Danfoss Series 51 and 51-1 Bent Axis Variable Displ. Motors User guide

Technical Information
Bent Axis Variable Displ. Motors
Series 51 and 51-1
powersolutions.danfoss.com
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Revision history Table of revisions
Date Changed Rev
October 2017 Modified theor. corner power ratings and updated to Engineering Tomorrow 0401
March 2015 Major update. Corrected DITA CMS structure, layout, colors and all tables. CA
Jun 2005 First version AA
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Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors

Contents

Series 51 general information
Sectional view of Series 51, proportional control.................................................................................................................7
Sectional view of Series 51-1, two-position control.............................................................................................................8
Pictorial diagram...............................................................................................................................................................................9
System circuit diagram...................................................................................................................................................................9
Series 51/51-1 name plates........................................................................................................................................................ 10
Technical specifications
General specifications.................................................................................................................................................................. 11
Specific data.....................................................................................................................................................................................11
Fluid specifications........................................................................................................................................................................12
Determination of nominal motor size....................................................................................................................................13
General technical specifications
Case pressure...................................................................................................................................................................................14
Speed range.....................................................................................................................................................................................14
Pressure limits................................................................................................................................................................................. 15
Loop flushing...................................................................................................................................................................................16
Minimum displacement limiter................................................................................................................................................ 17
Hydraulic fluids............................................................................................................................................................................... 17
Temperature and viscosity......................................................................................................................................................... 18
Filtration system ............................................................................................................................................................................18
Fluid selection................................................................................................................................................................................. 19
Reservoir............................................................................................................................................................................................19
Independent braking system.................................................................................................................................................... 19
Motor bearing life.......................................................................................................................................................................... 20
External shaft loads....................................................................................................................................................................... 21
External shaft load orientation..................................................................................................................................................21
Radial and thrust loads to the output shaft.................................................................................................................... 22
Allowable external shaft load, when shaft load distance is different from standard.................................22
Efficiency graphs and maps....................................................................................................................................................... 23
Speed sensor................................................................................................................................................................................... 25
Typical control and regulator applications...........................................................................................................................26
Controls circuit diagram – nomenclature – description
Option N1NN – hydraulic two-position control for 51-1 (frame size: 060, 080, 110).............................................27
Option HZB1 – hydraulic two-position control for 51 (frame size: 160, 250)........................................................... 28
Options TA** – pressure compensator control for 51-1 (frame size: 060, 080, 110)..............................................30
Option TACA: pressure compensator configuration with hydraulic Brake Pressure Defeat.........................31
Options TAD1, TAD2, TAD7: pressure compensator configuration with electric BPD.................................... 31
TAD* solenoid connectors............................................................................................................................................... 31
Option TAC2: pressure compensator configuration without Brake Pressure Defeat......................................31
Options TA** – pressure compensator controls for 51 (frame size 160, 250).......................................................... 33
Option TAC0: pressure compensator configuration with hydraulic Brake Pressure Defeat......................... 34
Option TAC2: pressure compensator configuration without Brake Pressure Defeat......................................34
Options TH** – hydraulic two-position control for 51-1 (frame size: 060, 080, 110)............................................. 35
Pressure Compensator OverRide (PCOR).........................................................................................................................35
Option THCA: pressure compensator configuration with hydraulic Brake Pressure Defeat.........................36
Options THD1, THD2, THD7: pressure compensator configuration with electric BPD....................................36
THD* solenoid connectors...............................................................................................................................................37
Option THC2: pressure compensator configuration without Brake Pressure Defeat......................................37
Options TH** – hydraulic two-position control for 51 (frame size 160, 250)............................................................38
Pressure Compensator OverRide (PCOR).........................................................................................................................38
Option THC0: pressure compensator configuration with hydraulic BPD............................................................ 39
Option THC2: pressure compensator configuration without Brake Pressure Defeat......................................39
Options E1B1, E2B1, E7B1 – electrohydraulic two-position control for 51-1 (frame size 060, 080, 110)........40
E1B1, E2B1, E7B1 solenoid connectors............................................................................................................................. 41
Options E1A5, E2A5 – electrohydraulic two-position control for 51 (frame size 160, 250).................................42
E1A5, E2A5 solenoid connectors.........................................................................................................................................43
Options F1B1, F2B1 – electrohydraulic two-position control for 51-1 (frame size 060, 080, 110)....................44
F1B1, F2B1 solenoid connectors......................................................................................................................................... 45
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Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Contents
Options F1A5, F2A5 – electrohydraulic two-position control for 51 (frame size 160, 250).................................46
F1A5, F2A5 solenoid connectors.........................................................................................................................................47
Options T1**, T2**, T7** – electrohydraulic two-position control for 51-1 (frame size 060, 080, 110)...........48
Option T*CA: pressure compensator configuration with hydraulic Brake Pressure Defeat..........................49
Options T*D1, T*D2, T* D7: pressure compensator configuration with electric BPD......................................49
T1D1, T2D2, T7D7 solenoid connectors......................................................................................................................50
Option T*C2: pressure compensator configuration without Brake Pressure Defeat.......................................50
Options T1**, T2** – electrohydraulic two-position control for 51 (frame size 160, 250)................................... 51
Option T*C0: pressure compensator configuration with hydraulic Brake Pressure Defeat.......................... 52
Option T*C2: pressure compensator configuration without Brake Pressure Defeat.......................................52
T1C2, T2C2 solenoid connectors................................................................................................................................... 52
Options EP**, EQ** – electrohydraulic proportional control for 51 (all frame sizes)............................................. 53
Pressure Compensator Override (PCOR)..........................................................................................................................54
Options EPA1, EQA1: pressure compensator configuration with Brake Pressure Defeat.............................. 55
Options EPA2, EQA2: pressure compensator configuration without Brake Pressure Defeat....................... 55
Options L1B1, L2B1, L7B1 – electrohydraulic proportional control for 51 (all frame sizes)................................ 56
L1B1, L2B1, L7B1 solenoid connectors..............................................................................................................................57
Options D7M1, D8M1 – electrohydraulic proportional control with PCOR and hydraulic BPD for 51
(all frame sizes)........................................................................................................................................................................58
Options D7M1, D8M1: pressure compensator configuration with hydraulic Brake Pressure Defeat........59
D7M1, D8M1 solenoid connector..................................................................................................................................59
Options HS** – hydraulic proportional control for 51 (all frame sizes)...................................................................... 60
Pressure Compensator OverRide (PCOR).........................................................................................................................60
Option HSA1: pressure compensator configuration with Brake Pressure Defeat.............................................61
Option HSA2: pressure compensator configuration without Brake Pressure Defeat......................................61
Option HZB1 – hydraulic proportional control for 51 (all frame sizes).......................................................................62
General dimensions – frame size 060
SAE flange design per ISO 3019/1............................................................................................................................................64
DIN flange design per ISO 3019/2............................................................................................................................................67
Cartridge flange..............................................................................................................................................................................70
General dimensions – frame size 080
SAE flange design per ISO 3019/1............................................................................................................................................73
DIN flange design per ISO 3019/2............................................................................................................................................76
Cartridge flange..............................................................................................................................................................................79
General dimensions – frame size 110
SAE flange design per ISO 3019/1............................................................................................................................................82
DIN flange design per ISO 3019/2............................................................................................................................................85
Cartridge flange..............................................................................................................................................................................88
General dimensions – frame size 160
SAE flange design per ISO 3019/1............................................................................................................................................91
DIN flange design per ISO 3019/2............................................................................................................................................93
Cartridge flange..............................................................................................................................................................................95
General dimensions – frame size 250
SAE flange design per ISO 3019/1............................................................................................................................................97
Dimension – Controls
Options TA** for 51-1 – Pressure Compensator Control (Frame Size: 060, 080, 110)........................................... 99
Options TA** for 51 – Pressure Compensator Control (Frame Size: 160, 250)...................................................... 100
Options TH** for 51-1 – Hydraulic Two-Position Control (Frame Size: 060, 080, 110)........................................101
Options TH** for 51 – Hydraulic Two-Position Control (Frame Size: 160, 250).....................................................102
Options E*B1, F*B1 for 51-1 – Electrohydraulic Two-Position Control (Frame Size: 060, 080, 110)...............103
Options E*A5, F*A5 for 51 – Electrohydraulic Two-Position Control (Frame Size: 160, 250)........................... 104
Options T1**, T2**, T7** for 51-1 – Electrohydraulic Two-Position Control (Frame Size: 060, 080, 110).....105
Options T1C2, T2C2 for 51 – Electrohydraulic Two-Position Control (Frame Size: 060, 080, 110)................. 106
Options EPA1, EQA1 for 51 – Electrohydraulic Two-Position Control (All Frame Sizes).................................... 107
Options L1B1, L2B1, L7B1 for 51 – Electrohydraulic Two-Position Control (All Frame Sizes).......................... 108
Options D7M1, D8M1 for 51 – Electrohydraulic Two-Position Control (Frame Size: 060, 080, 110)............. 109
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Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Contents
Options D7M1, D8M1 for 51 – Electrohydraulic Two-Position Control (Frame Size: 160, 250).......................110
Option HSA* for 51 – Hydraulic Proportional Control (All Frame Sizes)..................................................................111
Option HZB1 for 51 – Hydraulic Proportional Control (All Frame Sizes)................................................................. 112
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Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors

