Sullivan-Palatek 125UD, Operating And Parts Manual

Page: 10 / 64

SULLIVAN-PALATEK__________________________________
10
SECTION 3 DESCRIPTION
3.1 INTRODUCTION
SULLIVAN-PALATEK Plant Air Compressors are electric motor driven, single-stage rotary screw type,
continuous-duty compressor. They are designed and constructed to offer the greatest value and lowest
life cycle cost of operation. The compressor package includes: a direct-connected electric motor-driven
compressor, air intake/capacity control system, air-cooled cooling system (including a standard air-cooled
aftercooler), discharge system, instrument panel and electrical system. They are available base
mounted, with or without enclosures. These machines are intended for indoor installation, or protected
outdoor operation in moderate climates.
3.2 COMPRESSOR UNIT
All SULLIVAN-PALATEK compressors feature direct-connected, single-stage, positive displacement,
flood-lubricated rotary screw compressor units with heavy-duty long-life rolling element bearings. The
lubricoolant fluid is injected directly into the compressor unit and mixes with the air as the rotors compress
it. The lubricoolant lubricates the rotors, bearings and shaft seal, cools the compressor by absorbing
much of the heat of compression and acts to block slippage of compressed air through the compressor’s
internal clearances.
3.3 MOTOR
The electric motor used to power each SULLIVAN-PALATEK UD Series 125/250 horsepower compressor
is a NEMA special inverter duty 3 phase motor, fitted with a C-face register at the compressor drive end to
assure proper coupling alignment at all times. The main compressor motor is connectable for 460 volts.
All air cooled compressors utilize a separate TEFC fan motor. Contact the factory for any other
requirements, such as TEFC main drive motor.
3.4 INTAKE/CONTROL SYSTEM
The intake/control system consists of: an air filter, connecting rubber elbow, a combination compressor
inlet valve/reverse-flow check valve, blow-down valve, and control pressure transducer. (See Intake
Control Schematic.) The air filter is a multi-stage dry-type with a high efficiency cleanable/replaceable
cellulose element. The element should be cleaned periodically, depending upon the amount of particles
in the air, and replaced annually, of if a high delta-p fault is shown. If remote air intake is desired, consult
the factory for a special intake option.
The VFD controls the capacity or air delivery of the compressor in direct response to the plant air system
demand via a varying signal from the line pressure transducer, or an unload control signal. During
periods of very low or zero air usage the inlet valve is held shut by an air signal from the blow-down valve.
This air signal simultaneously reduces the pressure in the oil separation tank, allowing the compressor to
run unloaded with a minimum of power consumption. Upon shutdown the intake valve checks shut to
eliminate blowback.
CONTROL OPERATION - STARTING:
When the compressor start key is pressed, or starts automatically (signal from BLT or sequencer), it will
run for approximately 10 seconds unloaded. After this interval, the pressure will rise quickly to 60 PSIG
(415 KPA) which is the minimum pressure valve opening pressure. Until the controller pressure setting is
reached, the compressor inlet valve is wide open and the compressor will deliver its full rated capacity.
NORMAL FULL LOAD MODE:
From 60 psi to the control pressure setting the minimum pressure valve is open and the compressor
delivers its full rated capacity to the air receiver and/or the plant air piping system.