THEORY OF OPERATION
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Section TOC
INPUT |
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SWITCH | RECTIFIER |
| AIR |
| PRESSURE |
| SWITCH |
| "A" |
POWER BOARD
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| IGBT |
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| CAPACITOR |
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| IGBT |
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MAIN
TRANSFORMER
TRIGGER & SAFETY
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| WORK | |
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| NOZZLE | |
| ELECTRODE |
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| TORCH | |
OUTPUT | BOARD | CONNECTOR | |
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| CHOKE | S | |
| PILOT | O | |
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TRANSISTOR | |||
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| TRIGGER & SAFETY | ||
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| AIR | |
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| SOLENOID | |
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| REMOTE | |
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| INTERFACE | |
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| RECEPTACLE | |
Return to Master TOC
Return to Master TOC
L |
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A |
D |
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| SIGNAL |
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| N | SIGNAL |
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| R | A | T | S | |
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| E | I | H | A | |
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| R | E | F | ||
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| THERMOSTATS |
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| W | L |
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OUTPUT
CONTROL
DISPLAY BOARD
ELECTRODE & TRANSFER
CURRENT FEEDBACK
PILOT ENABLE
ELECTRODE SOLENOID ENABLE
AIR SOLENOID ENABLE
12VAC
24VAC
Section TOC
Master TOC
115VAC
AUXILIARY
TRANSFORMER FAN MOTOR
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to Section TOC
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to Master TOC
PRECHARGE AND PROTECTION
The input voltage is rectified by the input rectifier. The resultant DC voltage is applied, through the reconnect switch, to the power board. The power board contains precharging circuitry for the safe charging of the input filter capacitors. Once the capacitors are precharged and balanced the control board activates the CR1+ CR2 input relays. This connects full input power to the filter capacitors. When the filter capacitors are fully charged they act as power supplies for the IGBT switching circuit. The Insulated Gate Bipolar Tran- sistors supply the main transformer primary winding with DC current flow. See IGBT Operation discussion and diagrams in this section.
The power board also monitors the filter capacitors for voltage balance and under or overvoltage. If either should occur, the appropriate signal is sent to the con- trol board to deactivate the CR1+ CR2 input relay. The machine output will also be disabled.
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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