Series 51 general information

Series 51 and 51-1 variable displacement motors are bent axis design units, incorporating spherical pistons.
These motors are designed primarily to be combined with other products in closed circuit systems to transfer and control hydraulic power. Series 51 and 51-1 motors have a large maximum / minimum displacement ratio (5:1) and high output speed capabilities. SAE, cartridge, and DIN flange configurations are available.
A complete family of controls and regulators is available to fulfill the requirements of a wide range of applications.
Motors normally start at maximum displacement. This provides maximum starting torque for high acceleration.
The controls may utilize internally supplied servo pressure. They may be overridden by a pressure compensator which functions when the motor is operating in motor and pump modes. A defeat option is available to disable the pressure compensator override when the motor is running in pump mode.
The pressure compensator option features a low pressure rise (short ramp) to ensure optimal power utilization throughout the entire displacement range of the motor. The pressure compensator is also available as a stand-alone regulator.
The series 51 and 51-1 motors – Advanced technology
The most technically advanced hydraulic units in the industry
SAE, cartridge, and DIN flange motors
Cartridge motors designed for direct installation in compact planetary drives
Large displacement ratio (5:1)
Complete family of control systems
Proven reliability and performance
Optimum product configurations
Compact, lightweight
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3
7
1
5
121094 8
P001196
11
2
6
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Series 51 general information

Sectional view of Series 51, proportional control

Series 51 with electric proportional control
Legend:
1 – Piston 2 – Flange 3 – Servo piston 4 – Electric proportional control 5 – Synchronizing shaft 6 – Speed sensor 7 – Charge pressure relief valve 8 – Minimum displacement limiter 9 – Valve segment 10 – Bearing plate 11 – Speed pickup ring 12 – Tapered roller bearings
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P001831
3
7
1
5
12109
4
8
11
2
6
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Series 51 general information

