AMD2000 Series - Servo Drive - User Manual
50
DS619-0-00-0019 - Rev 0
ANCA Motion
Cable routing
6.8.12.3
In a drive system the return common mode currents flow through shields, cabinets, gear tray
and earth wiring to create localized parasitic ground potentials, which may affect control signals
using the ground as a common voltage reference. Careful planning of cable routing and
location of shield grounds must be done to minimise influence of parasitic ground potentials,
and ensure compliance with EMC requirements. The following guidelines must be followed.
Physically separate “noisy” and “clean” cables at the planning stage. Pay special attention
to the motor cable. The area around the shared terminal strip for the mains input and
motor output is particularly at risk.
All cable routing in an enclosure should be as mounted close as possible to gear tray or
grounded cabinet walls;
“free-floating cables” act as both active and passive antennae
Use twisted pair wires wherever possible to prevent interference from radiated common
mode noise sources. Continue the twist as close as possible to terminals.
Use shielded twisted pairs for analogue and control level wires exiting from the overall
enclosure.
Keep power and control wiring separate. Crossing at right angles is permitted, but no
significant parallel runs should be allowed, and cables should not share cable trays,
trunking or conduits unless they are separately shielded and the shields correctly
terminated
Avoid mixing pairs with different signal types e.g., 110 V AC, 230 V AC, 24 V DC,
analogue, digital.
Run wires along the metal surface and avoid wires hanging in free air, which can become
an antenna.
If plastic trunking/ducting is used, secure it directly to installation plates or the framework.
Do not allow spans over free air which could form an antenna.
Keep shield pigtails as short as possible and note they are less effective than full clamping
Allow no breaks in the cable shields.
Earthing connections should be as short as possible in flat strip, multi-stranded or braided
flexible conductors for low RFI impedance.
When an EMC enclosure is to be used, the maximum diagonal or diameter for any hole is
100 mm, which equates to 1/10th of the wavelength of a 300 MHz frequency. Holes bigger
than 100 mm must be covered with a metal frame surrounding the aperture and earthed to
the enclosure.
6.9
Drive Output Filters
6.9.11
Sinusoidal Filter
Sine-wave filters are designed to let only low frequencies pass. High frequencies are consequently shunted away
which results in a sinusoidal phase to phase voltage waveform and sinusoidal current waveforms. Sine wave
filters are recommended for the following applications:
Reduction of motor acoustic switching noise
Motors that are not “inverter rated” which have reduced insulation levels and can only accept
sinusoidal inputs supplies
Retrofit installations with old motors that are not “inverter rated”
Motors that require reduced bearing currents to prolong motor life and reduce service intervals
Step up applications or other applications where the frequency converter feeds a transformer
Note: Sine-wave filters must be selected for the drive switching frequency of 8kHz. Sinusoidal filters with nominal
frequency higher than 8kHz cannot be used.
Standard Sinewave filters are connected to the drive output as shown in
Figure 6-14
. For more demanding
applications, Sinewave filters with DC bus connections can also be used as shown in
Figure 6-15
. There is an
output voltage drop of approximately 5-10% across the sinusoid filter.
Recommended Sinusoidal filters
AMD2000, 3A, with no DC bus connection
Schaffner 3-phase 4A Sinewave and
EMC Filter FN 520-4-29
