Ashly PowerFlex 670 Manual de instruções - Página 10

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Operating Manual - Powerflex Multi-Channel 70V Power Amplifier

An AC power interruption will result in all chan-

nels entering protect mode simultaneously, just as if the

amplifier is being turned off.

In all cases, the amplifier will restart the signal

processing module after a short delay and will reconnect

the speakers after several seconds if no further fault con-

ditions exist. This allows the servo circuitry to bring any

residual DC offsets to zero before speakers are connected.

Specific conditions resulting in a fault are as follows:

8.1 Power supply undervoltage - Possible causes

would be total load on the outputs exceeding recommen-

dations (remove some speakers), low AC mains voltage

(reduce extension cord length or increase wire size, or

switch to an AC mains circuit more capable of supporting

the amplifier's power requirements), or improper AC inlet

mains voltage setting (make sure nominal AC mains volt-

age matches the number in the viewing window on the AC

inlet).

8.2 Power supply overvoltage - Possible causes

would be high AC mains voltage (change to an AC mains

circuit with voltage within the amplifier's stated require-

ments) or improper AC inlet mains voltage setting (make

sure nominal AC mains voltage matches the number in the

viewing window on the AC inlet).

8.3 Output overcurrent - more than 7 amperes

being drawn from any output. Possible causes would be

total load on the affected output exceeding recommenda-

tions (disconnect some speakers), or a short circuit on one

of the outputs driven by the affected module (inspect

speaker wiring for proper connection).

The above conditions are checked by the signal

processing module on a switching cycle by switching cycle

basis and are therefore monitored as often as a million or

more times a second, allowing protection well before de-

structive conditions have time to cause part failure.

8.4 Heat sink overtemperature - a measured heat

sink extrusion temperature of more than 85 to 90 degrees

C. The two-speed fan will switch to high speed at a tem-

perature of 70 to 75 degrees C. The overtemperature fault

will clear itself when the measured temperature is below

about 70 degrees C. The fan will operate at low speed

below about 50 degrees C.

8.5 Unacceptable DC or high frequency output

content - a DC offset in the output signal of more than a

few hundred millivolts indicates module failure, and will

trigger a DC protect fault. High frequency (above 20kHz)

in the output at high amplitudes can cause speaker dam-

age and will trigger a HF protect fault.

These two conditions (DC and HF) are tested by

the same circuit so the exact cause cannot be isolated. If

the fault condition persists after disconnecting all inputs

and outputs from the amplifier, there is probably a module

failure requiring service. Note: the self-testing circuit may

take as long as 30 seconds to recover from this fault, so be

sure to give the amplifier enough time to reset itself. If

after 30 seconds the module has recovered, begin plug-

ging in one input and output at a time in an effort to iso-

late a system high-frequency or oscillation problem.

8.6 AC power interruption - a dropout (or brown-

out of sufficient magnitude) of more than one half mains

line cycle and less than one whole cycle in duration.

TYPICAL APPLICATIONS

The Powerflex 670 is essentially three stereo am-

plifiers in one chassis, each with Independent, Parallel, and

Bridge mode, while the Powerflex 470 is two stereo am-

plifiers (four channels), but with more power per channel

than the 670. Note: The Powerflex 670 is used for the

following application details, but the 470 is used in a simi-

lar fashion, to a maximum of four channels.