Sectional view of Series 51-1, two-position control

Series 51 with electrohydraulic two-position control
Legend:
1 – Piston 2 – Flange 3 – Servo piston 4 – Electrohydraulic two-position control 5 – Synchronizing shaft 6 – Speed sensor 7 – Charge pressure relief valve 8 – Minimum displacement limiter 9 – Valve segment 10 – Bearing plate 11 – Speed pickup ring 12 – Tapered roller bearings
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Multi-function valve
Synchronizing shaft
Pump swashplate
Servo control cylinder
Servo control cylinder
Reversible variable displacement pump
Input shaft
Heat exchanger
Loop flushing valve
Charge pump
Orificed check valve
Multi-function valve
Charge pressure relief valve
Servo pressure relief valves
to pump case
P001 175E
Control handle
Displacement control valve
Heat exchanger Bypass valve
Reservoir
Vacuum gauge
Hydraulic two-position control
Bent axis variable displacement motor
Output shaft
Case drain fluid
Working loop (High pressure)
Working loop (Low pressure)
Loop flushing relief valve
Servo pressure
Suction
to motor case
max. disp.
T1
T7 T8
T2
T3
M
M7
Signal pressure supply
X1
L1
BB
L2
M2
M1
M4
M5
M3
L2
M4
M3
N
M1
M5
M2
A A
S
n
P001833E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Series 51 general information

Pictorial diagram

System circuit diagram

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Above schematic shows the function of a hydrostatic transmission using a Series 90 Axial Piston Variable Displacement Pump with manual displacement control (MA) and a Series 51 Bent Axis Variable Displacement Motor with hydraulic two-position control (HZ).
Made in Germany
Serial No.
Model Code
Model No./Ident. No.
Neumünster/Germany
Place of manufacture
Ident number
Serial number
Model code
Barcode serial number
P001 832E
5084092
51V080 RS1N L1B1 WB31 ADA 051AAF0 D400
N982211215
508 4092
Made in Germany
Serial No.
Model Code
Model No./Ident. No.
Neumünster/Germany
Place of manufacture
Ident number
Serial number
Model code
Barcode serial number
P001 832E
511685
51D110-1-RD4N E1B1 NNU2 ADD 030AAA3 0000
N973212355
511 685
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Series 51 general information

Series 51/51-1 name plates

Series 51 name plate
Series 51-1 name plate
10 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors

Technical specifications

General specifications

Most specifications for bent axis variable displacement motors are listed on these pages. For definitions of the various specifications, see the related pages in this publication. Not all hardware options are available for all configurations; consult the series 51 and 51-1 model code supplement or price book for more information.
General specifications
Design
Direction of rotation
Recommended installation
Other system requirements

Specific data

Physical properties
Features Unit
Maximum
Displacement
Minimum
Theor. flow at max. displ.
Theor. corner power at rated speed and max. working pressure (Δp = 450 bar [6527 psi])
Theoretical torque
Mass moment of inertia of rotating components
Rated speed
Maximum
*
speed
*
Contact Danfoss representative for max. speed at displacements between max. and min. displacement.
at rated speed at max. speed
at max. displ.
at min. displ.
at max. displ.
at min. displ.
at max. displ.
at min. displ.
Axial piston motor with variable displacement, bent axis design
Clockwise and counter-clockwise (bi-directional)
Discretionary, the housing must always be filled with hydraulic fluid
Independet braking system, circuit overpressure protection, suitable reservoir
Size
060 080 110 160 250
cm3 [in3]
l/min [US gal/min]
kW [hp]
N•m/bar [lbf•in/1000 psi]
2
kg•m [slug•ft2]
min-1(rpm)
60.0 [3.66] 80.7 [4.92] 109.9 [6.71]
12 [0.73] 16.1 [0.98] 22 [1.34] 32.2 [1.96] 50.0 [3.05]
216 [57] 250 [66] 308 [81] 402 [106] 550 [145]
264 [71] 323 [85] 396 [105] 515 [136] 675 [178]
252 [338]
0.95
[583]
0.19
[117]
0.0046
[0.1092]
3600 3100 2800 2500 2200
5600 5000 4500 4000 3400
4400 4000 3600 3200 2700
7000 6250 5600 5000 4250
300 [402]
1.28 [784]
0.26 [156]
0.0071 [0.1685]
371 [498]
1.75 [1067]
0.35 [214]
0.0128 [0.3037]
160.9 [9.82]
480 [644]
2.56 [1563]
0.51 [313]
0.0234 [0.5553]
250 [15.26]
638 [856]
3.98 [2428]
0.80 [486]
0.0480 [1.1580]
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Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Technical specifications
System and case pressure
Parameter
Maximum delta

Fluid specifications

System pressure
Case pressure
Fluid specifications
Features Unit
Viscosity
Temperature range
Cleanliness and Filtration
1)
At the hottest point, normally case drain port.
2)
Minimum: cold start, short term t<3 min, p<50 bar, n<1000 rpm.
Maximum
Minimum low
Rated
Maximum (cold start)
Minimum (at rated speed)
Minimum intermittent
Recommended range
Maximum intermittent
Minimum
1)2)
Rated
Maximum intermittent
Required cleanliness per ISO 4406
Efficiency (charge pressure filtration)
Efficiency (suction / return line filtration)
Recommended inlet screen mesh size
Unit
bar [psi]
mm2/s [SUS]
°C [°F]
-
β-ratio
µm 100 – 125
All sizes
480 [7000]
510 [7400]
10 [145]
3 [44]
5 [73]
0.3 [4.35]
All sizes
7 [49]
12-80 [66-366]
1600 [7416]
-40 [-40]
104 [220]
115 [240]
22/18/13
β
= 75 (β10 ≥ 10)
15-20
β
= 75 (β10 ≥ 2)
35-45
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Vg • n
1000 •
v
Qe =
Vg • p •
mh
20 •
Me =
Qe • p •
t
600
=
Me • n
9550
Pe=
n =
Qe • 1000 •
v
V
g
Vg • n
231 •
v
Qe =
Vg • p •
mh
2 •
Me =
Vg • n • p •
t
396 000
Pe=
n =
Qe • 231 •
v
V
g
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Technical specifications

