2-124 Output Current
Output Current [Output Current]
This parameter displays the total output current of the drive. The current
value displayed here is the vector sum of both torque producing and flux
producing current components.
Output Devices Drive Output Contactor
Also see Input Devices on page 2-108.
Cable Termination
Voltage doubling at motor terminals, known as reflected wave phenomenon,
standing wave or transmission line effect, can occur when using drives with
long motor cables.
Inverter duty motors with phase-to-phase insulation ratings of 1200 volts or
higher should be used to minimize effects of reflected wave on motor insu-
lation life.
Applications with non-inverter duty motors or any motor with exceptionally
long leads may require an output filter or cable terminator. A filter or termi-
nator will help limit reflection to the motor, to levels which are less than the
motor insulation rating.
Cable length restrictions for unterminated cables are discussed on
page 2-51
. Remember that the voltage doubling phenomenon occurs at dif-
ferent lengths for different drive ratings. If your installation requires longer
motor cable lengths, a reactor or cable terminator is recommended.
Optional Output Reactor
Bulletin 1321 Reactors can be used for drive input and output. These
reactors are specifically constructed to accommodate IGBT inverter appli-
cations with switching frequencies up to 20 kHz. They have a UL approved
dielectric strength of 4000 volts, opposed to a normal rating of 2500 volts.
The first two and last two turns of each coil are triple insulated to guard
!
ATTENTION: To guard against drive damage when using output
contactors, the following information must be read and
understood. One or more output contactors may be installed
between the drive and motor(s) for the purpose of disconnecting or
isolating certain motors/loads. If a contactor is opened while the
drive is operating, power will be removed from the respective
motor, but the drive will continue to produce voltage at the output
terminals. In addition, reconnecting a motor to an active drive (by
closing the contactor) could produce excessive current that may
cause the drive to fault. If any of these conditions are determined to
be undesirable or unsafe, an auxiliary contact on the output
contactor should be wired to a drive digital input that is
programmed as “Enable.” This will cause the drive to execute a
coast-to-stop (cease output) whenever an output contactor is
opened.
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