OSRAM POWERTRONIC PT-FIT I ECG for HID lamps, with cable clamp - Manual (Page 21)

THE PRODUCT IN OPERATION
21
Note:
As a rule of thumb, one may expect a doubling of service
life of POWERTRONIC
® devices where there is a long-
term reduction in the t
c
temperature of 10 °C. When the
ECG temperature exceeds the t
c
max limit, then the
POWERTRONIC ® protects itself through power
re duction or shutdown (see also 2.3.7.1).
At OSRAM the t
c
temperature has a direct relationship with
the service life of the ECG. In the case of the PT-FIT ECG
the maximum permissible temperature at the t
c
meter
point correlates to a life expectation of 30,000 h.
The t
c
temperature is thus an essential limit, for one thing
because of its importance for safety approval of luminaires
in accordance with EN 60598-1 and, for another, because
of its infl uence on the ECG's expected service life given by
the manufacturer due to the thermal load to which the
components are subjected.
2.3.6.6. Failure rate
The failure rate of electronic components depends not only
on the component specifi cation and quality, but also
strongly on the operating temperature. POWERTRONIC
®
devices are designed so that at the maximum permissible
device temperature (t
c
max.) a failure rate of fewer than
2.5 ‰ per 1000 hours of operation can be expected.
Given a service life of up to 60,000 hours (depending on
ECG type), this corresponds to a failure rate for devices of
less than 10 %. You can get more information on the failure
rate in the technical datasheets.
2.3.6.5. Effect of temperature on service life
The service life of an ECG is governed by the failure rate
of the electronic parts used within it. The failure rates of
these parts depend in turn on the particular properties of
their components and the thermal and electrical loads that
they are subjected to.
Extreme overheating can destroy components very
quickly. Long-lasting high temperatures can also lead to
premature failure. In some areas there may be an almost
exponential relationship between the failure rate of an elec -
tronic component and the thermal load it is subjected to.
Due to this exponential relationship, exceeding the per-
missible t
c
temperature can drastically reduce the service
life of an ECG. Conversely, where this temperature limit
is not reached, the service life of the device increases
disproportionately. The following graphics show the life
expectancy of the various types of ECGs at a variety of t
c
temperatures:
Figure 22: Life expectancy of PTi devices
Figure 23: Life expectancy of PTo 70/220-240 3DIM
Figure 24: Life expectancy of PTo 150/220-240 3DIM
0
0 20000 60000 100000 40000 80000 120000
10
20
40
30
50
60
80
70
90
100
Opera
tional devices read
y to use (%)
t (h)
T
a
= 40 °C/T
c
= 70 °C
T
a
= 45 °C/T
c
= 75 °C
T
a
= 50 °C/T
c
= 80 °C
T
a
= 55 °C/T
c
= 85 °C
100000
80
0 20000 60000 40000 80000 100000
85
90
95
100
105
Opera
tional devices read
y to use (%)
t (h)
T
a
= 40 °C/T
c
= 70 °C
T
a
= 45 °C/T
c
= 75 °C
T
a
= 50 °C/T
c
= 80 °C
T
a
= 55 °C/T
c
= 85 °C
0
0 20000 60000 100000 40000 80000 120000
10
20
40
30
50
60
80
70
90
100
Opera
tional devices read
y to use (%)
t (h)
T
a
= 40 °C/T
c
= 60 °C
T
a
= 45 °C/T
c
= 65 °C
T
a
= 50 °C/T
c
= 70 °C
T
a
= 55 °C/T
c
= 75 °C
PTi devices
PTo 70 3DIM
PTo 150 3DIM