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THEORY OF OPERATION
FIGURE E.4 – SWITCH BOARDS
S | FET | B | |
W | O | ||
I | CAP | A | |
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LINE | INPUT |
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| CHARGE | ||||
SWITCH | RECTIFIER |
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| CHARGE | ||
FAN |
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| P B | S |
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TRANS |
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115 |
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VAC | 2 | C |
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TRANS |
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| LESS THAN 1VDC |
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T4 |
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| PULSE TRANSFORMER SIGNAL | ||||||
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RPWM SIGNAL
M
O
S15VDC
T
A |
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T | GUN TRIGGER | CONTROL BOARD |
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36VAC
TAILOUT | PEAK | BACK- | PEAK | HOT | BACK- | WIRE | |
CURRENT | GROUND | SIZE | |||||
CONTROL | CURRENT | START | GROUND | ||||
(STT II ONLY) | METER | METER | CONTROL CONTROL CONTROL | SWITCH | |||
CURRENT
TRANS
T3
WIRE
TYPE
SWITCH
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| OUTPUT |
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| TERMINAL |
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MAIN | 1 OHM |
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TRANSFORMER |
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T2 |
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CURRENT | IGBT | NEGATIVE |
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SENSOR | MODULE | OUTPUT |
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| TERMINAL |
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CHOKE |
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| VOLTAGE |
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| SENSING |
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| RECEPTACLE | |
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| D | O |
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| REMOTE | |
| I | E | B | |
| V |
| CONTROL | |
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| RECEPTACLE | |
| E | P | O | |
| S | R | A |
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| N | D |
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| WIRE |
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| FEEDER |
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| RECEPTACLE |
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CURRENT FEEDBACK
IGBT
DRIVER
BOARD
VOLTAGE FEEDBACK
10VAC AND 6VAC
42VAC
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SWITCH BOARDS
There are two switch boards in the Invertec STT, each containing an input filter capacitor. The capacitors are connected in parallel when the machine is connected for "low" input voltage. The capacitors are connected in series when the reconnect switch is configured for "high" input voltage. When the capacitors are fully charged, they act as power supplies for the switch boards. The switch boards contain the Field Effect Transistors (FETs) which, when switched on, supply the main transformer primary windings with DC current flow. See Field Effect Transistor (FET) Operation discussion and diagrams. See Figure E.4.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
