14
“Power+” +0500048IE - rel 2.2 - 06.11.2014
ENG
Earth leakage current
As for all inverter devices, earth leakage current may occur greater than 3,5mA. The drive is designed to produce the
minimum possible leakage current. The current depends on the length and the type of motor cable, the eff ective
switching frequency, the type of earth connection used and the type of RFI fi lter installed.
Important:
When earth leakage current is greater than 3,5mA the protective conductor should be at least 10mm
2
if copper or
16mm
2
if aluminium. As an alternative an additional protective conductor could be used.
If a residual-current circuit breaker (RCCB) is to be used, the following conditions apply:
• it must be a type B device (suitable to protect the equipment against leakage current with a DC component);
• Individual RCCBs should be used for each drive.
Motor
Connect the motor power cable: use four-wire cable, the impedance of the earth wire must be less than or equal to
the impedance of the phase wires. For the size and maximum length of the cable according to the model, see the
table in paragraph 5.1. To ensure conformity to the EMC directive, use shielded cable with tape + braid shields (SN/
ST). The cable can also be laid in steel and copper cableways.
U
V
W
PE
MOTOR CABLE
Schermo treccia
Braid shield
Schermo nastro
Tape shield
Fig. 3.j
Earth the shield with 360° a metal clamp on both ends of the cable, as close as possible to the terminals. In case of
connection of the shield to the drive earth terminal (not recommended), the shield has to be twisted. The twisted
part must be left as short as possible, and the length must not exceed fi ve times the width. Earth the motor directly
using the drive earth terminal .
It is recommended to use a ferrite cable core (e.g. Fair-Rite 2631102002) rounding U, V, W wires only, located between
shield earthing and the drive terminals.
To Next Page
Loading...
