25 Commander SE User Guide
www.controltechniques.com Issue Number 8
The ground loop impedance must conform to the requirements of local safety
regulations. The ground connections must be inspected and tested at appropriate
intervals.
Earth and ground leakage
Sizes 1 ~ 4
The drive has a very small leakage current between the power lines and ground, which
is of no consequence.
Size 5
Ground leakage current is typically 9mA*. A fixed ground connection must be made
before the AC power is applied. In some applications, safety regulations require a
duplicate ground connection.
*9mA at 380Vac ~ 415V 50Hz AC supply. 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
4.13 to 4.17. When the standard and low cost filters are used, a permanent fixed
ground connection must be provided which does not pass through a connector
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)
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
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 4.2 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.
The maximum cable lengths were measured using cable with capacitance of 412pF/m.
Table 4.2 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.
High Capacitance Cables
Most cables have an insulating jacket between the cores and the armour or shield;
these cables have a low capacitance and are recommended. Cables that do not have
WARNING
WARNING
WARNING
Drive Size Maximum motor cable length
Meters Feet
1 75 246
2 100 330
3 150 495
4 150 495
5 120* 394*
To Next Page
Loading...
Need help?
General
