section
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