BENSHAW M2L 3000, Руководство пользователя

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4 – Theory of Operation
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IGBT Cell (18)
AC Midpoint (3)
Converter
Connections
Motor
Connections
I/O Rack
Card Rack
Hub Controller
Cooling Blowers
Figure 12: Typical 1500 hp Inverter – Front View with Covers Removed
Figure 12 represents a typical small frame, 1500 hp, 18 Cell Inverter with the front co-
vers removed. IGBT cells can be seen as 3 vertical columns in the right side of the en-
closure. The leftmost vertical column, located closest to the center of the enclosure, is
Phase A followed by Phases B and C. The AC midpoint of each phase is located behind
the grey panels covering the AC terminals and inductive filters.
Internal cabling routes the AC outputs from the phases to the Input/Output section of the
Inverter, in the area located in the lower left of the enclosure. Also shown in this section
are components associated with the pre-charge function and current loop power for the
IGBT cells.
The Input/Output section of the enclosure is the area where power connections are
made to the Inverter. AC output cables from the motor are attached to landing pads on
the right side of the Input/Output section, while high voltage cables that interconnect the
Converter and Inverter are attached to landing pads on the left side. The enclosure al-
lows for top or bottom entry of both AC and DC cables.
The Inverter is forced-air cooled. Air is drawn through filters on the front of the enclosure
by blowers mounted on the top. The Inverter is designed to function with only 3 of the 4
blowers operating at any given time, providing redundancy and high operating availabil-
ity. Two filter elements are provided in series on the front of the enclosure to block the
ingress of dirt and dust particles. The filter assembly mounts over a protective screen,
welded to the enclosure, that prevents inadvertent contact with the resident high volt-
ages when the filter media is removed for cleaning or replacement.
The compartmental nature of the Inverter’s internal design provides baffling to route air
flow through critical areas of the enclosure. The standard Inverter enclosure is rated for
NEMA 1 applications.
For testing and checkout purposes, the Inverter is designed with a power supply system
that enables control power to be applied without medium voltage main power being ap-
plied.
.