User manual
47
4 - CONNECTIONS
When selecting shielded cable for use as motor leads, it is important to select a cable which is
designed for operation at the frequencies and power levels involved. Improper selection of motor
cable can cause high potential to exist on the shield. This could cause damage to the inverter and other
equipment, and could pose a safety hazard.
The following cables are acceptable for this purpose: OLFlex Series 150CY, 110CY, 110CS, 100CY, •
100CS, and 540CP. Siemens CordaexSM is also acceptable. Some of these cables are VDE-approved
only; others carry VDE, UL, CSA, and combinations of these ratings. Be sure to conrm that the cable
you are using meets the certication of the agency required.
OLFlex cables are available from OLFlex Wire & Cable, 30 Plymouth Street, Faireld NJ 07004,
(800)-774-3539.
Cordaex cables are available from Siemens Energy and Automation, Inc., Power Cables, 3333
State Bridge Road, Atlanta GA 30202, (800)-777-3539.
If the installation requires the use of an output reactor then the reactor, like the line lter, should be •
placed as close as possible to the inverter. Control wires longer than 3 feet (1 meter) must be run in
shielded cable, and the shield must be terminated at circuit common (Acom) on the inverter. Note
that connection to (Dcom) rather than earth ground is allowed because RSi S4 inverters have isolated
control inputs. If the signal run exceeds 30 feet (9 meters), a 0-20 mA or 4-20 mA signal should be
used, as it will have better noise immunity than a low level voltage.
Other loads connected to the power source may produce voltage transients (spikes) that may interfere •
with or damage the inverter. Line reactors or lters can be used on the input power to protect the
inverter from such transients.
If the inverter is operated from switchgear devices or is in close proximity to switchgear devices (in a •
common cabinet), the following procedures are recommended as a precaution to prevent these devices
from interfering with the inverter’s operation:
Wire the coils of DC devices with freewheeling diodes. The diodes should be placed as close as •
possible to the physical coil of the device.
Wire the coils of AC devices with RC type snubber networks. Place the snubbers as close as •
possible to the physical coil of the device.
Use shielded cables on all control and monitoring signals. •
Route distribution cables (for example, power and contactor circuits) separately and as far away
from control and monitoring signal cables as possible.