Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 162)

ULTRA-CUT 400 XT
A-5� APPENDIX Manual 0-5275
Group 2 – Plasma Power Supply codes
General:
LEDS
Several LEDs are used as indicators on the different inverter module boards. RED LEDs indicate faults. Green LEDs should
be on for the most part. Green LEDs are: On the main board, D�-READY; On the Cap Bias Board, D�, -12V, D11 +12VP (pri-
mary referenced), D13, +12V; On the Control board D2�, PWM will only be on when the inverter is enabled and its brightness
varies with the duty cycle of the PWM.
Signals:
General description of some Inverter Signals passed to the CCM that can generate fault codes in Group 2.
“Ready” also called AC IN FLT (D�, READY LED, green, on Main Inverter board)
On the inverter main board we measure the input voltage. The 3 phases are rectified and lightly filtered to achieve an average
voltage. Due to the light filtering a missing phase will also lower the average voltage so it will be detected. Voltage in the
correct range turns on the READY LED D� (on the far left of the main boards, in the upper part of the “B” section or lower
part of the “A” section). Voltage outside the correct range or missing phase will turn D� off.
An AC Input Fault by itself (no other faults occurring at the same time) will set codes in the 2�1-2�� group depending on
which inverter sees the problem.
INV FLT (D1, INV FLT LED, red, on the Inverter Control and Fault board)
Several things can cause Inv Flt (Inverter Fault). Inverter fault is indicated by an LED, D1 on the Inverter Control and Fault
board. Inverter Fault, when it occurs, is latched on. The latch is reset next time the inverter is enabled unless it is still active
in which case it is immediately latched again. Inverter Fault will set the codes 2�7-252 unless it’s in conjunction with another
fault in which case that fault code may be set.
Things that can set the inverter fault:
• The local (to the inverter) + 12V & -12V bias supplies out of tolerance. There are LEDs on the Cap/Bias board that
light indicating these bias supplies are present but don’t verify they are in tolerance. It’s not likely this would happen.
More likely that fault related to the +/-12V the supply would be missing and it’s LED not on.
• Capacitor imbalance. In a cap imbalance condition D3, red Led on the main board (lower left corner of bottom or “A”
section and upper left corner of the upper or “B” section), will latch on.
• Primary over current. This is an over current condition in main switching transformer’s primary. This will latch on
but is cleared when the inverter is enabled unless it is still active in which case it is immediately latched again.
• Inverter over temperature sets the Fault signal and LED but has its own fault signal to the CCM. See OT Flt below.
OT FLT (D1�, OT FLT, Inverter Control and Fault board)
• Inverter over temperature lights LED D14 on the Inverter Control and Fault board and will latch the fault signal and it’s
LED but also has its own separate fault so that will be reported as a code in the range of 253-25� or 259-2��.
PWR Present
• When power is first applied to the inverter (contactor closed) CCM checks for presence of the +12V bias on the Inverter
Control and Fault board. If not present will set codes in the range of 2�5-270.
IS_ID (A, B, or C)
VAC_SEL (A or B)
201 Missing AC Phase
The System Bias Supply board contains circuits to detect if one of the 3 AC input phases is missing. Along with that it can
also detect if the AC voltage is too low or too high. Three phase voltage is supplied from the input terminals through the ON/
OFF Switch / circuit breaker CB1 to the System Bias board. The System Bias can operate on any 2 of the 3 phases to supply
control power and fault detection.