Ground Connections - Control Techniques Commander SE Guide D'utilisation

Ground connections

The drive must be connected to the system ground of the AC supply. The ground wiring
must conform to local regulations and codes of practice.
The ground loop impedance must conform to the requirements of local safety
regulations. The ground connections must be inspected and tested at appropriate
intervals.
WARNING
Earth and ground leakage
Commander SE sizes 1 to 4
There is no direct connection with ground apart from the surge protection on the input of
the drive. The ground leakage is therefore negligible (<1µA).
Commander SE size 5
Due to a capacitor between -DC and ground, the ground leakage current is typically
9mA at 380 to 415V 50Hz AC supply; up to 14mA at 480V 60Hz AC supply. A fixed
ground connection must be made before the AC power is applied. In some applications,
safety regulations require a duplicate ground connection. Measured by the method
described in IEC950 Annex D.
The RFI filter has a higher leakage current, data is given in section 4.5.4, Tables
4.15 to 4.19. When the standard and low cost filters are used, a permanent fixed
ground connection must be provided which does not pass through a connector
WARNING
or flexible power cord.
Motor cables
For routine EMC precautions
Use either of the following:
• Cables containing three power conductors plus a ground conductor
• Three separate power conductors plus a ground conductor
For full EMC precautions, where required (see section 4.5.2 Full EMC
precautions on page 33)
Use shielded (screened) or steel-wire armoured cable having three power conductors
plus a ground conductor.
If the cable between the drive and the motor is to be interrupted by a contactor or
circuit breaker, ensure that the drive is disabled before the contactor or circuit
breaker is opened or closed. Severe arcing may occur if this circuit is interrupted
WARNING
with the motor running at high current and low speed.
Maximum motor cable lengths
The capacitive loading of the drive by the motor cable means that the cable length limits
shown in Table 4.3 must be observed. Failure to do so can result in spurious OI.AC
tripping of the drive. If longer cable lengths are required, consult your local Drive Centre
or Distributor.
Drive size
1
2
3
4
5 (400V)
5 (480V)
Table 4.3 Maximum motor cable lengths
* This cable length is for 3kHz switching frequency. The cable length reduces in
proportion to the switching frequency; e.g. at 6kHz, it is reduced by a factor of 2 to 60m.
30
Maximum motor cable length
Meters Feet
75 246
100 330
150 495
150 495
200* 660*
124* 410*
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Commander SE User Guide
Issue Number 9