Technical information

1
9
4 I
g
n
i
t
i
n
g
and start
i
n
g
d
i
schar
g
e lamp
s
S
ome dischar
g
e lamps do not require an external
i
g
nition unit, as the supply volta
g
e is su
ff
icient to
ignite the lamp or because the lamp has an integrated
ig
n
i
t
i
on un
i
t.
Th
ese
l
amps must n
ot
b
e use
d
i
n
i
nsta
ll
a
-
tions with an external i
g
nition unit or they will
f
ail pre
-
mature
l
y
d
ue to
i
nterna
l
arc
i
n
g.
All
ot
h
er
di
sc
h
ar
g
e
l
amps must
b
e
ig
n
i
te
d
b
y an a
ddi-
tional unit. Ignition units or circuits o
f
varying types are
used
f
or this purpose
.
A
t room temperature, the
f
illin
g
particles are still pres
-
ent in solid form
(
metal halides or amal
g
am
)
or in liquid
form
(
mercury
)
. The arc tube contains the start gas,
usua
ll
y an
i
nert
g
as suc
h
as ar
g
on or xenon,
b
etween
the electrodes. The insulatin
g
g
as
f
illin
g
in the arc
tu
b
e must
b
e ma
d
e con
d
uct
i
ve
i
n or
d
er to
g
enerate
h
ot p
l
asma.
Thi
s
i
s carr
i
e
d
out
b
y
high
-vo
l
ta
g
e pu
l
ses
g
enerate
d
b
y a separate
ig
n
i
t
i
on un
i
t or
b
y t
h
e
ig
n
i-
tion unit in an electronic ballast.
C
onstantl
y
available
free char
g
e carriers
(
electrons
)
are accelerated by hi
g
h
volta
g
e, providin
g
them with su
ff
icient ener
g
y to ionize
atoms on impact and
g
enerate more
f
ree char
g
e carri-
ers. This process, similar to an avalanche,
f
inall
y
pro
-
duces conductive hot
p
lasma within which the current
f
low excites the partly evaporated metal halide
f
illin
g
suc
h
t
h
at
ligh
t
i
s ra
di
ate
d.
Th
e
ig
n
i
t
i
on vo
l
ta
g
e requ
i
re
d
to
g
enerate a
b
rea
kd
own
between the electrodes depends on the spacing be
-
tween the electrodes, the
f
illin
g
pressure o
f
the
g
as
between the electrodes and the type o
f
g
as. Examples
f
or usin
g
these principles include the use o
f
auxiliary
electrodes or the use of Pennin
g
g
ases
(
see chapter
14.4
“I
g
nition at low i
g
nition volta
g
e
(
Pennin
g
effect
)
”
).
The sockets and cables must be suitably desi
g
ned
f
or
t
h
e
high
ig
n
i
t
i
on vo
l
ta
g
es.
I
n part
i
cu
l
ar w
i
t
h
t
h
e
E
27
sockets
f
or sin
g
le-ended screw base dischar
g
e lamps,
care must be taken that a similar socket
(
E27
)
for in
-
candescent lam
p
s is not used, which does not meet
t
h
e re
q
u
i
rements
.
When lamps are de
f
ective or no lamp is inserted,
continuous operation o
f
the i
g
nition unit can possibly
dama
g
e the i
g
nition unit or the luminaire. It is there
f
ore
advisable to switch the i
g
nition unit o
ff
f
or a period o
f
time a
f
ter
f
ailed i
g
nition, or to use an i
g
nition unit with
tim
e
r
fu
n
c
ti
o
n
.
4.1
E
xterna
l
ig
n
i
t
i
on un
i
t
s
4.1.1 Parallel ignition uni
t
Wi
t
h
a pu
l
se
ig
n
i
t
i
on un
i
t, t
h
e c
h
o
k
e must
b
e
i
nsu
l
ate
d
f
or its sur
g
es. The pulse i
g
nition units can normally
take a load o
f
1000 pF, permittin
g
lead len
g
ths o
f
about 15 m between lamp and choke. Durin
g
i
g
nition,
the lead carries hi
g
h volta
g
e
f
rom the choke to the
l
amp so t
h
at care must
b
e ta
k
en to ensure t
h
at t
h
e
supp
ly
l
ea
d
, soc
k
et an
d
l
um
i
na
i
re are a
d
equate
ly
i
n-
sulated
f
or the correspondin
g
hi
g
h i
g
nition volta
g
e.
T
his type o
f
i
g
nition unit is used in sin
g
le phase
g
rids
.
4.1.2
S
emi-parallel ignition unit
In the semi-parallel i
g
nition unit, part o
f
the choke
windin
g
s is used to trans
f
orm the i
g
nition pulses. This
m
eans the choke must be adequatel
y
insulated
f
or the
h
i
g
h volta
g
e and have a tap
f
or the i
g
nition unit. As
with pulse i
g
nition units, the i
g
nition unit can
g
ener-
ally take 1000 pF or approx. 15 m lead len
g
th, and
t
h
e connect
i
on
l
ea
d
b
etween c
h
o
k
e an
d
l
am
p
must
be insulated
f
or the correspondin
g
volta
g
e levels. A
capac
i
tor w
i
t
h
m
i
n
i
mum capac
i
tance
d
epen
di
n
g
on t
h
e
u
nit must be
p
rovided for com
p
liance with the EM
C
o
f
the i
g
nition unit
.
P
re
f
erence s
h
ou
ld
b
e
gi
ven to us
i
n
g
a t
i
me
r
i
g
nition unit
.
U
S
Luminaire
Lamp
U
choke
Capacitor for
PFC
Pulser
ignition unit
Fi
g
. 19:
S
implified circuit dia
g
ram for conventional
operation o
f
hi
g
h intensit
y
dischar
g
e lamps with pulse
ig
n
i
t
i
on un
it
S
Luminaire
Lamp
U
choke
Capacitor for
PFC
Semi-parallel
ignition unit
Fi
g
. 20:
S
implified circuit dia
g
ram for conventional
o
peration o
f
hi
g
h intensit
y
dischar
g
e lamps with a
s
em
i
-para
ll
e
l
ig
n
i
t
i
on un
i
t