Tweco 300 XT Auto-Cut 380V - Manual (Page 120)

AUTO-CUT 300 XT
A-3� APPENDIX Manual 0-5261
APPENDIX 18: ADVANCED TROUBLESHOOTING
System Overview
The Auto-Cut 200 & 300 XT & Ultra-Cut 100, 200, 300 & 400
XT power supplies include one, two or three inverter mod-
ules (IM). Each IM may have either 1 or 2 inverter sections
designated A or B sections. The IMs are mounted one over
the other numbered from bottom to top. The sections are
also designated from bottom to top with section A being on
the bottom of each module. An IM with one section is con-
sidered to be a ½ or “partial” module with the upper or “B”
section missing. ½ modules are used with the 200A & 300A
power supplies and will always be in the middle position.
IMs with 2 sections are considered to be “full” modules.
Each inverter section can supply up to 67A but does not do
so in all configurations:
A 400A unit uses 6 sections. 400A / 6 = 66.67A per section.
A 300A unit uses 5 sections. 300A / 5 = 60A per section.
A 200A unit uses 3 sections. 200/3 = 66.67A per section.
A 100A unit uses 2 sections. 100/2=50A per section.
Unit configurations.
With the exception of the AC 200 XT all other units have the
same chassis with room for up to 3 IMs. The unused areas
have blank panels filling the empty locations which are
required for proper air flow. A 100A system uses 1 full IM;
200A uses 1 and ½ modules with a full module in the bottom
location and a ½ module in the middle position. A 300A
unit has full modules top and bottom with the ½ module
in the middle location. The AC 200 XT has only the bottom
and middle locations for IMs. An internal Arc Starter and
Gas Control are located in the place of the 3rd or upper IM.
Inverter module cooling.
The power semiconductors of the inverter modules are liq-
uid cooled allowing us to get more power in a smaller area
and at lower cost. Each IM has a liquid cooled heatsink or
“cold plate” shared by the 2 inverter sections. The magnetic
components, transformers and inductors, are air cooled and
mounted on the back side of the IMs where they are exposed
to high volumes of air flow from the cooling fans whose air
also cools liquid coolant in the radiator or heat exchanger.
It is important that lower right side panel be in place or the
air flow will not be proper for cooling the magnetics.
Inverter control.
The inverter sections are operated as separate inverters
whose outputs are connected in parallel. They are controlled
independently from the Command and Control Module
(CCM) which is the “brains” of the system. Each inverter
section has a separate ribbon cable connected to it coming
from the CCM which has 6 connectors, J31 – J36 correspond-
ing to the inverter sections 1A through 3B. The ribbon cables
are labeled on the inverter ends as INV with the number and
Art # 12299
Art # 12300