SSR 45-75 kW
Detail Specifications
INLET AIR FILTER:
Inlet air filtration for the SSR is accomplished by a large 99.9% efficient at 3 micron and above,
dry type air cleaner. This is more than suit-able for the vast majority of applications; however,
where high dust and dirt contamination is present, optional filtration systems are available.
COMPRESSION MODULE:
Since the airend is the fundamental component in any rotary screw compressor package,
reliability, performance and efficiency are deter-mined, for the most part, by the de-sign,
manufacturing tolerances and assembly of the airend itself. All other elements in the
compressor system are essentially support and monitoring devices, included to in-sure
dependable service and performance.
The rotors are manufactured from AISI-C-1141 forged steel. In larger size airends the
asymmetrical pro-file is developed through a unique two-step machining process. The first step
in the machining process develops the basic wrap angle pro-fileand is a rough cut. The second
and final step is a finish grinding process, which insures a hard true rotor surface. Rotor shafts
are precision ground to tolerances within 0.0005 of an inch. It is during the second step, that the
sealing strips are ground into the female rotor. The function of sealing strips as indicated by the
name, is to seal the compression chamber to minimize leakage and blow-by. Sealing strips are
of-ten likened to piston rings on a reciprocating compressor. After the ma-chining process has
been completed, each rotor is inspected on three axis for dimensional integrity. The rotors are
match-marked set prior to assembly in the rotor housing. The rotor housings are made of close
grain high quality cast iron. After machining, each housing is dimensionally checked to insure
accuracy.
Duplex Taper Roller Bearing Schematic
The bearing configuration used on all SSR models is the tapered roller bearing. The tapered
roller bearing essentially consists of constructing the roller elements, as well as the raceways,
so that lines drawn coincident with the working surfaces of the rollers and races will all meet at
a common point on the axis of the bearing. This allows the bearing to handle all loads, radial,
thrust or both. With this bearing configuration, the discharge end of the male and female rotors
are each equipped with a pair of tapered roller bearings offset at opposing axis for maximum
absorption of thrust and radial loads.
High quality cylindrical roller bearings are used to carry the radial loads on the inlet end of the
rotors. All bearings, whether thrust or radial, use premium cost vacuum degassed bearings,
which provide truer, harder running surfaces for both inner and outer bearing races. Coolant
dams are machined at the duplex taper roller bearing locations. The coolant dam provides an
area for coolant to collect or pond when the compressor is shut off. Upon startup the taper roller
bearing which is resting in coolant ponded by the coolant dam begins to rotate and is
immediately lubricated. Airends without coolant dams have bearing systems that operate dry
for approximately six seconds.
MAIN DRIVE MOTOR-GENERAL
The motor is exactly matched to the requirements of the SSR. Torque and load requirements of
the compressor were matched to specific design criteria that enabled the SSR motor to develop
peak efficiency and power factor at full load.
A. FRAME:
Motor frame and end brackets are of cast iron with integrally cast feet. This provides maximum
strength and rigidity for bearing support, uniform stator/rotor gap and flanged permanent
alignment of all mating parts.
B ELECTRICAL DESIGN:
Speed, torque and operating characteristics have been designed to match the load of the
compressor. Motor efficiency and power factor have been optimized to cover the entire capacity
range of the SSR.
C. BEARINGS:
Vacuum degassed ball bearings for the drive end and roller bearings for the discharge end
provide dependable and reliable ser-vice. These oversized bearings have an average applied
life of 135,000 hours, which is approximately eight times greater than NEMA standards. Both
bearings are grease lubricated with bearing housings having inlet and relief fit-tings to simplify
the lubrication procedures.
D. INSULATION:
The SSR high efficiency motor has class F insulation as standard. That means it is rated at
continuous duty for up to a 115°C temperature rise. However, no SSR motor is ever applied for
a temperature rise over 95°C, a difference of 20°C. Ordinary competitive motors, on the other
hand, use the lesser class B insulation, rated for a maximum of 90°C rise. Further, they are
routinely operated with a temperature rise of 82°C or more, a difference of only 8°C. That’s
really significant, since the motor life expectancy is doubled with every 10°C reduction in
temperature rise. The extra conservatism built into every SSR motor means more reliability,
increased life, and a much more forgiving motor under adverse conditions. And even with all
these unique features, the SSR motor still utilizes NEMA* and IEC** design standards.
E. WIRING:
All windings and leads are copper with triple coats of insulating varnish to add extra margins of
protection to the drive.
F. TESTING:
During manufacture and assembly, 40 different tests and quality control checks are made to
insure the SSR motors meet Ingersoll-Rand requirements.
