Emc Installation Guidance; Protective Earth (Pe) Connections - Parker AC30P Hardware Installation Manual

EMC Installation Guidance

PROTECTIVE EARTH (PE) CONNECTIONS

Local wiring regulations take precedence and may require the protective earth connection of the motor to be connected locally, i.e. not
as specified in these instructions. This will not cause shielding problems because of the relatively high RF impedance of the local earth
Earthing
A star-point earthing policy separates 'noisy' and 'clean' earths. Four separate earth bus bars (three are insulated from the mounting panel)
connect to a single earth point (star point) near the incoming safety earth from the main supply:
1. Clean Earth Busbar (insulated from the mounting panel)
Used as a reference point for all signal and control cabling. This may be further subdivided into an analog and a digital reference busbar,
each separately connected to the star earthing point. The digital reference is also used for any 24V control.
Control/signal and encoder cables, all analogue inputs, and communications require screening with the screen connected only at the VSD
end. However, if high frequency noise is still a problem, earth the screen at the non-VSD end via a 0.1µF capacitor. Connect the screen (at
the VSD end) to the VSD protective earth point
2. Dirty Earth Busbar (insulated from the mounting panel)
Used for all power earths, i.e. protective earth connections. It is also used as a reference for any 110 or 220V control used, and for the
control transformer screen.
3. Metal Work Earth Busbar
The back panel is used as this earth busbar, and should provide earthing points for all parts of the cubicle including panels and doors. This
busbar is also used for power screened cables which terminate near to (10cm) or directly into a VSD- such as motor cables, braking
choppers and their resistors, or between VSDs - refer to the appropriate product manual to identify these. Use U-clips to clamp the
screened cables to the back panel to ensure optimum HF connection.
4. Signal/Control Screen Earth Busbar (insulated from the mounting panel)
Used for signal/control screened cables which do not go directly to the VSD. Place this busbar as close as possible to the point of cable
entry. 'U' clamp the screened cables to the busbar to ensure an optimum HF connection.
Flexible, large cross-section cable is used to ensure low HF impedance. Bus bars are arranged so that the connections to the single earth point is
as short as possible.
AC30 series Variable Speed Inverter
WARNING
connection.
and not to the control board terminals.
A-9
Compliance