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Praesideo 3.5 | Installation and User Instructions | 4 | Amplifiers
8.8.12 Derating
The graph shows the available continuous power used
for emergency tones, speech, etc. as function of the
ambient temperature.
55
50
45
40
35
30
25
20
25
30
35
figure 8.20: Output power derating
If the amplifier is loaded with loudspeakers up to its
rated output power (see section 8.8.12), you can still
play music and speech for an indefinite long period of
time at an ambient temperature of 55 °C, because of the
crest factor (or peak-to-average ratio) of the audio
signals. The crest factor of music and speech is typically
6 to 8 dB, which makes the required continuous power
25% or less of the rated output power. Alarm tones are
set to -3 dB maximum by Praesideo, resulting in a
required continuous power of 50% of the rated output
power. This can be delivered for at least 30 minutes at
55 °C ambient or continuously at 30 °C ambient.
Bosch Security Systems | 2011-02
40
45
50
55
T (°C)
8.8.13 Control inputs
Connector (rear side):
16 pole header (type Phoenix MC1,5/16-G-3,81) for
removable screw connector (MC1,5/16-SWT-3,81)
Total cable resistance:
< 1 kohm (with line supervision)
< 5 kohm (without line supervision)
Resistance detection (supervision enabled):
Cable short circuit
< 2.5 kohm
Contact closed
7.5 kohm to12 kohm
Contact open
17.5 kohm to 22 kohm
Cable broken
60
> 27 kohm
Resistance detection (supervision disabled):
Contact closed
< 12 kohm
Contact open
> 17.5 kohm
External contacts:
Voltage-free closing or breaking contacts (relay
contacts, mechanical switches, mercury contacts
etc.)
en | 155
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