Determination of nominal motor size

Based on SI units Based on US units
Where:
Q
Input flow (l/min)
e
M
Output torque (N•m)
e
P
Output power (kW)
e
n Speed (min-1) V
Motor displacement per rev. (cm3/rev)
g
p
High pressure (bar)
high
p
Low pressure (bar)
low
∆p High pressure minus Low pressure (bar) η
Motor volumetric efficiency
v
η
Mechanical-hydraulic efficiency
mh
η
Motor total efficiency (ηv • ηmh)
t
Where:
Q
Input flow [US gal/min]
e
M
Output torque [lb•in]
e
P
Output power [hp]
e
n Speed [rpm] V
Motor displacement per rev. [in3/rev]
g
p
High pressure [psi]
high
p
Low pressure [psi]
low
∆p High pressure minus Low pressure [psi] η
Motor volumetric efficiency
v
η
Mechanical-hydraulic efficiency
mh
η
Motor total efficiency (ηv • ηmh)
t
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W
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors

General technical specifications

Case pressure

Under normal operating conditions, case pressure must not exceed the rated pressure. Momentary case pressure exceeding this rating is acceptable under cold start conditions, but still must stay below the maximum pressure rating.
The minimum pressure provides proper lubrication at high speeds. Operation with case pressure in excess of these limits may result in external leakage due to damage to
seals, gaskets, and/or housings.
Case pressure
Parameter
Rated
Case pressure

Speed range

Rated speed is the speed limit recommended at full power condition and is the highest value at which
normal life can be expected. Maximum speed is the highest operating speed permitted and cannot be exceeded without reduction
in the life of the product or risking immediate failure and loss of driveline power (which may create a safety hazard). In the range between rated and maximum speed please contact your Danfoss Power Solutions representative.
Maximum (cold start)
Minimum (at rated speed)
Unit
bar [psi]
All sizes
3 [44]
5 [73]
0.3 [4.35]
Warning
The loss of hydrostatic drive line power in any mode of operation (e.g., forward, reverse, or “neutral”) may cause the loss of hydrostatic braking capacity. A braking system, redundant to the hydrostatic transmission must, therefore, be provided which is adequate to stop and hold the system should the condition develop.
Speed limits
Features Unit
at max. displ.
Rated speed
at min. displ.
min-1(rpm)
at max. displ.
Maximum speed
at min. displ.
060 080 110 160 250
3600 3100 2800 2500 2200
5600 5000 4500 4000 3400
4400 4000 3600 3200 2700
7000 6250 5600 5000 4250
Size
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Rated speed at min. displacement
Rated speed at max. displacement
Acceptable operating range
Maximim speed at min. displacement
Maximum speed at max. displacement
Curve determined by rated flow
Min. displacement Max. displacement
P001 781E
Speed min
-1
(rpm)
Motor angle (degrees)
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications
Speed limits
For operation within the range above the acceptable range contact Danfoss Power Solutions representative.

Pressure limits

System pressure is the dominant operating variable affecting hydraulic unit life. High pressure, which results from high load, reduces expected life in a manner similar to the affects of high load on other mechanical assemblies such as engines and gear boxes. There are load-to-life relationships for the rotating group and for the shaft anti-friction bearings.
Continuous pressure is the pressure at which the hydrostatic system could operate continuously and still achieve acceptable hydrostatic life. This pressure level varies depending on operating speed, and on the life requirements for a particular application. While most mobile applications require system pressure to vary widely during operation, a “weighted average” pressure can be derived from a machine duty cycle. (A duty cycle is a means of quantifying the pressure and speed demands of a particular system on a percent time basis). Once a duty cycle has been determined or estimated for a specific application, contact your Danfoss representative for system life ratings for the application.
Maximum delta pressure is the highest intermittent pressure allowed, and is the relief valve setting. It is determined by the maximum machine load demand. For most systems, the load should move at this pressure.
Maximum pressure is assumed to occur a small percentage of operating time, usually less than 2 % of the total. Both the continuous and maximum pressure limits must be satisfied to achieve the expected life.
Minimum low pressure must maintained under all operating conditions to avoid cavitation.
System pressure range, input
Maximum delta pressure Minimum low pressure Maximum pressure
480 [7000 psi] 10 [145 psi] 510 [7400 psi]
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W
Loop flushing relief valve
Loop flushing shuttle spool
P001 782E
A B
P001 830
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Loop flushing

