DOC-0017-03-EN: AC15 Series - Hardware Installation Manual
DOC-0017-03-EN-B 04.04.2023 97 (125)
Issues arising from long Motor Cable runs
Because cable capacitance and hence conducted emissions increase with motor cable length,
conformance to EMC limits is only guaranteed up to a maximum cable length as specified in the table in the
‘Cabling Requirement’ section above.
Screened/armoured cable has significant capacitance between the conductors and screen, which increases
linearly with cable length - typically 200pF/m, though this varies with cable type and current rating.
Long cable lengths may have the following undesirable effects:
- Inverter ‘overcurrent’ trip events as the cable capacitance is charged and discharged at the
switching frequency.
- Increased conducted emissions that degrade the performance of the internal EMC filter due to
common mode choke saturation.
- Increased heating inside the internal EMC filter (as a consequence of a saturated common mode
choke).
- RCD (Residual Current Devices) trips, due to increased high frequency earth current.
These effects can be overcome by adding the following:
- External EMC Filter (Input or Output), located as close as possible to the inverter
- AC Line Chokes
- AC Motor Chokes
Refer to ‘Chapter 7: Associated Equipment’ for recommended Associated Equipment.
For RCD trips, internal Y-Capacitor and Overvoltage Suppressors to earth connections can be removed by
means of a link disconnect. Refer to ‘Chapter 6: Installation’ for details on how to disconnect them from
earth.
To Next Page
Loading...
Need help?
General
