Tweco 15XC Merlin - Manual (Page 104)

CUSTOMER/OPERATOR SERVICE 5-32 Manual 0-2251
5.12 SERVICE AND TEST PROCEDURES (continued)
J. Main Contactor Circuit
(W1 and W2)
Only one of the two main contactors (W1 and W2) is used
at any given time. The K5 relay on the voltage selection
PC board selects which contactor is activated. If the red
LED indicator (D18) on the voltage selection board is lit,
W2 is selected. If D18 is not lit, W1 is selected.
There are three ways to initiate main contactor closure.
Two are through the remote jack (J15). J15-14 is a momen-
tary closure where a push-button (remote START switch)
or CNC device momentarily (100 ms) connects J15-14 to
the logic board common (J15-15).
The second is a maintained closure where a CNC device or
the remote pendant connects J15-24 to the logic board
common (J15-25) and maintains the connection until the
contactor is opened.
The third is a maintained closure from J14-4 to logic com-
mon (J14-3) used for hand torch control. The momentary
stop input (J15-16) used in conjunction with momentary
start, disables all start inputs when connected to logic
common (J15-17). The CNC station select function uses
this input to prevent starting when the station is not
selected.
Only one start switch may be activated at any given time,
but any stop signal will stop the unit. For example, with
the remote panel and a hand torch connected, if the unit is
started with the hand torch switch, it may be stopped with
the remote stop switch. Once stopped, it cannot be re-
started with the remote start switch until the hand torch
switch is released. When the system is started by the
remote start switch, pressing and releasing the hand torch
switch will stop it.
The start signal activates the red ‘start’ LED indicator
(D57) on the logic PC board to indicate that the start signal
was received by the logic board. D57 stays lit until the
stop signal is received.
The start signal initiates the gas pre-flow, which is nor-
mally two seconds but may also be set for other time
periods (see Section 4.5, Plasma Cutting Operation). After
pre-flow is complete the K2 relay on the logic board closes,
sending 120 VAC from J2-1 out through J2-12 on wire #23
to J6-5 on the voltage selection PC board and through the
K5 relay to one of the main contactors.