Output Current 2-101
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 Disconnection
Allen-Bradley Drives can be used with an output contactor between the
drive and motor. This contactor can be opened under load without damage
to the drive. It is recommended, however, that the drive have a programmed
“Enable” input and that this input be opened at the same time as the output
contactor.
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 2-31. 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
against insulation breakdown resulting from high dv/dt. When using motor
line reactors, it is recommended that the drive PWM frequency be set to its
lowest value to minimize losses in the reactors.
!
ATTENTION: Any disconnecting means wired to the drive
output terminals U, V and W must be capable of disabling the
drive if opened during drive operation. If opened during drive
operation, the drive will continue to produce output voltage
between U, V, W. An auxiliary contact must be used to
simultaneously disable the drive.
To Next Page
Loading...
Need help?
General