INTEGRAL DRIVE ASSEMBLY:
In order to utilize the inherent efficiency advantage of the SSR motor and airend, it was
necessary to develop a means of efficiently transmitting power from the driver to the
compressor. The integral gear drive system was chosen because it is an efficient, reliable and
rugged design. Conservatively chosen speed optimizing gears are mounted on extended
shafts from the airend and motor. The flanged motor is doweled for permanent alignment to the
airend. The use of AGMA Class 11 gears allow the SSR airends to rotate at a specific speed,
which allows maximum airend efficiency. The gear housing is completely sealed against
atmospheric contaminants to insure lifetime trouble free power transmission. A self-centering
Teflon impregnated motor shaft seal provides a positive system against leak-age to the motor
winding. The entire assembly is vibration isolated from the package.
LUBRICATION SYSTEM
A. COOLANT FILTRATION:
The full capacity coolant filter is a 4 micron spin-on replaceable element with pressure bypass.
B. COOLANT/LUBRICANT HEAT EXHANGERS:
Integrally mounted aircooled heat exchangers are designed for ambient temperatures to
46°C/115°F. The core, fan and fan motor are all mounted and prewired in the compressor
package. Watercooled coolers are shell and tube type de-signed to use fresh cooling water at
inlet temperature up to 32°C/90°F.
C. COOLANT/LUBRICANT TEM-PERATURE CONTROL (AIR-COOLED
AND WATERCOOLED UNITS):
The thermostatic control valve with four ports, (1) coolant to the cooler, (2) for the coolant from
the cooler, (3) for the coolant from the pressurized receiver/separator, and (4) for the coolant to
the coolant injection orifices, is mounted in the piping system. The temperature sensitive
element controls the quantity of coolant from each source, cooled and uncooled, necessary to
pro-vide the proper injection temperature and assure fast warm-up.
D. COOLANT INJECTION:
On airends, the use of multiple ports is employed. Coolant is sprayed into the middle stages of
the compression cycle. To seal the inlet, there is limited injection at the female rotor. Full size
multiple ports give best flow cooling and sealing under a wide variety of operating conditions.
E. COOLANT/AIR SEPARATION:
After compression and discharge from the airend, the air heavily laden with coolant travels to
the receiver/separator. Entering through a radial inlet, the air coolant mixture is directed in a
circular motion around the inside of the tank. The vortex or circular motion separates a major
portion of the coolant from the air through centrifugal force. The air is then directed through the
conical baffle, which further reduces the coolant content. The vortex action and baffling results
in a pre-cleaning of the compressed air, prior to entering the separator element.
Separator element is a molded fiberglass two-stage reinforced separator. On all size SSR
compressors, the carry-over, after the separator element is 3-5 ppm. Compressed air then
enters the optional aircooled or watercooled aftercooler, where the carryover of 3-5 ppm will be
further reduced by the aftercooler and condensate separator to a final carryover figure of 2
ppm.
Hence, when calculating coolant makeup for SSR compressors, always use 3-5 ppm by weight.
Due to the conservative sizing of the separator element, there is a minimal 2 psig/13.8 kPa
pressure drop. This reduces the required HP to move the air through the compressor system.
CONTROL MODULE-GENERAL:
The SSR compressor includes a microprocessor based control module, which provides for
starting, capacity control, operating control, and safety control of the unit.
A. COMPRESSOR/CAPACITY CONTROLS:
As standard the SSR is provided with Intellisys Control on-line/off-line control. On-line/off-line
allows the compressor to operate at 2 points on the capacity curve. The first is 100% full-flow
and the second is 0 flow. The on-line/off-line control is a power savings mode of operation. The
unloaded operation pro-vides for immediate compressor system blowdown to minimize power
requirements. The compressor will automatically reload. to 100% capacity when the system
falls to a predetermined pres-sure.
Upper range modulation control combines the benefits of conventional modulation control with
the power savings advantages of on-line/off-line control. This mode of control is automatically
used when the demand for air is expected to be relatively high as compared to the compressor
capacity. As set at the factory, each SSR will modulate from 100% capacity to 60% capacity.
When the system calls for less than 60% of capacity from the compressor, the unit will
automatically unload and blow down to atmospheric pres-sure, again reloading if the system
pressure decays to a pre-determined setting.
INTELLISYS READOUTS
Display Standards
• Package discharge pressure
• Total hours/loaded hours
• Airend discharge temperature
• Sump pressure
• Separator element pressure drop
Adjustable Operating Parameters
• Off-line pressure
• On-line pressure
• Display time
• Mode of operation
• Delay load time
• Auto start and stop shutdown time
• Auto start and stop on/off
• Sequencer control on/off
• Remote start and stop on/off
• Lead/lag settings
Fault Warnings
• High airend discharge temperature
• Change separator element
Fault Shutdowns
• High airend discharge temperature
• Low unloaded sump pressure
• Calibration failure
• Emergency stop
• Starter failure
• Main/fan motor overload
• Reverse rotation
• Sensor failure
• Control power loss
• High air pressure
• Remote start failure
• Remote stop failure