3
Scroll Enclosure Air Compressors
20 Follow all directions for mainte-
nance. Check all safety devices
according to instructions.
21. Never attempt to lift or move the
compressor except when using the
proper lifting procedures.
22. Make sure all electrical components
follow the National Electric code
and all state and local codes when
installing the compressor.
23 Do not operate the compressor if
unusual noise or vibration occurs.
24. Keep all panels in place at all times.
25. Standard motors are not appropri-
ate for dirty, wet or explosive areas.
26. All service should be performed by
trained and qualified people only.
27. The Drive Belt tension should be
checked often during initial opera-
tion of the compressor.
28. Never substitute oil bath or oil wet-
ted filters for the inlet filters provid-
ed with the compressor.
COMPRESSION CYCLE
The Powerex Oilless Rotary Scroll Air
Compressor is based on the theory of
scroll compression. A scroll is a free
standing, intricate spiral bounded on
one side by a solid, flat plane or base. A
scroll set, the basic compression ele-
ment of a scroll compressor, is made up
of two identical spirals which form
right and left hand parts. One of these
scroll components is indexed or phased
180
o
with respect to the other so the
scrolls can mesh. Crescent-shaped gas
pockets are formed and bounded by
the spirals and the base plate of both
scrolls. As the moving scroll is orbited
around the fixed scroll, the pockets
formed by the meshed scrolls follow
the spiral toward the center and dimin-
ish in size. The moving scroll is prevent-
ed from rotating during this process so
the 180
o
phase relationship of the
scrolls is maintained. The compressor’s
inlet is at the outer boundary of the
scrolls. The entering gas is trapped in
two completely opposite gas pockets
and compressed as the pockets move
toward the center. The compressed gas
is discharged through the outlet at the
center of the fixed scroll so no valves
are needed.
MAGNETIC STARTER
The magnetic starter on model
SED1007 is located on the right hand
side of the cabinet. For models SET1507
and SEQ2007, the magnetic starter is
located inside the electrical box accessi-
ble from the front panel.
MOTOR OVERLOAD PROTECTION #
The motor overload protection on the
scroll compressor is controlled by an
overload relay which is located beneath
the magnetic starter. Please refer to the
electrical drawings for specifications.
CURRENT SENSOR *
Model SED1007 utilizes current sensors
to prevent motor overload. This device
is located next to the magnetic starter.
CONTROL TRANSFORMER
The control transformer on the scroll
compressor reduces line voltage to 200
volts for operation of the hourmeter,
ventilation fan, circuit board and pres-
sure sensor.
THREE PHASE MOTOR
Powerex three phase motors are TEFC,
NEMA frame motors suitable for 208V,
230V and 460V operation.
TIP SEAL
The tip seal on the scroll compressor is
self-lubricated and allows the unit to
operate efficiently without oil and
expensive filtration. The tip seal should
be replaced every 10,000 hours of oper-
ation.
BEARINGS
The bearings on the scroll compressor
are regreaseable to allow extended
compressor life. Service should be per-
formed every 10,000 hours of opera-
tion.
AIR COOLED AFTERCOOLER
The air cooled aftercooler on the scroll
compressor is a series of deep alloy
cooling fins and a high output cooling
fan. These cooling features allow the
scroll compressor to provide a maxi-
mum discharge air temperature of 60°F
above the ambient temperature.
DRY TYPE INLET FILTER
The inlet filter on the scroll compressor
assures 99% of particulate free air is
admitted to the unit. Change every
2,500 hours or more often in dirty loca-
tions. These filters can be accessed from
the front panel.
COOLING AIR CLEANABLE FILTER
SCREEN
The cooling air cleanable filter screen
on the scroll compressor is located on
the
right hand panel (*) or the rear (#)
of the unit and should be cleaned peri-
odically.
DIGITAL HOURMETER
The hourmeter on the scroll compressor
indicates the actual number of total
run hours of all air ends that have been
in operation. The hourmeter is also
used to determine maintenance and
service timing. The hourmeter is acti-
vated when one or more air ends is/are
running.
HIGH TEMPERATURE SHUTDOWN
SWITCH
The high temperature shutdown switch
on the scroll compressor protects the
unit when an unusually high tempera-
ture in the air end is detected. The com-
pressor will shutdown when this high
temperature is detected.
Component
Description
General Safety
Information (Cont)
* - Only available on 10 HP units (SED1007)
# - Only available on 15 & 20 HP units (SET1507, SEQ2007)
