Ac Power Draw And Thermal Dissipation; Power Draw, Current Draw And Thermal Dissipation - Crown Macro-Tech 5002VZ Reference Manual

Macro-Tech 5002VZ Power Amplifier
7 AC Power Draw and
Thermal Dissipation
This section provides detailed information about the
amount of power and current drawn from the AC power
line by the Macro-Tech 5002VZ, and the amount of heat
produced under various conditions. The calculations
presented here are intended to provide a realistic and
reliable depiction of the amplifier. The following assump-
tions were made:
• The amplifier's available channels are loaded, and full,
standard 1 kHz power is being delivered.
• Amplifier efficiency at standard 1kHz power is
estimated to be 73%.
• Quiescent power draw is 90 watts
• Quiescent heat dissipation equals 105 btu/hr at
90 watts.
• Duty cycle of pink noise is 50%.
• Duty cycle of highly compressed rock 'n' roll midrange
is 40%.
• Duty cycle of rock 'n' roll is 30%.
• Duty cycle of background music is 20%.
• Duty cycle of continuous speech is 10%.
• Duty cycle of infrequent, short-duration paging is 1%.
8 Ohm Stereo / 4 Ohm Parallel-Mono
AC Mains
Current Draw (Amps)
Power
Duty
Draw
Cycle
100-120 V 220-240 V
(Watts)
50% 1,881 22.7
40% 1,523 18.3
30% 1,164 14.0
20% 806 9.7
10% 448 5.4
Fig. 7.1 Power Draw, Current Draw and Thermal Dissipation at Various Duty Cycles
Reference Manual
4 Ohm Stereo / 8 Ohm Bridge-Mono / 2 Ohm Parallel-Mono 2 Ohm Stereo / 4 Ohm Bridge-Mono / 1 Ohm Parallel-Mono
AC Mains
Thermal Dissipation
Power
Draw
btu/hr kcal/hr
(Watts)
10.3 1,793 452 2,845
8.3 1,491 376 2,294
6.4 1,189 300 1,743
4.4 887 224 1,192
2.5 584 147 641
Here are the equations used to calculate the data pre-
sented in Figure 7.1:
The following equation converts power draw in watts to
current draw in amperes:
The value used for Power Factor is 0.83. The Power
Factor variable is needed to compensate for the differ-
ence in phase between the AC mains voltage and cur-
rent.
The following equation is used to calculate thermal dis-
sipation.
The value used for Amplifier Inefficiency is 0.27 (1.00–
0.73). The factor 3.415 converts watts to btu/hr. Ther-
mal dissipation in btu is divided by the constant 3.968
to get kcal.
If you plan to measure output power under real-world
conditions, the following equation may also be helpful:
Macro-Tech 5002VZ
L O A D
Current Draw (Amps) Thermal Dissipation
100-120 V 220-240 V btu/hr kcal/hr
34.3 15.6 2,606 657
27.6 12.6 2,142 540
21.0 9.5 1,677 423
14.4 6.5 1,212 305
7.7 3.4 748 189
AC Mains
Current Draw (Amps) Thermal Dissipation
Power
Draw
100-120 V 220-240 V btu/hr
(Watts)
3,534 42.6 19.4 3,187
2,845 34.3 15.6 2,606
2,156 26.0 11.8 2,026
1,467 17.7 8.0 1,445
779 9.4 4.3 864
kcal/hr
803
657
511
364
218
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