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
System circuit diagram...................................................................................................................................................................9
Series 51/51-1 name plates........................................................................................................................................................ 10
Technical specifications
General specifications.................................................................................................................................................................. 11
Specific data.....................................................................................................................................................................................11
Determination of nominal motor size....................................................................................................................................13
General technical specifications
Case pressure...................................................................................................................................................................................14
Temperature and viscosity......................................................................................................................................................... 18
Filtration system ............................................................................................................................................................................18
Motor bearing life.......................................................................................................................................................................... 20
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
Typical control and regulator applications...........................................................................................................................26
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
SAE flange design per ISO 3019/1............................................................................................................................................73
DIN flange design per ISO 3019/2............................................................................................................................................76
SAE flange design per ISO 3019/1............................................................................................................................................82
DIN flange design per ISO 3019/2............................................................................................................................................85
SAE flange design per ISO 3019/1............................................................................................................................................91
DIN flange design per ISO 3019/2............................................................................................................................................93
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
Danfoss | October 2017520L0440 | BC00000018en-US0401 | 5
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
Danfoss | October 2017520L0440 | BC00000018en-US0401 | 9
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 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
FeaturesUnit
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
Danfoss | October 2017520L0440 | BC00000018en-US0401 | 13
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.
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 pressureMinimum low pressureMaximum pressure
Danfoss | October 2017520L0440 | BC00000018en-US0401 | 15
W
Loop flushing relief valve
Loop flushing shuttle spool
P001 782E
AB
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 valveE4, E6F0F3G0G3H0
Charge pump size (cm3)8111417 or 202634, 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.
Danfoss | October 2017520L0440 | 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
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 maximumtemperature 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 recommendedoperating 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
FeaturesUnit
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
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, TechnicalInformationBC00000095.
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 InformationBC00000093.
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 2017520L0440 | 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
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
Danfoss | October 2017520L0440 | 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
FeatureSymbol 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 flange57.2
Distance Cartridge mount. flange117.6
Basic distanceA25.2
– = not available
060080110160250
Fr
Fa1100
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.
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 2017520L0440 | 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
]
2550
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.
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/Rev4549546171
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.
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.
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.
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
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.
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.