ESAB Precision Plasmarc EPP-600, Instruction Manual, Page: 29 / 90

29
sectIon 4 operatIon
4.1 Block Diagram circuit Description
Le
ft P
W
M / G
ate D
riv
e B
oa
rd
G
al
va
ni
c
I
so
la
to
r
PW
M
G
ate
D
riv
e
G
al
va
ni
c
Is
ol
ato
r
PW
M
G
ate
D
riv
e
(M
as
te
r)
(S
la
ve
)
Ri
gh
t P
W
M / G
ate D
riv
e B
oa
rd
2
H
Sy
nc S
ig
na
l
Fo
r A
lte
rn
ate
Sw
itc
hi
ng
3 P
ha
se
In
pu
t
T1 M
ai
n
Tr
ans
fo
rm
er
-3
00
V-
37
5V
D
C B
us
Bu
s R
ec
tifi
er
s
30
0U
12
0’
s
Ca
p.
Ba
nk
Co
nt
ro
l C
irc
ui
t
Fe
ed
ba
ck F
or F
as
t I
nn
er S
er
vo
s
Er
ro
r A
m
pl
ifi
er
s
G
al
va
ni
c
I
so
la
to
r
0.
0 - 1
0.
0V D
C V
re
f
Io
ut = (
Vr
ef
) x (
80
)
CN
C C
om
m
on
(F
lo
at
in
g)
S
T
“T
” C
om
m
on C
on
ne
cte
d to E
ar
th G
ro
un
de
d W
or
k T
hr
ou
gh t
he “
+” O
ut
pu
t
Fe
ed
ba
ck f
or C
ons
ta
nt
Cu
rr
en
t S
er
vo
Tw
is
te
d P
ai
r
Le
ft
IG
BT M
od
ul
es
Se
e N
ote
Ri
gh
t
IG
BT M
od
ul
es
T
Le
ft H
al
l
Se
ns
or
Ri
gh
t H
al
l
Se
ns
or
L1
Bl
oc
ki
ng D
io
de
s
Bl
oc
ki
ng D
io
de
s
L2
Fr
ee W
he
el
in
g
D
io
de
s - S
ee N
ote
T
T1
T1
Co
nt
ac
t o
n P
ilo
t
A
rc C
on
ta
cto
r
42
5V P
ea
k
25
0V P
ea
k
Bo
os
t S
ta
rt
in
g
Ci
rc
ui
t
Bi
as
ed S
nu
bb
er
R (
bo
os
t)
R (
sn
ub
)
Pi
lo
t A
rc
Ci
rc
ui
t
Pr
ec
is
io
n
Sh
un
t
EL
EC
TR
O
D
E
N
O
ZZL
E
W
O
RK
EP
P-
60
0
BL
O
CK D
IA
G
RA
M
Se
e
N
ote
Se
e N
ote
n
ot
e
Bo
th t
he I
G
BT
’s a
nd F
re
e W
he
el
in
g D
io
de
s a
re
co
nt
ai
ne
d i
n t
he s
am
e m
od
ul
e.