IDEALARC DC-600
E-2
THEORY OF OPERATION
INPUT LINE VOLTAGE, CONTAC-
TOR AND MAIN TRANSFORMER
The desired three phase input power is connected to
the DC-600 through an Input Contactor located in the
input box at the rear of the machine. Two phases of
the input line are also connected to the Control
Transformer which supplies power to the Contactor
Hold-In Circuit. The Contactor Hold-In Circuit will dis-
able the Input Contactor if the DC-600 is overloaded or
overheated.
A Reconnect Panel allows the user to configure the
machine for the desired input voltage. This AC input
voltage is applied to the primary of the Main
Transformer. The transformer changes the high volt-
age, low current input power to a low voltage, high cur-
rent output. The finishes or "neutrals" of the main sec-
ondary coils are connected together and the six starts
of the secondary windings are connected to the rectifi-
er assembly. In addition the main transformer also has
an isolated 115VAC auxiliary winding that supplies
115VAC to operate the cooling fan and offers 8 amps
of auxiliary power to operate wire feeding equipment.
The three 75VAC phase angle windings are also
housed in the Main Transformer assembly. These
windings provide power and "timing" to the firing board.
TERMINAL
STRIP
CONTACTOR
TO
CONTROL
BOARD
REMOTE
CONTROL
MAIN
TRANSFORMER
CONTROL
TRANSFORMER
115 VAC
115 VAC
FAULT PROTECTION
PROTECTION
DEVICES &
CIRCUTS
CONTACTOR
HOLD-IN
(
)
FIRING BOARD
CONTROL
BOARD
PILOT
RELAY
F
E
E
D
B
A
C
K
F
E
E
D
B
A
C
K
OUTPUT
CONTROL
MODE
SWITCH
POSITIVE
TERMINAL
NEGATIVE
TERMINAL
LATCHING
RESISTOR
PILOT
RELAY
CHOKE
1
1
5
V
A
C
FAN
R
E
C
O
N
N
E
C
T
SCR BRIDGE
SHUNT
FIGURE E.2 Input Line Voltage, Contactor and Main Transformer
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
8/98