Bosch Appliances 3.5 manual Derating, Control inputs, 20: Output power derating

Praesideo 3.5 Installation and User Instructions 4 Amplifiers

en 155

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
Power	Power)	45
		40
Output	Output
		35
Continuous	(% of Rated	30
		25
		20	30	35	40	45	50	55	60
		25
					T (°C)

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.

8.8.13 Control inputs

Connector (rear side):

16pole 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

7.5kohm to12 kohm Contact open

17.5kohm to 22 kohm Cable broken

> 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.)

Bosch Security Systems 2011-02