Description Of Components; Control System, Functional Description - Sullair LS-200 Operator's Manual And Parts List

10.1 DESCRIPTION OF COMPONENTS

Refer to Figures 2-1A
and assemblies of the air compressor are clearly
shown. The complete package includes compres-
sor, electric motor, variable speed drive,
Supervisor™ Controller, compressor inlet sys-
tem, compressor discharge system, compres-
sor lubrication and cooling system, capacity
control system, instrument panel, aftercooler,
and combination separator and trap, all mounted
on a heavy gauge steel frame.
On air-cooled models, a fan draws air over the
motor and forces it out through the combined after-
cooler and fluid cooler thereby removing the com-
pression heat from the compressed air and the
cooling fluid.
On water-cooled models, a shell and tube heat
exchanger is mounted on the compressor frame.
Fluid is piped into the heat exchanger where com-
pression heat is removed from the fluid. Another
similar heat exchanger cools the compressed air.
Both air-cooled and water-cooled versions have
easily accessible items such as the fluid filters and
control valves. The inlet air filter is also easily
accessible for servicing.
10.2 CONTROL SYSTEM, FUNCTIONAL DESCRIP-
TION
Refer to Figures 2-3A
The purpose of the compressor control system is to
regulate the amount of the air being compressed to
match the amount of compressed air being used.
The Capacity Control System consist of variable
speed drive, solenoid valve, regulating valve,
and the inlet valve. The functional description of
the control system is described below in six distinct
phases of operation. The following description text
applies to V-200 series variable speed drive com-
pressors with Supervisor Controller. Depending on
the model, the compressor can be operated at a
setpoint pressure from 60 to 175 psig (4.1 to
12.1 bar). Refer to the nameplate for operating
pressure range. The Supervisor Controller will
automatically set the frequency range based on
the selected pressure. For explanatory purposes,
this description will apply to a compressor with an
operating pressure of 100 psig (6.9 bar). A com-
pressor with any other pressure range would oper-
ate in the same manner except stated pressures.
START MODE- 0 – 50 PSIG (0 TO 3.5 BAR)
When the Supervisor Controller
is depressed, the VSD ramps the motor to full
and 2-1B. The components
or 2-3B (with spiral valve).
(START) button
VARIABLE SPEED DRIVE
speed and the sump pressure will quickly rise from
0 to 50 psig ( 0-3.4 bar). During this period, both the
regulator and solenoid valves are closed, the inlet
valve is fully open and the air-end delivers full
capacity to the sump tank. The rising compressor
air pressure is isolated from the service line in this
phase by the minimum pressure valve set at
approximately 50 psig (3.4 bar).
FULL LOAD MODE- 50 TO 100 PSIG (3.4 TO 6.9
BAR)
When the compressed air pressure rises over 50
psig (3.4 bar) the minimum pressure valve opens
allowing compressed air to flow into the service line.
From this point on the line pressure is continually
monitored by the Supervisor Controller, which con-
trols the variable speed drive. The pressure regula-
tor and solenoid valve remain closed with the inlet
valve fully open running at 100 psig (6.9 bar) or
below.
VARIABLE SPEED DRIVE PART LOAD CON-
TROL
If less than rated capacity of compressed air is
being used, the service line pressure will
above 100 psig (6.9 bar).
Variable Speed Drive will begin to decelerate the
motor, thereby reducing the output capacity to
match demand. The drive will continuously adjust
the motor speed (accelerate or decelerate) to main-
tain a line pressure of 100 psig (6.9 bar). In this
mode the VSD will operate within the appropriate
frequency range determined by the Supervisor
Controller.
MODULATING MODE- 100 (6.9 BAR) PSIG TO
106 PSIG (7.3 BAR)
During low demand periods and with the Variable
Speed Drive at minimum speed, the line pressure
can continue to rise. When the line pressure reach-
es 101-102 psig (approximately 7 bar), the regula-
tor valve gradually opens, directing air pressure to
the inlet control valve piston. This action causes the
inlet valve to partially close, thereby reducing the air
entering the compressor until it matches the
amount of air being used. The control system func-
tions continually in this manner between the limits
of > 101 psig (7.0 bar) to 106 psig (7.3 bar), in
response to varying flow demand.
The pressure regulator has an orifice which vents a
small amount of air to the atmosphere when the
pressure regulator controls the inlet valve. The ori-
fice also bleeds any accumulated moisture from the
control line. When the discharge pressure rises
above 106 psig (7.3 bar), or alternatively set unload
Section 10
rise
Consequently, the
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