Quinny QSD 65040-AB User Manual

33

While running in Back-up Mode, there is no power going
to the electronic control. The displays on the electronic
control will be dark and the keypad will be inactive.
Pressures and temperatures may be read on the gauges
located at the package discharge connection.

There are two modes of operation that can be used for
single machine installations, Continuous Run and Auto
Dual.

In Continuous Run Mode, the compressor uses an
adjustable  pressure deadband to match compressor
output to system demand.  As the pressure rises above the
full-load pressure setting, a signal is sent to unload the
airend, reducing the air delivery. Should the pressure rise
to a point indicating there is no system demand, the
control will unload the compressor and blow the piping
down to atmospheric pressure.  It will continue to run in
this unloaded state until system pressure drop indicates
additional air demand.

This control mode is best used for systems that have only
brief periods of time with no system demand.  Systems
with little compressed air storage capacity will also run
better with a control scheme using a pressure deadband to
moderate changes in loading levels.

This method of control operates identically to the
Continuous Run Mode when responding to a system
demand.  If there is no system demand, Auto Dual
control goes a step beyond Continuous Run to provide
additional power savings.  In the Auto Dual Mode, the
control will start a shutdown timer when the compressor
unloads.  The timer will count down a preset waiting
period.  If there has been no drop in system pressure
during this waiting period, the control will turn the
compressor motor(s) off and will stand by, continuing to
monitor system pressure.  When a demand returns to the
system, the controller will restart the compressor to
satisfy the air requirements.

Auto Dual Mode is best used for systems that have
extended periods (usually half an hour or more) during
which there is no system demand.  A very small
continuous system demand can be handled with adequate
compressed air storage capacity and a reasonable
pressure deadband, allowing the power savings
associated with having the compressor turned off.

The factory setting for this delay is ten (10) minutes.  The
purpose of the delay is to prevent the motor from starting
too many times within a given period.  To maximize the
energy savings benefit of having the machine off instead
of just unloaded, this timer should be set low enough to
allow the machine to turn itself off during periods of no
demand.

If the compressor attempts to start too many times, a
safety timer will be activated which forces a 25-minute
cool-down period.  The control will then reset and allow
the machine to shut down based on the adjustable timer
setting.

The control method used for multiple Power$ync II

™

compressor installations is the Network Mode.
Connecting multiple machines to form a network,
scheduling machines and sequencing machines are
thoroughly covered in this section.  In Network Mode, all
compressors share information about their capacity,
configuration and load setting.

Network Mode uses an adjustable pressure band for
controlling the compressor response to changes in system
demand.  With the system at full load (all compressors
operating at their maximum output) an increase in system
pressure above the set pressure indicates a drop in
demand.  The control will respond by unloading the trim
machine in the sequence.