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COMPONENT DESCRIPTION
3.1
AIR COMPRESSOR PACKAGE
The air compressor package consists of a rotary screw compressor unit, air-cooled lubrication and cooling
system, discharge system, intake and capacity control system and monitoring system.
This compressor package is part of the SP-series. The heart of the package is equipped with the new line
of SP compressor units which are robust in design for long life in numerous applications.
3.2
COMPRESSION CYCLE
During operation, two helically-grooved rotors mesh to compress air. Intake air is compressed as the male
lobes roll down the female grooves, pushing trapped air along, compressing it until a female groove uncov-
ers the discharge port in the end of the stator and delivers smooth-flowing, pulse-free air to the receiver.
Atmospheric air fills in behind the male lobe, preparing the female groove for another compression cycle as
rotation continues and the male lobe again meshes with the female groove.
FIGURE 3-1.
COMPRESSION CYCLE
3.2.1 COMPRESSOR UNIT
Within the compressor unit (also referred to as an airend) is where the compression cycle takes place. The
compressor unit is a lubricant-flooded, positive displacement, rotary screw type unit. It is a single-stage
design to achieve the desired operating pressure. The compressor unit’s main components include a stator
housing, discharge housing, male and female rotors, bearings and seals.
3.3
DRIVE SYSTEM
When the start button is pressed, the main motor starter contacts are pulled in and power is supplied to
the motor. Power is transferred directly from the motor to the compressor unit by the drive coupling to bring
the compressor unit up to operating speed. An adapter housing self-aligns the motor and compressor unit.
The power status and modes of operation are controlled through the starter assembly.
3.3.1 DRIVE MOTOR
The drive motor is the main electrical motor that powers the compressor unit. The electric motor is three-
phase induction type supplied with a C-flange that bolts directly to the motor/compressor adapter. Stan
-
dard motor configuration is an NEMA-rated ODP design. Optional motor configurations are available upon
request.
3.3.2 DRIVE COUPLING
The drive coupling transfers power from the drive motor to the compressor unit. The drive coupling consists
of two steel coupling halves (one for the motor shaft and one for the compressor unit shaft) and a replace-
able spider coupling element.
3.3.3 STARTER (ELECTRICAL CONTROL PANEL)
The starter (also referred to as the electrical control panel) is an amp-rated designed assembly. Types
of starter designs offered include Magnetic Full Voltage (MFV), Wye-Delta (YD) and Solid State Reduced
Voltage (SSRV). The selected physical starter contactors are designed to match motor ratings for the
supplied incoming power voltage. The standard starter enclosure is NEMA 12/4 for optimum protection of
the internal components. The control panel assembly houses the required electrical controls, main motor
contacts/overloads and fan starter contact/overload. The assembly is located at the left-side corner of the
package for easy access. If the main starter is SSRV in design, the enclosure is equipped with a cooling
system to help maintain the performance of the SSRV in elevated ambient conditions.
Summary of Contents for SP20
Page 12: ...4 Introduction ...
