Danfoss RDM Service guide
Service Manual
Cartridge Mount
Reverse Displacement Motors (RDM)
powersolutions.danfoss.com
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
Revision history |
Table of revisions |
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May 2016 |
new housing |
0104 |
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February 2015 |
update Port locations and gauge installation |
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November 2014 |
add K Frame |
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May 2014 |
First edition - Danfoss layout |
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2 | © Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 |
Service Manual |
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Reverse Displacement Motors (RDM), Cartridge Mount |
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Contents |
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General Information |
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Overview.............................................................................................................................................................................................. |
4 |
Safety precautions............................................................................................................................................................................ |
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Symbols used in Danfoss literature............................................................................................................................................ |
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Basic Design........................................................................................................................................................................................ |
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Key Features....................................................................................................................................................................................... |
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Schematic Diagrams........................................................................................................................................................................ |
7 |
Technical Specifications |
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Overview.............................................................................................................................................................................................. |
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Features and Options...................................................................................................................................................................... |
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Specifications..................................................................................................................................................................................... |
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Operating Parameters..................................................................................................................................................................... |
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Electrical Parameters....................................................................................................................................................................... |
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Fluid Specifications.......................................................................................................................................................................... |
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Features |
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Output shafts................................................................................................................................................................................... |
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Controls............................................................................................................................................................................................. |
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Pressure measurements |
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Required tools................................................................................................................................................................................. |
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Port locations and gauge installation..................................................................................................................................... |
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Initial start-up procedures |
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General .............................................................................................................................................................................................. |
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Startup-procedure......................................................................................................................................................................... |
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Fluid and filter maintenance |
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Recommendations........................................................................................................................................................................ |
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Troubleshooting |
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Excessive noise and/or vibration.............................................................................................................................................. |
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System operating hot................................................................................................................................................................... |
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Motor shifting irregularities....................................................................................................................................................... |
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Minor repair |
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Shaft seal replacement................................................................................................................................................................. |
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Remove the shaft seal............................................................................................................................................................. |
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Inspect the components........................................................................................................................................................ |
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Install the new shaft seal........................................................................................................................................................ |
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Shifting Valve................................................................................................................................................................................... |
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Remove shifting valve............................................................................................................................................................. |
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Inspect the components........................................................................................................................................................ |
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Install shifting valve................................................................................................................................................................. |
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Anti-Cavitation Valve.................................................................................................................................................................... |
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Remove the anti-cavitation valve....................................................................................................................................... |
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Inspect the components........................................................................................................................................................ |
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Install the anti-cavitation valve............................................................................................................................................ |
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Speed Sensor installation and adjustment........................................................................................................................... |
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© Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 | 3 |
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
General Information
Overview
This manual includes information for the installation, maintenance, and minor repair of the Reverse Displacement Motors (RDM). The manual includes a description of the units and their individual components, troubleshooting information, and minor repair procedures. Performing installation, maintenance, and minor repair of RDM Motors according to the procedures in this manual will not affect your warranty.
Performing minor repairs requires the unit to be removed from the vehicle/machine. Thoroughly clean the unit before beginning maintenance, or repair activities. Since dirt and contamination are the greatest enemies of any type of hydraulic equipment, follow cleanliness requirements strictly. This is especially important when changing the system filter and when removing hoses or plumbing.
A worldwide network of Danfoss Authorized Service Centers (ASCs) is available for major repairs. Major repairs require the removal of the unit's endcap, which voids the warranty unless done by an ASC. Danfoss ASCs are trained by the factory and certified on a regular basis. You can locate your nearest ASC using the distributor locator at www.powersolutions.danfoss.com.
Safety precautions
Always consider safety precautions before beginning a service procedure. Protect yourself and others from injury. Take the following general precautions whenever servicing a hydraulic system.
W Warning
Unintended vehicle or machine movement hazard
When using the RDM in combination with S45 open circuit pumps with LS or EPC be aware that there will likely be motor movement as long as the engine is turning. Due to the LS-setting of the pump, a standby pressure will remain in the system even if the normally closed control is fully energized. Lowest standby pressures to the motor, 15-18bar or above, may be enough to turn the RDM and has the potential to cause injury or damage.
