Technical information

3
3
•
Wh
en measur
i
n
g
t
h
e outer
b
u
lb
temperature,
c
orrespon
di
n
g
eva
l
uat
i
on must cons
id
er t
h
e
radiation
(
cooling-down curve
)
The radiation o
f
the arc tube heats up the thermo-
couple on the outer bulb above the temperature o
f
the
quartz
g
lass on which it is positioned. Because o
f
the
l
ow t
h
erma
l
capac
i
t
y
, t
h
e t
h
ermocoup
l
e coo
l
s
d
own
quickly to the temperature o
f
the quartz glass, a
f
ter
switchin
g
o
ff
the lamp, and then cools down slowly
w
i
t
h
t
h
e quartz, as s
h
own
i
n
Fig
. 36 an
d
Fig
. 37.
Th
e
f
lat part o
f
the coolin
g
curve can be extrapolated back
to the switch-o
ff
p
oint to ascertain the tem
p
erature o
f
t
h
e outer
b
u
lb
d
ur
i
n
g
operat
i
on
.
The
m
easu
r
e
m
e
nt m
us
t
be
m
ade
u
n
de
r w
o
r
s
t
case
conditions, i.e.
f
or the pinch temperature: base up
burnin
g
position,
f
or the outer bulb temperature:
horizontal burnin
g
position
(
if permitted
).
7.1.
3
M
easur
i
n
g
po
i
nts
f
or t
h
ermocoup
l
es
i
n
diff
erent
l
amp type
s
T
he speci
f
ic limit values are stated in the Technical
In
fo
rm
a
ti
o
n
.
The
m
easu
r
ed
v
alues
a
r
e
t
o
be
asce
rt
ai
n
ed
u
n
de
r t
he
w
o
r
s
t
case
co
n
d
iti
o
n
s.
Both supply volta
g
e and choke impedance in
f
luence
l
amp watta
g
e.
A
l
ower c
h
o
k
e
i
mpe
d
ance an
d
high
e
r
supp
l
y vo
l
ta
g
e eac
h
cause an
i
ncrease
i
n
l
amp watt-
a
g
e.
A
s t
h
e
li
m
i
t temperatures a
l
so
i
ncrease w
i
t
h
i
n-
creas
i
ng
l
amp wattage, t
h
e worst case
i
s to
b
e ascer-
ta
i
ne
d
at t
h
e max
i
mum poss
ibl
e
l
amp watta
g
e.
T
o cov
-
er a
ll
poss
ibl
e parameters suc
h
as c
h
o
k
e
i
mpe
d
ance,
spread o
f
lamp watta
g
e and supply volta
g
e tolerance.
Lamp watta
g
e should be set to approximately 20
%
above the normal watta
g
e
f
or measurement purposes
.
T
he operatin
g
temperatures o
f
a lamp di
ff
er accordin
g
to t
h
e
b
urn
i
n
g
pos
i
t
i
on.
Th
e worst case operat
i
on
i
s
the base up burnin
g
position
f
or pinch or base ed
g
e
temperature measurements an
d
t
h
e
h
or
i
zonta
l
b
urn
i
n
g
p
osition
f
or the outer bulb tem
p
erature measurement,
inso
f
ar as this is possible with the permitted burnin
g
pos
i
t
i
ons
.
T
em
p
erature measurement
l
am
p
s
p
re
p
are
d
w
i
t
h
t
h
er-
m
ocou
p
les are available from
OS
RAM on re
q
uest for
a
f
ee
.
cooling time in s
measured temperature in °C
500
400
300
200
100
0
0
50
100 150
200
250 300
350
T
m1
temperature read when switching o
ff
, includes additional heating up o
f
the thermocouple b
y
radiatio
n
T
m2
extrapolated temperature of the quartz
g
lass when switchin
g
of
f
Fi
g
. 36:
C
oolin
g
curve for H
C
I-T 150 W
/
830 PB in
c
l
ose
d
l
um
i
na
i
re,
l
amp wattage 180
W
°C
sec
530
520
510
500
490
480
470
460
450
440
430
420
410
400
390
380
0
5
10 15
20
25
30
35
Fi
g
. 37: Enlar
g
ed detail o
f
f
i
g
ure 36
C
om
p
liance with the outer bulb tem
p
erature is not
alwa
y
s sufficient to desi
g
n a “
g
ood” luminaire
.
T
m1
temperature read when switchin
g
off, includes additional heatin
g
up o
f
t
h
e t
h
ermocoup
l
e
by
ra
di
at
i
o
n
T
m2
e
xtrapolated temperature o
f
the quartz
g
lass when switchin
g
o
ff