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Section 7
Non-bypass Component Functions
Power Fusing
For all option panel power fuses, use the specified
fuse or an equivalent replacement only. See the
fuse ratings label on the inside cover of the unit for
option panel fuse ratings.
Main fusing.
Main fuses are located ahead of the
drive and bypass. Main fuses are designed to
protect the circuitry within the bypass panel but is
not adequate to protect the drive. Main fuses are
dual-element, time-delay types and mount inside
the bypass enclosure.
Drive fusing.
Drive fuses are located ahead of the
drive and are a fast-acting type. Drive fuses are
standard in two-contactor and three-contactor
bypasses. A fuse/disconnect enclosure may be
used if no options other than a fuse block and
disconnect switch are required.
100,000 amp SCCR.
The option panel is at least
5,000 amps short-circuit current rating (SCCR). An
additional 100,000 amp SCCR is available as an
option. See the panel label for SCCR rating.
Reactors
Input line reactor.
This is a 3-phase reactor,
mounted on the input to the option panel This low-
pass reactor adds 3% impedance on the line input.
The impedance filters noise from the line input to
the drive along with the return drive noise on the
line. It is not in operation when running across the
line.
Output dV/dt filter.
This is a 3-phase reactor-
capacitor-resistor combination. Mounted in series
with the output of the drive, it functions to reduce the
magnitude of voltage spikes related to PWM wave
forms generated by the drive. It allows the use of
longer motor leads and reduces insulation stress on
motors without interphase insulation. It is not
connected to the motor when running across the line.
Disconnects
Main disconnect.
The main discon-
nect removes line input power to the
drive and option panel. A main discon-
nect is available in four options.
•
Fused disconnect.
Two-position
(ON/OFF) rotary switch, padlock
compatible, with three fuses, one
on each phase, built into the
switch. For safety, the switch must
be in the OFF position before the
option panel door can be opened
or fuses removed.
•
Disconnect with fuses
. Two-
position (ON/OFF) rotary switch,
padlock compatible, with a fuse
block mounted separately from the
disconnect. Three fuses, one on
each phase, are located on the fuse
block. For safety, the switch must be
in the OFF position before the
option panel door can be opened.
•
Main circuit breaker.
A thermal/
magnetic current interrupt device
using an ON/TRIP/OFF/RESET
switch. When in the ON position, a
high current fault removes power
from the drive/option panel circuit
and the switch moves to the TRIP
setting. It must be moved to the
RESET position momentarily after
the fault has been cleared to reset
the circuit breaker.
•
Disconnect without fuses
. For
user-supplied fuses option.
Drive disconnect.
Two-position (ON/
OFF) rotary switch disconnects main
AC line input power to the drive only.
