Sullair TSR20, User Manual

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TSR32 USER MANUAL R00 SECTION 2
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System consist of variable speed drive and spiral
valve . The functional description of the control
system is described below in five distinct phases of
operation. The following description text applies to
TSR-20 variable speed drive compressors with
The compressor can be
operated at a setpoint pressure from 100 to 175
psig (4.1 to 12.1 bar) along with a horsepower
range from 200 to 300 HP. The Supervisor
range based on the selected pressure and
horsepower. For explanatory purposes, this
description will apply to a compressor with an
operating pressure of 100 psig (6.9 bar). A
compressor with any other pressure range would
operate in the same manner except stated
pressures.
PSIG (0 TO 3.4 BAR)
START )
button is depressed, the VSD ramps the motor to full
speed and the sump pressure will quickly rise from 0
to 50 psig (0-3.4 bar). During this period, the solenoid
valve is 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 is
opened allowing compressed air to flow into the
service line. From this point on the line pressure is
which controls the variable speed drive. The solenoid
valve remains closed with the inlet valve fully open
running at 100 psig (6.9 bar) or below.
VARIABLE SPEED DRIVE PART LOAD CONTROL
If less than rated capacity of compressed air is being
used, the service line pressure will rise above 100
psig (6.9 bar). Consequently, the 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 maintain a line pressure
of 100 psig (6.9 bar). In this mode the VSD will
operate within the appropriate frequency range
determined by the Su
MODULATING MODE WITH SPIRAL VALVE:
As demand decreases, the variable speed drive
reduces motor speed to maintain the set point pres-
sure. When the speed approaches the minimum
setting, a solenoid valve opens feeding air pressure
to the spiral valve actuator. This in turn expands the
diaphragm and engages the pinion mounted on the
spiral valve shaft assembly, resulting in a rotary
motion and full opening of the spiral valve, effec-
tively reducing the rotor length by 50%. Excess air
will be returned back internally to the suction side of
the compressor unit. In this mode, the VSD will
modulate the motor speed within a specified range to
maintain the set point pressure as follows:
Increasing demand condition:
If demand increases, the VSD increases the motor
speed until the set point pressure is achieved. If set
point pressure is not achieved while at maximum
speed, the controller will close the spiral valve,
thereby eliminating internal air bypass.
Consequently, the VSD will regulate the motor speed
to achieve the set point pressure.
Decreasing demand condition:
While the spiral valve is open, if demand continues to
decrease the VSD will reduce the motor speed until
the set point pressure is achieved. This action will
continue until the minimum speed is reached. When
the system pressure reaches 106 psig (7.3 bar), or
alternatively set unload pressure, the compressor
unloads, or turns off.
UNLOAD MODE- IN EXCESS OF 106 PSIG (7.3 BAR)
When a relatively small amount or no air is being
used, the service line pressure continues to rise.
When it exceeds 106 psig (7.3 bar), or alternatively
control system de-energizes the solenoid valve
allowing sump air pressure to be supplied directly to
close the inlet valve. Simultaneously, the solenoid
valve sends a pneumatic signal to the blow down
valve. The blow- down valve opens to the
atmosphere, reducing sump pressure. The check
valve in the air service line prevents line pressure
from returning to the sump. The compressor will shut
down after the unload time setting expires if
programmed (the default setting is zero [0] seconds
for an immediate shutdown upon unload).
When the line pressure drops to the low setting
pressure of 100 psig (6.9 bar) The Supervisor
noid valve which closes the blow down valve. The
re-energized solenoid valve prevents line pressure
from reaching the inlet control valve, thereby allow-
ing it to fully open.
AUTOMATIC OPERATION
For VSD applications, th
allows the compressor to shutdown when no com-
pressed air requirement is present and restarts when
compressed air is needed. Restart will only take
place when sump pressure is below 5 psig.