An integral non-adjustable loop flushing valve is incorporated into all these motors. Installations that require fluid to be removed from the low pressure side of the system circuit because of cooling requirements or contamination removal will benefit from loop flushing.
The integral loop flushing valve is equipped with an orificed charge pressure relief valve designed with a cracking pressure of 16 bar [232 psi].
Valves are available with several orifice sizes to meet the flushing flow requirements of all system operating conditions.
The total system charge pump flow should be of sufficient volume to accommodate:
The number of motors in the system
System efficiency under worst case conditions
Pump control requirements
External needs
Although charge pump sizing requires the consideration of many system variables, the following table gives a recommendation of what charge pump displacement may be required to accommodate the flushing flow of each available charge relief valve orifice.
Recommended charge pump displacement
Loop flushing valve E4, E6 F0 F3 G0 G3 H0
Charge pump size (cm3) 8 11 14 17 or 20 26 34, 47 or 65
Warning
The loss of hydrostatic drive line power in any mode of operation (e.g., forward, reverse, or “neutral” mode) may cause the loss of hydrostatic braking capacity. A braking system, redundant to the hydrostatic transmission must, therefore, be provided which is adequate to stop and hold the system should the condition develop.
Loop flushing valve
Hydraulic schematic
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0 5
[1.3]10[2.6]15[4.0]20[5.3]
Case flow l/min [US gal/min]
Low system pressure minus case pressure
bar [psi]
25
[6.6]30[8.0]35[9.2]40[10.6]
[508]
35
[363]
25
[218]
15
[73]
5
P001 860E
E4 E6 F0 F3 G0 G3 H0
C
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications
Case flow characteristic
Equation:
Where:
Q
– flushing flow per motor
Flush
Q
– charge flow at operating speed
Charge
kMo – number of motors feeded by one pump Q
– sum of external leakages
Leak

Minimum displacement limiter

Hydraulic fluids

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Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 17
Q
includes:
Leak
motor leakage
pump leakage + internal consumers:
8 l/min [2.11 US gal/min] for displacement control pumps or
for non-feedback controlled pumps at 200 bar [2900 psi]
external consumers:
e.g. brakes, cylinders, and other pumps
All Series 51 and 51-1 motors incorporate mechanical displacement limiters. The minimum displacement of the motor is preset at the factory with a set screw in the motor housing. A
tamper-proof cap is provided.
Ratings and data are based on operating with hydraulic fluids containing oxidation, rust and foam inhibitors. These fluids must possess good thermal and hydrolytic stability to prevent wear, erosion and corrosion of the internal components.
Fire resistant fluids are also suitable at modified operating conditions. Please see Danfoss literature Technical Information Hydraulic Fluids and Lubricants for more information.
For more information contact your Danfoss representative.
Caution
It is not permissible to mix hydraulic fluids.
Suitable hydraulic fluids:
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications
Hydraulic fluids per DIN 51 524, part 2 (HLP)
Hydraulic fluids per DIN 51 524, part 3 (HVLP)
API CD, CE and CF engine fluids per SAE J183
M2C33F or G automatic transmission fluids (ATF)
Agricultural multi purpose oil (STOU)
Premium turbine oils (for Premium turbine oils contact your Danfoss representative).

Temperature and viscosity

Temperature and viscosity requirements must be concurrently satisfied. The data shown in the tables assume petroleum-based fluids, are used.
The high temperature limits apply at the hottest point in the transmission, which is normally the motor case drain. The system should generally be run at or below the rated temperature. The maximum temperature is based on material properties and should never be exceeded.
Cold oil will generally not affect the durability of the transmission components, but it may affect the ability to flow oil and transmit power; therefore temperatures should remain 16 °C [30 °F] above the pour point of the hydraulic fluid. The minimum temperature relates to the physical properties of component materials.
For maximum unit efficiency and bearing life the fluid viscosity should remain in the recommended operating range. The minimum viscosity should be encountered only during brief occasions of maximum ambient temperature and severe duty cycle operation. The maximum viscosity should be encountered only at cold start.
Heat exchangers should be sized to keep the fluid within these limits. Testing to verify that these temperature limits are not exceeded is recommended.

Filtration system

Viscosity and temperature range
Features Unit
Minimum intermittent
Viscosity
Temperature range
1)
At the hottest point, normally case drain port.
2)
Minimum: cold start, short term t<3 min, p<50 bar, n<1000 rpm.
Recommended range
Maximum intermittent
Minimum
1)2)
Rated
Maximum intermittent
mm2/s [SUS]
°C [°F]
All sizes
7 [49]
12-80 [66-366]
1600 [7416]
-40 [-40]
104 [220]
115 [240]
To prevent premature wear, ensure that only clean fluid enters the hydrostatic transmission circuit. A filter capable of controlling the fluid cleanliness to ISO 4406, class 22/18/13 (SAE J1165) or better, under normal operating conditions, is recommended.These cleanliness levels cannot be applied for hydraulic fluid residing in the component housing/case or any other cavity upon delivery from the factory.
The filter may be located on the pump (integral) or in another location (remote or suction). The integral filter has a filter bypass sensor to signal the machine operator when the filter requires changing. Filtration strategies include suction or pressure filtration. The selection of the filter strategy depends on a number of factors including the contaminant ingression rate, the generation of contaminants in the system, the required fluid cleanliness, and the desired maintenance interval. Filters are selected to meet the above requirements using rating parameters of efficiency and capacity.
Filter efficiency can be measured with a Beta ratio (βX). For simple suction-filtered closed circuit transmissions and open circuit transmissions with return line filtration, a filter with a β-ratio within the
18 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
C
W
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Fluid selection

range of β
= 75 (β10 ≥ 2) or better has been found to be satisfactory. For some open circuit systems,
35-45
and closed circuits with cylinders being supplied from the same reservoir, a higher filter efficiency is recommended. This also applies to systems with gears or clutches using a common reservoir. For these systems, a charge pressure or return filtration system with a filter β-ratio in the range of β
= 75 (β10 ≥
15-20
10) or better is typically required. Because each system is unique, only a thorough testing and evaluation program can fully validate the
filtration system. For more information, see Design Guidelines for Hydraulic Fluid Cleanliness, Technical Information BC00000095.
Filter βx-ratio is a measure of filter efficiency defined by ISO 4572. It is defined as the ratio of the number of particles greater than a given diameter (“x” in microns) upstream of the filter to the number of these particles downstream of the filter.
Filtration, cleanliness level and βx-ratio (recommended minimum)
Cleanliness per ISO 4406
Efficiency βx (charge pressure filtration)
Efficiency βx (suction and return line filtration)
Recommended inlet screen mesh size
22/18/13
β
= 75 (β10 ≥ 10)
15-20
β
= 75 (β10 ≥ 2)
35-45
100 – 125 µm
Ratings and performance data are based on operating with hydraulic fluids containing oxidation, rust and foam inhibitors. These fluids must possess good thermal and hydrolytic stability to prevent wear, erosion, and corrosion of motor components.

