Temperature Protection; Power Average Limiter (Pal); Soft Start - Lab.gruppen C 68:4 Operation Manual

7 OPERATION AND PERFORMANCE

7.5.7 Temperature protection

Thermal measurement points are provided on each
output channel as well as on the power supply. These
indicators will, if the pre-specified temperature level
is exceeded, give a high temperature warning. This
warning condition is indicated by a flashing Temp LED
on the front panel, and it is reported on the Device
Control GUI via the NomadLink network.
As the amplifier approaches a thermal protection
threshold, the warning LED sequence will start with
short "on-time" bursts. If the amplifier continues
to overheat and approaches the temperature limit,
the flashing sequence will be defined by longer and
longer on-time bursts until the protection mode is
activated.
If the temperature becomes too high to continue
safe operation, the overheated output channel(s)
will be muted until the temperature returns to an
acceptable level.
Fully active temperature protection (with muting) is
indicated by a constantly illuminated Temp LED. It
will also be indicated as a fault via the NomadLink
network on the DeviceControl GUI.
Temperature measurements will continue at 6
second intervals. The output will un-mute when the
channel or power supply returns to a safe operating
temperature.

7.5.8 Power Average Limiter (PAL)

The Power Average Limiter (PAL) controls the
current-drawing relationship between the power
supply and the mains inlet. PAL limits the maximum
average power consumption according to the power
supply capabilities, ensuring that the PSU will not
overload. In addition, in the larger models that
potentially could pull more current from the mains
than the mains-fuses are specified to handle (more
than 16 A), PAL limits the amplifier's maximum
current draw to prevent blowing the mains fuse.

7.5.9 Soft Start

High powered amplifiers with inadequate inrush
limiting can pull considerable current from the
mains at turn-on. This can result in fast acting mains
breakers tripping. Such is not the case with C Series
amplifiers. The C Series amplifiers have very low
inrush power as the capacitors are charged slowly
0 C Series Operation Manual
and in a controlled manner ensuring that breakers
will not trip.
Several amplifiers will, under normal conditions, be
able to be powered up simultaneously. If you do
experience problems powering up multiple amplifiers
simultaneously, use the NomadLink network and the
NLB60E to establish a power sequence with a pre
set delay between each amplifier start-up.