Rockwell Automation 1336 8A-48A Fiber Industry - Manual (Page 14)

2–6 Installation/Wiring
Immunity
The immunity of 1336 PLUS drives to externally generated
interference is good. Usually, no special precautions are required
beyond the installation practices provided in this publication.
It is recommended that the coils of DC energized contactors
associated with drives be suppressed with a diode or similar device,
since they can generate severe electrical transients.
Emission
Careful attention must be given to the arrangement of power and
ground connections to the drive to avoid interference with nearby
sensitive equipment. The cable to the motor carries switched
voltages and should be routed well away from sensitive equipment.
The ground conductor of the motor cable should be connected to the
drive ground (PE) terminal directly. Connecting this ground
conductor to a cabinet ground point or ground bus bar may cause
high frequency current to circulate in the ground system of the
enclosure. The motor end of this ground conductor must be solidly
connected to the motor case ground.
Shielded or armored cable may be used to guard against radiated
emissions from the motor cable. The shield or armor should be
connected to the drive ground (PE) terminal and the motor ground as
outlined above.
Common mode chokes at the drive output can help reduce common
mode noise on installations that do not use shielded cable. Common
mode chokes can also be used on analog or communication cables.
Refer to page 2–29 for further information.
An RFI filter can be used and in most situations provides an effective
reduction of RFI emissions that may be conducted into the main
supply lines.
If the installation combines a drive with sensitive devices or circuits,
it is recommended that the lowest possible drive PWM carrier
frequency be programmed.
Electrical Interference –
EMI/RFI