Reservoir

Independent braking system

Caution
Never mix hydraulic fluids of different types.
Fire resistant fluids are also suitable at modified operating conditions. For more information, see Hydraulic Fluids and Lubricants, Technical Information BC00000093.
The function of the reservoir is to remove air and to provide make up fluid for volume changes associated with fluid expansion or contraction, possible cylinder flow, and minor leakage.
The reservoir should be designed to accommodate maximum volume changes during all system operating modes and to promote deaeration of the fluid as it passes through the tank.
A minimum reservoir volume equal to 1/2 to 1 1/2 times charge pump flow/min is suggested. This allows 30 seconds fluid dwell for removing entrained air at the maximum return flow. This is usually adequate to allow for a closed reservoir (no breather) in most applications. The reservoir outlet to the charge pump inlet should be above the bottom of the reservoir to take advantage of gravity separation and prevent large foreign particles from entering the charge inlet line.
The reservoir inlet (fluid return) should be positioned so that the flow to the reservoir is discharged below the normal fluid level, and also directed into the interior of the reservoir for maximum dwell and efficient deaeration.
Warning
The loss of hydrostatic drive line power in any mode of operation (e.g., forward, reverse, or “neutral” mode) may cause the loss of hydrostatic braking capacity. A braking system, redundant to the hydrostatic transmission must, therefore, be provided which is adequate to stop and hold the system should the condition develop.
©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 19
L1 • 1500
n
2
L2 =
hours
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Motor bearing life

The rated motor bearing life L bearings, when operating at a speed of n = 1500 min-1 (rpm) with a charge pressure of 20 bar [290 psi] and without external shaft load.
h10
shown in the table below is based on a 90 % survival rate of shaft
The rated motor bearing life L
Frame Size Effective ∆ pressure
bar [psi]
140 [2030] 19 800 18 530 16 370
060
080
110
160
250
210 [3050] 6320 5960 5340 280 [4060] 2740 2600 2350 140 [2030] 14 420 13 580 12 120 210 [3050] 4610 4370 3960 280 [4060] 2000 1910 1750 140 [2030] 15 800 14 890 13 330 210 [3050] 5040 4790 4350 280 [4060] 2180 2090 1920 140 [2030] 15 670 14 770 13 200 210 [3050] 5005 4750 4300 280 [4060] 2170 2070 1900 140 [2030] 11 760 11 130 10 020 210 [3050] 3750 3580 3260 280 [4060] 1630 1560 1440
h10
(hours)
Motor angle
15° 32°
Lifetimes for speeds other than 1500 min-1 (rpm) can be calculated from:
Where: Units:
L
==Rated L10 life at 1500 min-1 (rpm)
1
n
2
Operating speed
hours min-1 (rpm)
Contact your Danfoss Power Solutions representative for bearing life values at other pressure and angle.
20 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
Fr
35°
35°
Fr
A
X
1
A
A
SAE-Flange design per ISO 3019/1
DIN-Flange design per ISO 3019/2
Cartridge Flange design
35°
35°
Fa
Fa
Fa
X
1
Fr
X
1
X2 < X
1
X2 > X
1
X2 < X
1
X2 > X
1
X2 < X
1
X2 > X
1
P001 166E
35°
Fr
Fr
Fr
35°
OPTIMUM LOAD ORIENTATION
OPTIMUM LOAD ORIENTATION
OPTIMUM LOAD ORIENTATION
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

External shaft loads

Series 51 and 51-1 motors are designed with bearings that can accept external radial and thrust loads. The external radial shaft load limits are a function of the load position, the load orientation, and operating
conditions of the unit.

External shaft load orientation

©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 21
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Radial and thrust loads to the output shaft

