Protective Earth (Pe) Connection - Emerson PACMotion VFD Series User Manual

Protective Earth (PE) Connection

Grounding Guidelines
Adequate safety earthing must be provided in accordance with local wiring rules and codes of practice.
The ground terminal of each PACMotion VFD should be connected back to the common safety earth bar
to maintain touch potentials within safe limits. The ground terminal of each PACMotion VFD should be
individually connected DIRECTLY to the site ground bus bar (through the EMC filter if installed). PACMotion
VFD ground connections should not loop from one drive to another, or to, or from any other equipment.
Ground impedance must conform to local industrial safety regulations and/or electrical codes.
To meet UL regulations, UL approved ring crimp terminals should be used for all ground wiring connections.
The integrity of all ground connections should be checked periodically.
Protective Earth Conductor
The Cross sectional area of the PE Conductor must be at least equal to that of the incoming supply
conductors.
Motor Ground
The driven motor must be locally connected to a suitable ground location to maintain touch potentials within
safe limits. In addition, the motor ground must be connected to one of the ground terminals on the drive.
Ground Fault Monitoring
As with all inverters, a leakage current to earth can exist. The PACMotion VFD is designed to produce the
minimum possible leakage current whilst complying with worldwide standards. The level of current is
affected by motor cable length and type, the effective switching frequency, the earth connections used and
the type of RFI filter installed. If an ELCB (Earth Leakage Circuit Breaker) is to be used, the following conditions
apply:
• A Type B Device must be used.
• Individual device should be used for each PACMotion VFD.
• The device must be suitable for protecting equipment with a DC component in the leakage current.
• The device should be not sensitive to high frequency leakage current.
Shield Termination (Cable Screen)
The safety ground terminal provides a grounding point for the motor cable shield. The motor cable shield
connected to this terminal (drive end) should also be connected to the motor frame (motor end). Use a shield
terminating or EMI clamp to connect the shield to the safety ground terminal, refer to page 34.
GFK-3111A PACMotion VFD AC Variable Speed Drive User Guide 25