Delta VFD-ED Series User Manual

Appendix A. EMC Standard Installation GuideVFD-ED
A-14
Criteria for Earthing System and EMC
TN-S TN-C TT IT
Safety of
Personnel
Good Good Good Good
Continuity of the
PE conductor
must be ensured
throughout the
installation
Continuity of the
PE conductor
must be ensured
throughout the
installation
RCD is mandatory Continuity of the
PE conductor
must be ensured
throughout the
installation
Safety of
Property
Poor Poor Good Good
High fault current
(around 1kA)
High fault current
(around 1kA)
Medium fault
current (< a few
dozen amperes)
Low current at the
first fault (< a few
dozen mA) but
high current at the
second fault
Availability of
Energy
Good Good Good Excellent
EMC Behavior
Excellent Poor (prohibited) Good Poor (should be
avoided)
• Almost
equipotential
Problems:
• Need to handle
the high
leaking
currents
problem of the
device
• High fault
current
(transient
disturbances)
• Neutral and PE
are the same
• Circulation of
disturbance
currents in
exposed
conductive
parts (high
magnetic-field
radiation)
• High fault
currents
(transient
disturbances)
• Over-voltage
risk
• Equipotential
Problems:
• Need to handle
the high
leaking
currents
problem of the
device
• RCD
(Residual-
current device)
• Over-voltage
risk
• Common–
mode filters
and surge
arrestors must
handle the
phase-to-phase
voltage.
• RCDs subject
to nuisance
tripping when
common-mode
capacitors are
present
• Equivalent to
TN system for
second fault

Delta VFD-ED Series Specifications

General

Brand	Delta
Model	VFD-ED Series
Category	DC Drives
Language	English