ESAB Precision Plasmarc EPP-450 Manual De Instrucciones página 56

section 6
6.6 auxiliary main contactor (k3 & k33) and solid state contactor circuits
K3 and K33, activated by supplying a Contactor Signal, initiate and controls the operation of K2 (Starting Contactor) and
K4 (Pilot Arc Contactor). K3/K33 are called the Auxiliary Main Contactors because they must be activated before the
Main Contactor (K1) power-up sequence can occur. The Contactor Signal is supplied through a remote contact connect-
ing 115VAC from J1-R to J1-M. If K6 is closed (no fault), K3 will activate. The closing of K3(6, 9) activates K2, the Starting
Contactor, and K4, the Pilot Arc Contactor, provided the power source is not over heated. See Subsection 6.7, E-stop and
Main Contactor Circuits for more information on the operation of K2. K4 is turned off when the Current Detector senses arc
current and opens the contact connecting P2-5 to P2-6 on the Control PC Board.
In addition to operating K3/K33, the Contactor Signal also activates the Solid State Contactor. The Solid State Contactor is
a logic and interlock circuit permitting the IGBT's to conduct whenever the remote Contactor Signal is present. The 115V
AC Contactor Signal is fed to TB1-9, TB7-8, and resistors R45 and R45A. These resistors reduce the 115V to approximately
16V AC fed into the Control PC Board at P6-1 and P6-2. The Control PC Board sends a signal to both the Left and Right PWM
/ Gate Drive PC Boards. Illumination of LED3 on both of the PWM / Gate Drive PC Boards is indication that the Solid State
Contactor is functioning.
AUXILLARY MAIN CONTACTOR (K3 & K33) & SOLID STATE CONTACTOR CIRCUITS
TB7-8
K3 K7
6 9 6 9
Over Heat Relay - Closed
during normal operation
3
FN4 4
1 2
TB1-7
115V
AC
J1-R
J1-Z
H N
CONTACTOR SIGNAL CONTACTOR SIGNAL
115V AC
PILOT ARC
CONTACTOR
P2-5
K4
Current Detector
Contact on
Control PCB
K33 K15
6
K2
STARTING
CONTACTOR
J1-H
TB8-7
TB1-8
K6
Fault Relay
J1-M
9
I
P2-6
TB9-16
TB9-13
TB9-18
6 9
P6-2
K3 K33
(AMC)
TB1-9
6
Open with fault or
main line power off
56
troubleshootinG
LEFT PWM/GATE RIGHT PWM/GATE
DRIVE PC BOARD DRIVE PC BOARD
IGBT DRIVE IGBT DRIVE
ON/OFF ON/OFF
LED3
P1-9 P1-10 P1-9 P1-10
+15V
Solid State Contactor
680
CONTROL
PC BOARD
P6-1
TB7-9
R45A
10K 10K
8W
TB7-8
LED3
T
R45B
8W