Air Humidity; Aggressive Environments - Danfoss VLT Series Design Manual

2. Introduction to the VLT HVAC Drive

2.3. Air humidity

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The adjustable frequency drive has been designed to meet the IEC/EN 60068-2-3 standard, EN
50178 pkt. 9.4.2.2 at 122° F [50° C].

2.4. Aggressive Environments

An adjustable frequency drive contains a large number of mechanical and electronic components.
All are vulnerable to environmental effects to some extent.
Liquids can be carried through the air and condense in the adjustable frequency drive and may
cause corrosion of components and metal parts. Steam, oil and salt water may cause corrosion
of components and metal parts. In such environments, use equipment with enclosure rating IP
55. As an extra protection, coated printet circuit boards can be ordered as an option.
Airborne particles such as dust may cause mechanical, electrical or thermal failure in the adjustable
frequency drive. A typical indicator of excessive levels of airborne particles is the presence of dust
particles around the adjustable frequency drive fan. In very dusty environments, use equipment
with enclosure rating IP 55 or a cabinet for IP 00/IP 20/TYPE 1 equipment.
In environments with high temperatures and humidity, corrosive gases such as sulfur, nitrogen
and chlorine compounds will cause chemical processes on the adjustable frequency drive com-
ponents.
Such chemical reactions will rapidly affect and damage the electronic components. In such envi-
ronments, mount the equipment in a cabinet with fresh air ventilation, keeping aggressive gases
away from the adjustable frequency drive.
An extra protection in such areas is a coating of the printed circuit boards, which can be ordered
as an option.
Before installing the adjustable frequency drive, check the ambient air for liquids, particles and
gases. This is done by observing existing installations in this environment. A typical indicator of
harmful airborne liquids is the presence of water or oil on metal parts, or the corrosion of metal
parts.
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The adjustable frequency drive should not be installed in environments with airborne
liquids, particles or gases capable of affecting and damaging the electronic compo-
nents. Failure to take the necessary protective measures increases the risk of
stoppages, thus reducing the life of the adjustable frequency drive.
NOTE
Mounting adjustable frequency drives in aggressive environments increases the risk
of stoppages and considerably reduces the life of the drive.
MG.11.B4.22 - VLT ® is a registered Danfoss trademark.
VLT ® HVAC Drive Design Guide