The table below provides the following information:
The maximum allowable radial load (Fr) based on the distance (X1) from the mounting flange to the load.
The maximum allowable axial load (Fa).
The actual distance of Fr for a given application from the mounting flange to the load (X2).
The basic distance (A).
Fa/∆p ratio of allowable axial load, dependent upon the system pressure.
Radial and thrust loads to the output shaft
Feature Symbol Unit
Maximum allowable radial load
Max. allow. axial load at zero rpm, or running in the idle pressure
Max. allowable bending moment
Max. allowable axial load at pressure
Distance SAE mounting flange
Distance DIN mounting flange 57.2
Distance Cartridge mount. flange 117.6
Basic distance A 25.2
– = not available
060 080 110 160 250
Fr
Fa 1100
M
Fa/∆p
X
1
N [lb]
N•m [lb•in]
N/bar [lb/1000 psi]
mm [in]
10 000 [2248]
[247]
252 [2230]
10.4 [161]
33.6 [1.32]
[2.25]
[4.63]
[0.99]
12 000 [2698]
1400 [315]
307 [2717]
12.6 [195]
33.6 [1.32]
57.6 [2.27]
136.1 [5.36]
25.6 [1.01]
Frame Size
14 000 [3147]
1800 [405]
766 [6780]
15.2 [236]
62.7 [2.47]
94.7 [3.73]
177.5 [7.0]
54.7 [2.15]
18 000 [4047]
2500 [562]
805 [7125]
19.2 [298]
52.7 [2.07]
84.7 [3.33]
44.7 [1.76]
26 000 [5845]
4500 [1012]
970 [8585]
26.4 [409]
45.3 [1.78]
37.3 [1.47]
The values in the table are maximum values and are not allowed under continuous load conditions.
Allowable external shaft load, when shaft load distance is different from standard
Use this formula to calculate maximum allowable radial load when max. shaft load distance X2 is different from X1:
Metric system: Inch system:
Metric or Inch system:
X2 > X1 Fr = Fr
max
N [lbf]
X2 is the actual distance of Fr from the mounting flange to the load for a given application. If X2< X1, Fr
could also be calculated by the first equation, but in addition the bearing life has to be checked.
Contact your Danfoss representative for load ratings of specific shafts or when the load orientation deviates more than 35° in either direction from the optimum.
22 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
Efficiency
%
v
o
l
u
m
e
t
r
i
c
e
f
f
i
c
i
e
n
c
y
η
v
=
2
1
0
b
a
r
[
3
0
5
0
p
s
i
]
100
95
90
85
80
0
25
50
75
100
Speed % of rated speed
P001 155E
η
t
=
4
2
0
b
a
r
[
6
0
9
0
p
s
i
]
t
o
t
a
l
e
f
f
i
c
i
e
n
c
y
η
t
=
2
1
0
b
a
r
[
3
0
5
0
p
s
i
]
η
v
=
4
2
0
b
a
r
[
6
0
9
0
p
s
i
]
Speed% of rated speed
0
System pressure bar [psi]
420
[6090]
280
[4060]
140
[2030]
0
25
50
75
100
74.5%
84.5%
90.5%
93.5%
94.5%
P001 137E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Efficiency graphs and maps

This graph provides the volumetric and overall efficiencies for a typical Series 51 and 51-1 motor operating at maximum displacement, system pressures of 210 and 420 bar [3050 and 6090 psi], and a fluid viscosity of 8.2 mm²/s [53 SUS]. These efficiencies can be used for all frame sizes.
Overall and volumetric efficiency at maximum displacement
This graph shows typical overall efficiencies for Series 51 and 51-1 motors operating at maximum displacement and system pressures up to 420 bar [6090 psi], and a fluid viscosity of 8.2 mm²/s [53 SUS]. These efficiencies can be used for all frame sizes.
Overall efficiency at maximum displacement
This graph shows typical overall efficiencies for Series 51 and 51-1 motors operating at 30% of maximum displacement and system pressures up to 420 bar [6090 psi], and a fluid viscosity of 8.2 mm²/s (53 SUS). These efficiencies can be used for all frame sizes.
©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 23
80
η
v
=
4
2
0
b
a
r
[
6
0
9
0
p
s
i
]
v
o
l
u
m
e
t
r
i
c
e
f
fi
c
i
e
n
c
y
η
v
=
2
1
0
b
a
r
[
3
0
5
0
p
s
i
]
η
t
=
4
2
0
b
a
r
[
6
0
9
0
p
s
i
]
25 50
75
1000
60
65
70
75
85
90
95
100
Efficiency %
Speed % of rated speed
o
v
e
r
a
l
l
e
f
fi
c
i
e
n
c
y
η
t
=
2
1
0
b
a
r
[
3
0
5
0
p
s
i
]
P001 156E
Speed % of rated speed
0
System pressure bar [psi]
420
[6090]
280
[4060]
140
[2030]
0
25
50
75
100
P001 138E
61%
71%
77%
80%
81%
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications
Overall and volumetric efficiency at 30% of maximum displacement
This graph shows typical overall efficiencies for Series 51 and 51-1 motors operating at 30% of maximum displacement and system pressures up to 420 bar [6090 psi], and a fluid viscosity of 8.2 mm²/s (53 SUS). These efficiencies can be used for all frame sizes.
Overall efficiency at 30% of maximum displacement
24 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
P001 492
Turck Eurofast Connector
4 pin
(Supplied connector)
IP Rating (DIN 40 050) IP 67
Mating connector
straight right angle
No.: K14956 No.: K14957
Id.-No.: 500724 Id.-No.: 500725
P001 755E
1
2
3
4
Keyway (Ref)
Red White Black Green
P002 108E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications

Speed sensor

An optional speed sensor for direct measurement of speed is available. This sensor may also be used to sense the direction of rotation. A special magnetic speed pick-up ring is pressed onto the outside diameter of the shaft and a Hall effect sensor is located in the motor housing. The sensor accepts supply voltage and outputs a digital pulse signal in response to the speed of the ring. The output changes its high/low state as the north and south poles of the permanently magnetized speed ring pass by the face of the sensor. The digital signal is generated at frequencies suitable for microprocessor based controls. The sensor is available with different connectors (see below). The SAE and DIN flange motors use a flat end speed sensor. The cartridge flange motors use a conical end speed sensor.
Data magnetic speed pick-up ring
Frame size
Pulze/Rev 45 49 54 61 71
Speed sensor technical data
Supply voltage Supply voltage regulated Required current Maximum current Maximum frequency Voltage "high" Voltage "low" Temperature range
1)
It is not acceptable to energize the 4.5-8.5 VDC speed sensor with 12 VDC battery voltage; it must be energized by a regulated power supply. If it is desirable to energize the sensor with battery voltage, contact your Danfoss representative for an optional speed sensor.
1)
060 080 110 160 250
4.5 – 8.5 V
15 VDC max.
12 mA at 5 VDC (no load)
20 mA at 5 VDC and 1 Hz
15 kHz
Supply voltage -0.5 VDC min.
0.5 VDC max.
-40 to 110 °C [-40 to 230 °F]
DC
©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 25
Speed sensor with Turck Eurofast 4-pin connector
Pin 1 or A: Supply voltage Pin 2 or B: Direction of rotation Pin 3 or C: Speed signal, digital Pin 4 or D: Ground common
Speed sensor with Packard Weather-Pack 4-pin connector
A B C
D
Packard Weather-Pack
4 pin
(Supplied Connector)
Mating Connector
No.: K03379
Id.-No.: 505341
P001 758E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
General technical specifications
Contact your Danfoss representative for more information.

