13–11–602 Page 21
SECTION 4
CONTROLS & INSTRUMENTATION
GENERAL DESCRIPTION – The Gardner Denver
TWISTAIR
waterflooded rotary screw compressor is
prewired with all controls, motor, and starter for the volt-
age and horsepower at the time of ordering. It is neces-
sary only to connect the compressor unit to the correct
power supply, to the shop air line, and to the appropri-
ate water supply. A standard compressor unit consists
of the compressor, water reservoir, water cooling sys-
tem and filters, lubrication reservoir and pump, motor
type as specified, NEMA 12 starter/control box, and
control components as described below.
This compressor unit features the “AUTO SENTRY–
ES” controller, which integrates all the control functions
under microprocessor control. Its functions include
safety and shutdown, compressor regulation, operator
control, and advisory/maintenance indicators. The
keypad and display provide the operator with a logical
and easily operated control of the compressor and in-
dication of its condition.
AUTO SENTRY
–ES OPERATION
Operation of the “Auto Sentry–ES” is dependent on
selection of an operating mode (described below) from
the controller keypad. Prior to starting, the “STOP/RE-
SET” key must be pressed to place the controller into
its READY state (as indicated on the display). Com-
pressor operation may then be started by pressing an
operating mode key. Once operating, the mode may be
changed at any time by pressing a key, and the se-
lected mode will be displayed in the lower right corner
of the message window. The STOP/RESET key may
be pressed at any time to stop the compressor under
normal conditions. If the compressor has been run-
ning, the reservoir will first be relieved of pressure be-
fore stopping the motor.
An optional control may be wired into the “Auto Sentry”
controller to interrupt and restart the unit based on con-
trols by others. When stopped by these controls, the
display indicates remote stop.
Automatic restarting or electrical
shock can cause injury or death.
Open, tag and lockout main discon-
nect and any other circuits before
servicing the unit.
In any mode, the compressor will start only if reservoir
pressure is below 5 psig (.3 bars). The display will indi-
cate if the control is waiting for a reservoir blowdown,
along with the remaining pressure. The controls also
delay initial loading of the compressor until a startup
delay has been completed.
Constant Run Mode Operation – This mode is best
used in applications where there are no long periods of
unloaded operation, or for minimum response time to
sudden demands. The compressor unit will start and
run continuously, using its modulation controls to
match delivery to demand.
As demand falls below the compressor capacity, the
pressure will rise to the setpoint of the control. When
the pressure reaches the setpoint, the “Auto Sentry–
ES controller operates the solenoid valves IVO and IVC
to pass pressure to the inlet valve piston, and the inlet
valve will close enough to match it to the air system de-
mand.
As demand increases, the controller will modulate the
inlet valve by passing pressure with the solenoid valves
as required to provide the most economical means of
matching delivery to demand. Once the compressor
has been first loaded, it will maintain pressure within a
few psi of the setpoint pressure for any demand within
its rated capacity.
Low Demand Mode Operation – The low demand
mode reduces power consumption by relieving pres-
sure in the reservoir during unloaded operation. This
mode is best used where there is moderate air storage
and there are unloaded periods during the day, but fre-
quent motor starting and stopping is undesirable. Dur-
ing periods of moderate to high demands, this mode is
identical to the constant–run mode described above.
During low demand periods, the controller will open the
blowdown valve and fully close the inlet valve to mini-
mize the motor load. A timer is reset when this occurs.
While in this state, control air pressure is supplied from
the plant air system (as are any plant loads). When the
system air pressure drops to the reset pressure due to
increased demand, the blowdown valve recloses and
the controls resume their normal modulation se-
quence.
Subsequent blowdown periods are not allowed until the
timer has completed its cycle. This cycle eliminates
frequent blowdowns during moderate loads, and the
energy required to repressurize the reservoir. The tim-
er is adjustable from 5 to 20 minutes.
Automatic Mode Operation – This mode provides
automatic start and timed stop, and is best used in ap-
Summary of Contents for TWISTAIR EWDQ D
Page 14: ...13 11 602 Page 4 FIGURE 1 6 AIR WATER SCHEMATIC FIGURE 1 7 OIL SCHEMATIC...
Page 17: ...13 11 602 Page 7 DECALS 206EAQ077 212EAQ077 218EAQ077 211EAQ077 207EAQ077...
Page 18: ...13 11 602 Page 8 DECALS 216EAQ077 206EWD077 222EAQ077 221EAQ077 208EAQ077...
Page 35: ...13 11 602 Page 25 FIGURE 4 2 FLOW CHART FOR SET UP PROGRAMMING...
Page 44: ...13 11 602 Page 34 FIGURE 4 6 CONTROL TUBING SCHEMATIC 206EWD797 A Ref Drawing...
Page 48: ...13 11 602 Page 38 FIGURE 4 10 WIRING DIAGRAM FULL VOLTAGE 202EWD546 REF DRAWING...
Page 49: ...13 11 602 Page 39 FIGURE 4 11 WIRING DIAGRAM WYE DELTA 203EWD546 REF DRAWING...
Page 50: ...13 11 602 Page 40 FIGURE 4 12 AUTO SENTRY ES CONTROLLER DISPLAY...
Page 53: ...13 11 602 Page 43 FIGURE 5 2 FLOW DIAGRAM AIR COOLED 202EWD797 B Ref Drawing...
Page 54: ...13 11 602 Page 44 FIGURE 5 3 FLOW DIAGRAM WATER COOLED 203EWD797 A Ref Drawing...
Page 68: ......
