Technical information

2
0
4.1.3 Superimposed ignito
r
I
n a super
i
mpose
d
ig
n
i
t
i
on un
i
t, t
h
e
high
vo
l
ta
g
e
i
s
onl
y
present at the lamp outputs o
f
the unit. Depend
-
in
g
on cable and structure, i
g
nition units o
f
this type
can normally take loads o
f
100 pF, correspondin
g
to
a lead len
g
th o
f
about 1.5 m
.
4.
2
W
arm re-
ig
n
i
t
i
o
n
N
orma
l
ig
n
i
t
i
on vo
l
ta
g
es
i
n t
h
e ran
g
e up to 5
kV
d
o
not permit immediate re-i
g
nition o
f
a lamp which is
st
ill
h
ot.
Th
e
high
operat
i
n
g
pressures
d
eman
d
ig
n
i
t
i
on
volta
g
es o
f
e.
g
. 25 kV. I
f
a lamp
g
oes out
f
or instance
because o
f
a brie
f
interruption in the supply volta
g
e, it
must cool down for a few minutes
(
for lamp watta
g
es
<
150 W
)
until the fallin
g
pressure in the arc tube per-
mits re-i
g
nition
f
or normal i
g
nition units in the 5k
V
ran
g
e.
High
er watta
g
e
l
eve
l
s requ
i
re cons
id
era
bl
y
longer cooling down periods because o
f
the highe
r
t
h
erma
l
capac
i
ty.
Th
e coo
li
n
g
d
own process
d
epen
d
s
a
l
so on t
h
e am
bi
ent temperature an
d
t
h
e
l
um
i
na
i
re.
A
narrow,
h
ot
l
um
i
na
i
re pro
l
on
g
s t
h
e coo
li
n
g
d
own pro-
cedure, delayin
g
re-i
g
nition o
f
the lamp
.
This cool down time must be considered
f
or ignition
un
i
ts w
i
t
h
a t
i
mer cut-out w
hi
c
h
are
d
es
ig
ne
d
to s
h
ut
o
ff
a
f
ter a certain period o
f
time with
f
ailed i
g
nition.
The desi
g
n intent assumes that the lamp is de
f
ective
or not
i
nserte
d
.
Th
e se
l
ecte
d
t
i
mer
p
er
i
o
d
must
b
e
su
ff
icient to allow the lamp enou
g
h time to cool down
f
ollowin
g
a power interruption so that lamp re-i
g
nition
is a
g
ain possible. The warm re-i
g
nition times o
f
the
P
O
WERBAL
L
®
are under 10 minutes
,
f
ar shorter than
those o
f
the c
y
lindrical version
.
4.
3
H
ot re-
ig
n
i
t
i
o
n
Hi
g
h i
g
nition volta
g
es o
f
16 to 60 kV are necessary
f
o
r
immediate re-i
g
nition of hot metal halide lamps
(
hot
re-i
g
nition
)
on account of the hi
g
h vapor pressures.
The lamp, sockets and luminaire must be desi
g
ned
f
o
r
these hi
g
h volta
g
es, and suitable i
g
nition units must
be used. There are two versions o
f
hot re-i
g
nition units
w
i
t
h
symmetr
i
ca
l
an
d
asymmetr
i
ca
l
i
gn
i
t
i
on pu
l
ses.
I
n
t
h
e as
y
mmetr
i
ca
l
un
i
ts, care must
b
e pa
id
to correct
polarit
y
o
f
the lamp connections
!
A
t present, hot re-i
g
nition is permitted
f
or double
-
ended
q
uartz lam
p
s
(
with a few exce
p
tions
)
. As far
as ceram
i
c
l
amps are concerne
d
, t
h
e s
i
n
gl
e-en
d
e
d
H
C
I
®
-TM series with
G
Y22 socket are approved for
h
ot re-i
g
nition. Approval o
f
other double-ended ce
-
ram
i
c
l
am
p
s
i
s
i
n
p
re
p
arat
i
on
.
4.4 Ignition at low ignition voltage
(
Penning effect
)
V
ar
i
ous met
h
o
d
s can
b
e use
d
to re
d
uce t
h
e vo
l
ta
g
e
n
ecessary to i
g
nite the lamp.
O
ne such method uses
the so-called Pennin
g
e
ff
ect. When the ener
g
y stored
in a meta-stable excitation level o
f
the basic
g
as is
lar
g
er than the ionization ener
g
y o
f
the admixture, vol-
u
me ionization be
g
ins at lower
f
ield stren
g
ths, result-
in
g
in a lar
g
er number o
f
char
g
e carriers at the same
volta
g
e than in pure
g
as. Examples
f
or the Pennin
g
e
ff
ect include mercury in ar
g
on
f
or metal halide lamps
and ar
g
on in neon
f
or some dischar
g
e lamps.
4.5
Ig
n
i
t
i
on at
l
ow am
bi
ent temperatures
M
ost meta
l
h
a
lid
e
l
amps w
i
t
h
watta
g
es
<
400
W
can be operated at ambient temperatures of – 50 °
C
.
Th
e usua
lly
evacuate
d
outer
b
u
lb
an
d
t
h
e
l
um
i
na
i
re
ensure t
h
at t
h
e arc tu
b
e
i
s t
h
erma
lly
d
ecoup
l
e
d
f
rom the surroundings, so that the normal operating
p
arameters are achieved as
f
ar as
p
ossible. For
H
QI
®
2000
W
NI
an
d
2000
W
DI
,
ig
n
i
t
i
on
i
s on
l
y
permitted to – 20 °
C.
In the i
g
nition units, the
f
errite core is sensitive to tem-
perature, that is, the rated ignition voltage is lower at
lower temperatures.
S
ome i
g
nition unit manufacturers
recommend the use o
f
i
g
nition units without cut-out,
as the
f
errite core in this case is heated up b
y
the loss-
es durin
g
f
ailed i
g
nition attempts so that the speci
f
ied
i
g
nition pulse levels are reached a
g
ain. There are also
i
g
nition units with an additional inte
g
rated resistor
f
o
r
h
eat
i
n
g
t
h
e
ig
n
i
t
i
on un
i
t so t
h
at t
h
ese are approve
d
for temperatures down to – 50 °
C
. Here a
g
ain, it takes
a while a
f
ter switchin
g
the i
g
nition unit on until it has
heated up enou
g
h to reach the speci
f
ied i
g
nition pulse
l
e
v
e
l
s.
For speci
f
ic applications such as in cold stora
g
e hous-
es, semi-parallel i
g
nition units can be used
(
which per-
mit lon
g
er lead len
g
ths
)
that are fitted in warmer zones
ou
t
s
i
de
th
e
l
u
min
a
ir
es.
S
Luminaire
Lamp
U
choke
Capacitor for
PFC
Superimposed
ignition unit
Fi
g
. 21:
S
implified circuit dia
g
ram for conventional
operation o
f
hi
g
h intensit
y
dischar
g
e lamps with a
s
uper
i
mpose
d
ig
n
i
t
i
on un
i
t
Th
e t
i
mer per
i
o
d
f
or
ig
n
i
t
i
on un
i
ts w
i
t
h
warm
re-
i
gn
i
t
i
on must
b
e appropr
i
ate
l
y
l
ong enoug
h
.