GE Industrial Solutions EAK guidelines - Manual (Page 14)

GROUND CONNECTION OF THE ANALOG ZERO VOLT FOR OPTIONAL TBO CARD
The common references of the TBO analog signals (terminal 2 and 4) must be connected to terminal 11 of the
drive regulation board.
For the RS300 device the common reference of the analog output signals (terminal 22) must be connected to
terminal 11 of the device regulation board.
The minimum distance between parallel signals and power cables (supply cables of the motor is 30cm (12
inches). Possible crossings have to be made at 90”. In case of double cabinets (entry to the inside of the cabinet
on both sides with 2 different panels installed each other reverse side) it is advisable to have all signals cables
conveyed into ducts mounted on the inverter side (front) and to pass motor cables on the other side (back) trough
a hole made in the panel at the output of the inverter’s terminals.
In case of single cabinets, it is advisable to let the power cable run vertically, while those of signal horizontally,
keeping the maximum possible distance.
SHIELDING OF THE SUPPLY FOR AN AC MOTOR
The AC motors have to be supplied through a four pole shielded cable (three phases + green/yellow ground
wire), or through four unshielded cables, which are inserted inside a metal channel, consequently needing a
higher insulation (see relative safety standards). So, it is important that, further to the three phases, it has been a
direct connection (four cables) between the panel grounding and the motor and that the fourth cable had been
inserted in a shield.
GROUND CONNECTION TO BOTH SIDES OF THE CABLE SHIELD (AC MOTOR)
The shield of the supply cable of AC motors must be grounded on both sides in order to obtain a 360” contact,
that means the whole shield. This can be realized using suitable metallic EMC cables press grounded at 360” at
the input of the cabinet and of the motor’s terminal strip. If this connection is not possible, the shielded cables
should be brought inside the cabinet and connected with an omega connector (see figure) to the mounting panel.
The same must be done on the motor side: in case the connection at 360” on the motor’s terminal strip is not
possible, the shield must be grounded before entering into terminal strip, on the metal support of the motor,
using an omega connector (see figure). In case a metal duct has to be used, it should be both-sided grounded at
360” where possible.
PIGTAIL AVOIDING
While grounding the shielding of the cables, one has to adopt a 360” connection (E.g.: omega bus as in the table)
and the pigtail connection must be absolutely avoided. As pigtail here is meant the connection to earth of the
cable shield by means of a wire (or to use the same screen, roll it up and ground-connected).
SUPPLY CABLES OF THE DC MOTOR
The supply cables of DC motor do not need to be shielded.
D I R E C T C O N N E C T I O N B E T W E E N G R O U N D B U S A N D M O T O R C H A S S I S
Independently from any local ground-connection of the motor’s chassis, for safety reasons, it must always be
connected to the ground wire (yellow/green) coming from the panel ground bus.