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dg&rtV8b3fad,
l./hen
load
is
appi
iecl
to
an
alternator
already carryinci an
rnilial
load,
the
voltage drop
is less.
A
"passive" initialloa<j
,
e.g.
resistive
load
such
as
lighting,
rcactor
s transfon|er.
re..luces
the voltage
c1ro1r
so
slightly that jt is
posslble
to
uork
vr.i
th
tlre
sarne
values as
for
the
un-!oaded
alternator.
"Active"
loads
such
as
synchronous flrotors
and inducl.ion
nrotors,
o
the other
hancl
,
can
absorl-r
parl
of
the
shocl(
load
bec.ruse
of their field
enerqy,
Lhe dflrount
depending
on
their
size
and
c
h
a r'
,r
c
t
e
r
i
s
t
i
c
s
,
and thus can reduco
l-he vol
ta
qe
d
rop
condicierably.
Depending
on
its
nra!Jnitude,
the
sudden vol
laqe drop
is
restored v/ithin
a
few
cyc'l
es.
l,J
ithin
the
range
fro r
no-'load
to
full-load
the
st.able
v0lt
ge
values
Iie
vrithirt lhe
given,toleranr:e
band.
Average
values
of
volta!le
drop
vrhen
.load
js
sudden
applied
to
an
unloaded
al
ternator.
1'5
Sz(
?
0
S^,
=
l{a
ted
a
I
te|rr.l
l-or"
outl'u
L
Lo VDI f/i
"
(co1u',rn
I of
tlre Selection
tables
I
f
the
al
ternator output
t
s
!il
ven
VDE
output nust
still
be used
as
Srr=
Load appl
i
ecl assulrr'in!
s
tabl
e
a,l
terna
Lor
vo.l
tage
U..,-U
U
=
-ii-
x
100
(I)
(voltaqe drop
relaled
to
ral-ed voltage)
"N
U, =
Rated
alternator
voltage
=
l4ininunr
alternator
voit-aqc
af 1.er
load
appl
ic,rtion
th
4
0oC
co0
lant
tenpe ra lu
re
,
see
catalollue SIT
1)
to
colunrn
2
or
column
3
tlte
1.he
reference
va
I
ue.
For
al
ternators
450 Y/60llz
(4,
6
and ti-po1es)
frou
the
diagranr
is
to
be
urul
t.iplicd
by
i.1
The
tirne taken
to
restore the
vol
tage cdn
be
by
nreans
0f
the followinq
forrtlula and tables
the
value
of A
U
l:aken
deterrrjned
appr0xinraie ly
:
-3
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