Environmental conditions, How it works, Cascaded “h” bridge (chb) topology – Rockwell Automation 6012DB PowerFlex Medium Voltage Variable Frequency Drive User Manual
Page 10: Environmental conditions how it works
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Rockwell Automation Publication 6000-UM001B-EN-P - October 2014
Chapter 1
Introduction
Refer to national and local safety guidelines for detailed procedures on how to
safely isolate the equipment from hazards.
Environmental Conditions
•
Elevation above sea level must be less than 1000 m (3250 ft)
(1)
.
•
Ambient air temperature must be between 0...40°C (32...104°F)
(2)
.
•
Relative humidity must be less than 90%, non-condensing.
•
The drive must be installed indoors; there must be no dripping water or
other fluids in the room.
•
Cooling air must be clean without significant concentrations of sand,
corrosive or conductive dust (defined by IEC 721-1 as being less than
0.2 mg/m
of dust), or explosive gas.
•
Free from significant vibration.
•
The drive must be anchored on a level floor. Please refer to the dimension
drawing for the anchor point sizes and locations.
For the equipment to operate in conditions other than those specified, consult
the local Rockwell Automation Sales Office.
How it Works
Cascaded “H” Bridge (CHB) Topology
The proven CHB topology combines an integrally mounted phase shifting
isolation transformer and series-connected power modules for each phase. In
addition to stepping down the input voltage, the isolation transformer also
provides two other principal functions:
•
Mitigate common mode voltage stress so motors with standard insulation
levels can be used.
•
Reduce Total Harmonic Distortion (THD), due to the phase shifting of
its secondary windings, so input side harmonics don’t negatively impact
the plant or utility power grid.
ATTENTION: The national and local electrical codes outline provisions for safely
installing and working on electrical equipment. Installation must comply with
specifications regarding wire type, conductor sizes, branch circuit protection
and disconnect devices. Failure to do so may result in personal injury and/or
equipment damage.
(1) Options are available for operation up to 3000 m.a.s.l. However, these must be stated at the time of order and cannot be retrofitted
in the field.
(2) Options are available for ambient temperatures up to 50 ºC. However, these must be stated at the time of order and cannot be
retrofitted in the field.