Aggressive environments
In common with all electronic equipment, a frequency
converter contains a large number of mechanical and
electronic components, all of which are vulnerable to
environmental effects to some extent.
The frequency converter should not there-
fore be installed in environments with air-
borne liquids, particles or gases capable
of affecting and damaging the electronic
components. Failure to take the necessa-
ry protective measures increases the risk
of stoppages, thus reducing the life of the
frequency converter.
Liquids can be carried through the air and condense
in the frequency converter. In addition to this, liquids
may cause corrosion of components and metal parts.
Steam, oil and salt water may cause corrosion of com-
ponents and metal parts.
In such environments, equipment with enclosure rat-
ing IP 54 is recommended.
Airborne
particles such as dust particles may cause
mechanical, electrical or thermal failure in the frequen-
cy converter.
A typical indicator of excessive levels of airborne par-
ticles is dust particles around the frequency converter
fan.
In very dusty environments, equipment with enclosure
rating IP 54 or a cabinet for IP 00/20 equipment is rec-
ommended.
In environments with high temperatures and humidity,
corrosive gases such as sulphur, nitrogen and chlor-
ine compounds will cause chemical processes on the
frequency converter components. Such chemical re-
actions will rapidly affect and damage the electronic
components.
In such environments, it is recommended that equip-
ment is mounted in a cabinet with fresh air ventilation,
keeping aggressive gases away from the frequency
converter.
NB!
Mounting frequency converters in aggres-
sive environments will increase the risk of
stop-pages and furthermore considerably
reduce the life of the converter.
Before the installation of the frequency converter, the
ambient air should be checked for liquids, particles and
gases. This may be done by observing existing instal-
lations 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 in-
stallation cabinets and existing electrical installations.
One indicator of aggressive airborne gases is black-
ening of copper rails and cable ends on existing in-
stallations.
Calculation of resulting reference
The calculation made below gives the resulting refer-
ence when parameter 210 Reference type is program-
med for Sum [0] and Relative [1], respectively.
External reference is the sum of references from ter-
minals 53, 54, 60 and serial communication. The sum
of these can never exceed parameter 205 Max. refer-
ence.
External reference can be calculated as follows:
Ext. ref. =
(Par. 205Max. ref . - Par. 204 Min. ref.) x Ana. signal Term. 53 [V] +
+
(Par. 205 Max. ref. - Par. 204 Min. ref.) x Ana. signal Term. 54 [V]
+
Par. 310 Term. 53 Max. scaling - Par. 309 Term. 53 Min. scaling Par. 313 Term. 54 Max. scaling - Par. 312 Term. 54 Min. scaling
(Par. 205 Max. ref. - Par. 204 Min. ref.) x Par. 314 Term. 60 [mA]
+
serial com. reference x (Par. 205 Max. ref. - Par. 204 Min. ref.)
Par. 316 Term. 60 Max. scaling - Par. 315 Term. 60 Min. scaling 16384 (4000 Hex)
Par. 210 Reference type is programmed = Sum [0].
Ext. ref. =
(Par. 205 Max. ref. - Par. 204 Min. ref.) x Par. 211-214 Preset ref.
+
External ref. + Par. 204 Min. ref . + Par. 418/419 Setpoint (only in closed
loop)
100
Par. 210 Reference type is programmed = Relative [1].
Res. ref. =
External reference x Par. 211-214 Preset ref.
+
Par. 204 Min. ref. + Par. 418/419 Setpoint (only in closed loop)
100
VLT
®
6000 HVAC Series
194 MG.61.B5.02 - VLT
®
is a registered Danfoss trademark
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