Typical control and regulator applications

Application Control / Regulators
without PCOR with PCOR with PCOR and BPD
N1 HZ E1, E2, E7 EP, EQ F1, F2 L1, L2, L7 TA T1, T2 TH HS TA T1, T2 EP, EQ D7, D8 HS
Wheel loader
Roller compactor
Paver wheeled
Paver tracked
Sweeper
Trencher
Excavator wheeled
Fork lift truck
Agricultural
Forestry
Telehandler
Railroad
Snow groomer
Snow blower
Crane
1)
1)
1)
1)
1)
1)
1)
1)
1)
1)
1)
1)
1)
2)
3)
Suitable configuration
1)
Propel function
2)
Blow drive function
3)
Winch function
The table above is provided to assist in selecting controls and regulators for various applications. These recommendations are based on experience with a wide range of applications.
Contact your Danfoss Power Solutions representative for more information on control selection.
26 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
X1
(M3)
M5
B
M4
L1
N
L2
A
P001 779E
n
min.
disp.
T3
T2
System pressure bar [psi]
Servo pressure bar [psi]
0
0
200
[2900]
100
[1450]
10
[145]
20
[290]
30
[435]
300
[4350]
400
[5800]
minimum servo pressure under all conditions
P001 877E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors

Controls circuit diagram – nomenclature – description

Option N1NN – hydraulic two-position control for 51-1 (frame size: 060, 080, 110)

A, B = Main pressure lines L1, L2 = Drain lines M4 = Gauge port servo pressure M5 = Gauge port servo supply pressure X1 (M3) = Control pressure T1, T2, T3 = Optional orifices N = Speed sensor
Displacement changes from maximum displacement to minimum displacement position, under load, as control pressure at port X1 (M3) is equal to low pressure or higher.
Control pressure on port X1 (M3)
No pressure on port = maximum displacement Control pressure on port = minimum displacement Maximum control pressure = 50 bar [725 psi]
The graph shows the necessary external and internal (= low system pressure) control pressure X1, which is needed to stroke the motor depending on high system pressure.
Control N1NN necessary control pressure
©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 27
P001 875E
min
max
Control pressure
Displacement
T8T3T7
T1
T2
max. disp.
M2
X1
M7
B
M5
L1
M1
M4L2
A
M3 N
P100 177E
n
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Controls circuit diagram – nomenclature – description
Control operation N1NN
Not all control options are shown in this Technical Information. Contact your Danfoss representative for special control functions.

Option HZB1 – hydraulic two-position control for 51 (frame size: 160, 250)

A, B = Main pressure lines L1, L2 = Drain lines M1, M2 = Gauge port for A and B M3, M4 = Servo pressure M5 = Gauge port servo supply pressure internal M7 = Gauge port control pressure X1 = Control pressure T1, T2, T3, T7, T8 = Optional orifices N = Speed sensor
Displacement can be changed hydraulically under load from minimum displacement to maximum displacement and vice versa by control pressure to port X1. For proportional control see Option HZB1 –
hydraulic proportional control for 51 (all frame sizes) on page 62
Control pressure on port X1
28 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
P100 179E
Control pressure Δ bar [psi]
0
3
[44]
min
max
Displacement
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Controls circuit diagram – nomenclature – description
No pressure on port = maximum displacement Control pressure on port = minimum displacement Maximum control pressure = 50 bar [725 psi] The standard control start point setting = 3 bar [44 psi]
Control operation HZB1
Not all control options are shown in this Technical Information. Contact your Danfoss representative for special control functions.
©
Danfoss | October 2017 520L0440 | BC00000018en-US0401 | 29
M3
T3
M3 with Electric brake pressure defeat
with Hydraulic brake pressure defeat
without Brake pressure defeat
XB
XA
T3
M3
T3
min. disp.
n
B
A
L1
M4
L2
N
P001 834E
min max
Displacement
Ramp < 10 bar
[145 psi]
Regulator start
Setting range
130
[1890]
370
[5370]
System pressure Δ p bar [psi]
P001 173E
Technical Information
Series 51 and 51-1 Bent Axis Variable Displ. Motors
Controls circuit diagram – nomenclature – description

Options TA** – pressure compensator control for 51-1 (frame size: 060, 080, 110)

Circuit diagram–motor with pressure compensator control TA**
Ports:
A, B = Main pressure lines L1, L2 = Drain lines M3, M4 = Servo pressure XA, XB = Control pressure port brake pressure defeat (BPD) T3 = Orifice N = Speed sensor
Displacement is regulated automatically between minimum and maximum displacement in response to system pressure.
Regulator start = minimum displacement Regulator end = maximum displacement Regulator start pressure is adjustable from 130 to 370 bar [1890 to 5370 psi]. Pressure ramp from regulator start pressure (with motor at minimum displacement) until maximum
displacement is reached is less than 10 bar [145 psi]. This ensures optimal power utilization throughout the entire displacement range of the motor.
Control operation TA**
30 | © Danfoss | October 2017 520L0440 | BC00000018en-US0401
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