Delta BLD-E1 brushless DC motor drive BLD-E1 Series - Manual (Page 13)

Chapter 1 Introduction|BLD-E1 Series
1-6 Revision May 2009, 00DE, V0.50
TN-S grounding system:
TN-S is a grounding system with 3-phase, 4-line and PE line. The feature of TN-S system is the
neutral line and protective earth(PE) line have an only common grounding at the neutral point of
transformer. The neutral line (N) is live part and PE line is NOT live part. This grounding system
equips safe and reliable basic potential.
L1
L2
L3
N
PE
L1 L2 L3
T N- S gr ounding system
TN-C grounding system:
TN-C grounding system is called 3-phase and 4-line system. This system combines the neutral
line with protective earthing(PE) and is called PEN line. This grounding system is sensitive to
the grounding malfunction with simple wiring but it is only suitable for the occasions with
balanced 3-phase overload. If the high harmonic current caused by the unbalanced current of
PEN line and other power electronic equipment superposes on the neutral line in the normal
situation and makes the neutral line to be live part with unstable current, it will cause unstable
neutral grounding potential. Moreover, it will also make the equipment case connected with
PEN line be live part to result in personal injury and incorrect accurate electronic equipment
operation (can’t get a suitable potential base point).
L1
L2
L3
PEN
L1 L2 L3
TN -C g roun ding s ys tem
TN-C-S grounding system:
TN-C-S grounding system is made up of two grounding systems, including TN-C system and
TN-S system. The connection point of these two systems is at the connection point of N line
and PE line.