Aggressive Environments - Danfoss VLT AutomationDrive FC 300 Design Manual

Safety and Conformity
with oil-resistant gaskets to mount oil-tight or dust-tight
mechanisms. Doors are also provided with oil-resistant
gaskets. In addition, enclosures for combination controllers
2 2
have hinged doors, which swing horizontally and require a
tool to open.
UL type validates that the enclosures meet NEMA
standards. The construction and testing requirements for
enclosures are provided in NEMA Standards Publication
250-2003 and UL 50, Eleventh Edition.
IP Codes
Table 2.4 provides a cross-reference between the 2
standards. Table 2.3 demonstrates how to read the IP
number code and defines the levels of protection. The
frequency converters meet the requirements of both.
NEMA type
Chassis
Protected chassis
NEMA 1
NEMA 12
Table 2.3 IP Number Cross Reference
First digit (solid foreign objects)
0 No protection
1 Protected to 50 mm (hands)
2 Protected to 12.5 mm (fingers)
3 Protected to 2.5 mm (tools)
4 Protected to 1.0 mm (wire)
5 Protected against dust – limited entry
6 Protected totally against dust
Second digit (water)
0 No protection
1 Protected from vertical dripping water
2 Protected from dripping water at 15° angle
3 Protected from water at 60° angle
4 Protected from splashing water
5 Protected from water jets
6 Protected from strong water jets
7 Protected from temporary immersion
8 Protected from permanent immersion
Table 2.4 IP Number Code Definitions

2.5 Aggressive Environments

A frequency converter contains a large number of
mechanical and electronic components, many of which are
vulnerable to environmental effects.
16
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VLT AutomationDrive FC 300 Design Guide 90-1200 kW
CAUTION
The frequency converter should not be installed in
environments with airborne liquids, particles, or gases
capable of affecting and damaging the electronic
components. Failure to take the necessary protective
measures increases the risk of stoppages, thus reducing
the life of the frequency converter.
Degree of protection as per IEC 60529
To prevent cross faults and short circuits between
terminals, connectors, tracks, and safety-related circuitry
caused by foreign objects, the Safe Torque Off (STO)
function must be installed and operated in an IP54 or
higher rated control cabinet (or equivalent environment).
IP type
Liquids can be carried through the air and condense in the
IP00
frequency converter and may cause corrosion of
IP20
components and metal parts. Steam, oil, and salt water
IP21
may cause corrosion of components and metal parts. In
IP54
such environments, use equipment with enclosure rating IP
54/55. As an extra protection, coated printed circuit boards
can be ordered as an option.
Airborne particles such as dust may cause mechanical,
electrical, or thermal failure in the frequency converter. A
typical indicator of excessive levels of airborne particles is
dust particles around the frequency converter fan. In very
dusty environments, use equipment with enclosure rating
IP54/IP55 or a cabinet for IP00/IP20/TYPE 1 equipment.
In environments with high temperatures and humidity,
corrosive gases such as sulphur, nitrogen, and chlorine
compounds will cause chemical reactions on the frequency
converter components.
Such chemical reactions will rapidly affect and damage the
electronic components. In such environments, mount the
equipment in a cabinet with fresh air ventilation, keeping
aggressive gases away from the frequency converter.
Optional coated PCBs also offer protection in such
environments.
NOTICE
Mounting frequency converters in aggressive
environments increases the risk of stoppages and consid-
erably reduces the life of the converter.
Before installing the frequency converter, check the
ambient air for liquids, particles, and gases. This is done by
observing existing installations in this environment. Typical
indicators of harmful airborne liquids are water or oil on
metal parts, or corrosion of metal parts.
Excessive dust particle levels are often found on instal-
lation cabinets and existing electrical installations. One
MG34S202 - Rev. 2013-08-19