Gardner Denver ELECTRA-SAVER EAYQ E, Руководство по эксплуатации и обслуживанию

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13–10–613 SP Page 18
SECTION 4
CONTROLS & INSTRUMENTATION
GENERAL DESCRIPTION – The Gardner Denver
rotary screw compressor is prewired with all controls,
motor, and starter for the voltage and horsepower at
the time of ordering. It is necessary only to connect the
compressor unit to the correct power supply and to the
shop air line (and to the appropriate water supply if wa-
ter cooled). A standard compressor unit consists of the
compressor, oil reservoir, oil cooling system and filter,
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 func-
tions under microprocessor control. Its functions in-
clude safety and shutdown, compressor regulation,
operator control, and advisory / maintenance indica-
tors. The keypad and display provide the operator with
a logical and easily operated control of the compressor
and indication 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). Compres-
sor operation may then be started by pressing an oper-
ating 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. Press the STOP/RESET key
at any time to stop the compressor under normal condi-
tions. If the compressor has been running, the reser-
voir will first be relieved of pressure before stopping the
motor. The display will count down to zero during the
normal 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.
If any alternate display is on, press the operating mode
key to return to the “normal” display. While operating
and running, the unit may be manually unloaded by
pressing and holding the operating mode key. This un-
loads a running compressor after several seconds, and
will prevent loading while the key is held down. When
the key is released, the control will resume its normal
operation as required.
An optional control may be wired into the “Auto Sentry
ES+ controller to interrupt and restart the unit based on
controls by others. When stopped by these controls,
the display indicates remote stop.
In any mode, the compressor will start only if reservoir
pressure is below 5 psig. The display will indicate 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 TVO (turn
valve open), TVC (turn valve close), IVO (inlet valve
open) and IVC (inlet valve close) to control the CFM of
the compressor to match the CFM demand of the air
system. As the demand changes, the controller will
continue adjustment for the best compressor opera-
tion. At moderate to heavy demand, the inlet will be
held open, and the turn valve will control delivery. At
lighter demands, the turn valve will be fully open, and
the inlet valve will control capacity. At very light de-
mand, the compressor will unload, but will not blow
down the reservoir. It will reload just below the set pres-
sure. The controller will thus maintain the pressure
within a few psi of the set pressure.
If the controller is programmed for “load–unload” op-
eration, the controller will deliver full capacity until the
system pressure reaches the set pressure. It will then
unload (but not blow down) and will not deliver any air
to the system. When the system pressure falls to half-
way between the set and reset pressure, the ES+ con-
troller again fully loads the compressor.
When first starting, the controller will keep the com-
pressor fully unloaded and blown down until the system
pressure drops below the reset pressure. Once
loaded, the reservoir will remain fully charged, regard-
less of demand. Responses to demand are thus im-
mediate, as soon as system pressure drops below the
setpoint.