Camco D-Power 7 - Manual (Page 20)

D - P O W E R
S E R I E S
USER MANUAL
D-POWER 7
P.19
4.3.5 DC Protection
Each output of the power amp is constantly monitored for persistent DC
voltage levels. If the 3 V threshold voltage is exceeded at any of the out-
puts, the main SMPS will shut down and the channel will be automatically
switched off. The microprocessor performs a sophisticated strategy to lo-
cate the cause of the malfunction. DC can be located in the output stage,
driver stage or at the input of the amplifier.
Output Stage
When a DC voltage is located at an output stage, the main SMPS remains
switched off. The On LEDs will show a flash sequence corresponding to
this malfunction (See 5 Troubleshooting).
Driver Stage
When a DC voltage is located at the driver stage only the defective chan-
nel’s output stage and the DCA are muted. The other channel continues to
work. The On LED of the defective channel will indicate the malfunction by
starting the relevant flash sequence (See 5 Troubleshooting).
Amplifier Input
When DC is located at the input stage only the DCA of the affected chan-
nel is muted. The other channel continues to operate normally. If the DC
signal at the input vanishes, the microprocessor will de-mute the affected
channel and the amplifier will work as usual again.
4.3.6 DC Servo
To prevent DC Offset at the speaker output the D-POWER 7 is fitted with two
DC Servos. (Hence there are no capacitors in the signal path)
4.3.7 Over Current Protection
The output stage is permanently monitored for possible current surges.
There are two limiting levels of over current depending on output voltage.
These limits will be set automatically. This improves reliability without de-
grading sound quality when driving complex loads.
4.3.8 Thermal Protection
The microprocessor uses several sensors in the amp in order to ascertain
tem perature data. If the microprocessor detects a temperature of more
than 85 °C at the heat sinks, the input signal on that channel is reduced. If
the temperature exceeds 100 °C, the main SMPS is switched off.
The On LED of the overheated channel will start a blinking-sequence (See
5 Troubleshooting).
4.4 Mains Protections
4.4.1 Inrush Current Limitation
Within 2 seconds of the D-POWER 7 being switched on, the inrush current
limiter will increase mains current from nearly zero to nominal value. This
value de pends on program material, output level and speaker loads.
4.4.2 Mains Over Voltage Detection
Mains Over Voltage Detection is always operative. When the mains voltage
exceeds approx. 267 V (230 V operation), 134 V (120 V operation) or 117
V (100 V operation), the amplifier will switch off. When the mains voltage
returns to nominal value, a soft start occurs.
4.4.3 Mains Failure Detection
Mains Failure Detection is always operative. When the mains supply is
interrupted for about 2 mains cycles, the amplifier will switch off. When the
mains voltage returns to a normal value, a soft start occurs.
4.4.4 Fuse Protection
The average mains current can peak temporarily, depending on the load
impedance and type of signal, at values several times higher than the
nominal value allowed by the fuse protection.
Continuous monitoring of the fuse protection status allows the conditions
that would trigger the fuse protection to be predicted. In order to avoid
shut-down of the amplifier due to current overload, the amplitude of the
input signals will be limited.
The limitation of the input signal allows a 6 kW D-POWER 7 power amplifier to
be operated reliably from a mains power supply of 230 V/16 A (120 V/30 A;
100 V/30 A).
4 OPERA
TION