W Warning
Flammable cleaning solvents
Some cleaning solvents are flammable. To eliminate the risk of fire, do not use cleaning solvents in an area where a source of ignition may be present.
W Warning
Fluid under pressure
Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious injury and/or infection. This fluid may also be hot enough to cause burns. Use caution when dealing with hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, gauges, or components. Never use your hand or any other body part to check for leaks in a pressurized line. Seek medical attention immediately if you are cut by hydraulic fluid.
W Warning
Personal safety
Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.
4 | © Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 |
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
General Information
Symbols used in Danfoss literature
WARNING may result in injury
CAUTION may result in damage to product or property
Reusable part
Non-reusable part, use a new part
Non-removable item
Option - either part may exist
Superseded - parts are not interchangeable Measurement required
Flatness specification
Parallelism specification
External hex head
Internal hex head
Torx head
O-ring boss port
Tip, helpful suggestion
Lubricate with hydraulic fluid
Apply grease / petroleum jelly
Apply locking compound
Inspect for wear or damage
Clean area or part
Be careful not to scratch or damage Note correct orientation
Mark orientation for reinstallation Torque specification
Press in - press fit
Pull out with tool – press fit
Cover splines with installation sleeve
Pressure measurement/gauge location or specification
The symbols above appear in the illustrations and text of this manual. They are intended to communicate helpful information at the point where it is most useful to the reader. In most instances, the appearance of the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.
Basic Design
The Reverse Displacement Motors (RDM) are medium power two-position axial piston motors incorporating an integral servo piston. They are especially designed for operation in open circuit, non propel applications. With the ability to shift over center, this motor combines reversing functionality and the simplicity of open circuit design without the need for additional, external valves (HIC’s). For fan drive system design guidelines refer to Danfoss publication: Hydraulic Fan Drive Systems - Design Guidelines,
520L0926
The RDM uses the existing and proven technology of the Danfoss L/K motor. These motors have been optimized with regard to options, life, package size and installed cost. The RDM consists of five unique rotating groups (displacements) in two housings with cartridge mounting flanges. Maximum speeds and maximum applied pressures for each displacement vary. The standard control is an integrated shift valve that uses system pressure. The integral servo piston controls motor displacement. The motor is spring biased to forward displacement and hydraulically shifted to reverse displacement.
Displacement for both directions is set with fixed internal stops. The integrated shifting valve in combination with large diameter servo piston allows smooth shifting between forward and reverse rotation. For system protection the motors are equipped with an integrated anti-cavitation and shock valve. The motor is ideally configured for installations requiring compact packaging and optimized plumbing with one face of the motor containing all hydraulic porting.
© Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 | 5 |
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
General Information
K Frame Cross Section
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Servo piston |
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Slipper |
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Bias springs |
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Piston |
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Swashplate |
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Valve plate |
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Output shaft |
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Endcap |
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Shaft seal |
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Cylinder block |
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Bearing |
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Key Features
Designed For Durability and Flexibility
•Designed for open circuit applications
•Five displacements allow the optimum selection of a hydraulic motor to fit your application
•Uses the existing and proven technology of Danfoss L/K motors, for maximum reliability
Installation and Packaging Benefits
•Short and compact total installed package
•High Efficiency - nine piston rotating groups with a positive and negative 18 degree maximum angle
•Uses system pressure for shifting - no external pressure supply needed
•Integrated shifting valve enables reversing - no external valves needed, which means less hoses, less losses providing a simple and clean installation
•12Vdc and 24 Vdc shifting valves
Wide Range of Options
•Fail Safe: Without control signal, the motor is biased to maximum forward speed
•Damped shifting
•Shaft options with dust seal protector
•Integrated system protection - anti-cavitation and shock valve
•High capacity bearings to withstand axial fan forces
•Complimentary to Danfoss Series 45 open circuit pumps with electronic proportional control
•PLUS+1 micro controller with fan drive software available
•Variety of porting options allow for easier system configurations
6 | © Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 |
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
General Information
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‒Metric O-Ring boss
‒SAE O-Ring boss
‒Split flange
A speed sensor is available
Schematic Diagrams
Pressure port A (CW rotation) |
Pressure port B (CCW rotation) |
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A |
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reverse |
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reverse |
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RDM |
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RDM |
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Cartridge |
B |
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Cartridge |
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L1 |
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L1 |
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P108731 |
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© Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 | 7 |
Service Manual
Reverse Displacement Motors (RDM), Cartridge Mount
Technical Specifications
Overview
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Specifications and operating parameters for RDM motors are given here for quick reference. For |
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additional information, see Operating Parameters, Features and Options, and Product Coding. |
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Features and Options |
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Cartridge |
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Motor type |
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Inline, axial piston, open circuit, reverse displacement motors |
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Displacement |
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L: 25, 30, or 35 cm3 [1.50, 1.83, or 2.14 in3]K: 38 or 45 cm3 [2.32, or 2.75 in3] |
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Rotation |
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Bidirectional |
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Installation position |
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Discretionary: Housing must always be filled with hydraulic fluid |
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Porting |
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Split flange - SAE O-ring boss, Metric O-ring boss |
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Output shafts |
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Tapered, 0.875 in Dia, 1.5 in/ft taper; Straight key, 0.875 in Dia, with dust seal |
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Control options |
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Integrated shift valve, 12Vdc/24Vdc |
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Displacement limiter |
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Fixed maximum and minimum displacement limiters available |
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Dust seal |
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Standard - refer to Features and Options in the RDM Technical Information manual. |
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High capacity bearing |
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Standard - more options available |
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Speed sensor |
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Available - refer to Features and Options in the RDM Technical Information manual. |
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Anti-Cavitation-Valve |
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Standard - refer to Features and Options in the RDM Technical Information manual. |
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Specifications |
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Parameter |
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Unit |
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LM25 |
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LM30 |
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LM35 |
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KM38 |
KM45 |
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Displacement (maximum) |
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cm3 [in3] |
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25 [1.50] |
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30 [1.83] |
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35 [2.14] |
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38 [2.32] |
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45 [2.75] |
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Weight (cartridge and SAE-B) |
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kg [lb] |
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17.5 [38.6] |
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Mass moment of inertia of rotating components |
kg•m2 |
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0.0017 |
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0.0016 |
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0.0015 |
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0.0023 |
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0.0023 |
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[slug•ft2] |
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[0.0012] |
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[0.0012] |
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[0.0011] |
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[0.0017] |
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[0.0017] |
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Theoretical torque |
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N•m/bar |
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0.40 |
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0.48 |
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0.56 |
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0.60 |
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0.72 |
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[lbf•in/1000psi] |
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[244] |
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[293] |
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[347] |
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[366] |
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[439] |
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Operating Parameters |
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Parameter |
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Unit |
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LM25 |
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LM30 |
LM35 |
KM38 |
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KM45 |
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System pressure |
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rated/continuous |
bar [psi] |
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260 [3770] |
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260 [3770] |
260 [3770] |
260 [3770] |
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260 [3770] |
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maximum |
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350 [5075] |
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350 [5075] |
325 [4715] |
350 [5075] |
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325 [4715] |
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Output speed |
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rated |
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min-1 (rpm) |
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3400 |
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3500 |
3600 |
3600 |
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3500 |
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(at max. disp.) |
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maximum |
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3950 |
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4150 |
4300 |
4000 |
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3900 |
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Case pressure limits |
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Rated |
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bar [psi] |
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0.5 [7] above outlet pressure, 2 [29] maximum pressure |
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Maximum |
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2 [29] above outlet pressure, 6 [87] maximum pressure |
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8 | © Danfoss | May 2016 |
L1427366 | AX00000144en-US0104 |
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