The carrier needs pull on the ramp and speed on the level. Screen the two jobs at separate displacement settings. At the same inlet flow, the smaller setting gives more rev/min. At the same working-port differential, the larger setting gives more N·m. A variable displacement axial piston motor can cover both duties if the drive supplies each point and the regulator shifts under the intended conditions.
Take four entries from the next shift trace. Write the operator request, the signal at the regulator, the displacement indication or inference, and the measured shaft speed. If the first two change and the third stays put, check control pressure and the applicable override. If speed alone changes, check how much oil reached the motor.
Draw the shift into the machine cycle
Use a yard-to-ramp cycle for the brief. Set a light-travel target on the level and a loaded target on the slope. Include the approach to the slope. If a shift calls for more displacement while the speed target holds, the pump has to meet the higher flow demand at that moment.
Keep the load figures on a common shaft basis. A wheel, drum or gearbox measurement needs the transmission ratio and any loss assumptions beside it. Label direction and power transfer. A loaded descent belongs on a separate braking row. The calculations below apply to motoring.
Duty entry
What belongs in the machine record
Question for the selection
Breakaway
Shaft torque required to initiate motion, available differential pressure and initial command
Which displacement will be available at start?
Loaded running
Sustained speed, torque, duration and oil condition
Does the chosen endpoint have enough torque at the permitted pressure?
Light travel
Maximum demanded shaft speed and measured or available flow
Can the smaller setting run at the expected speed within the manufacturer's envelope?
Shift toward higher torque
Load at the requested shift, permissible speed change and control state
How will the pump and motor respond together?
Deceleration or overrun
Direction of power transfer, brake sequence and permissible motion
Which machine protection and control checks are required?
Loss of command
Expected valve response, brake behavior and permitted movement
Has the machine designer approved the resulting state?
Attach the same duty table to the quotation and the commissioning record. “Fast range available” in a quotation and “fast range achieved while lightly loaded at the specified temperature” in a test sheet describe two different levels of evidence.
Put the two endpoints on the order
Enter both endpoints in cm³/rev. The number gives the nominal swept volume per shaft revolution. Keep speed range, torque range and control position in their own columns.
A display marked HIGH may request high travel speed. In the example that requires the smaller displacement. Write the requested endpoint on the drawing, and label a percentage by its denominator. Half of the motor’s maximum displacement does not necessarily correspond to half of the command range.
Item
Where the value comes from
How it is used
Motor family, size and series
Tag, complete order code and current approved drawing
Identifies the applicable documentation
Maximum displacement
Selected setting and applicable build data
Loaded torque and large-setting speed calculations
Minimum displacement
Selected setting for this build
Speed screening and available torque in the smaller state
Command type and polarity
Regulator symbol and electrical or hydraulic documentation
Determines what a given input requests
Control pressure source
Circuit diagram and regulator instructions
Identifies the source and conditions for actuation
Default and override behavior
Control code plus machine circuit and logic
Defines the state to expect during a command loss or load event
Use the complete build record to fill the two displacement cells. A family range does not specify the fitted minimum stop. If the offer includes a preset, request both configured values, applicable tolerances and the approved adjustment documentation.
The BLINCE A6VM axial piston motor is a variable-displacement candidate. For the actual assembly, request the applicable option code, setting information and operating limits. The examples in this guide use assumed values.
Read the regulator code with the circuit
Two-position hardware commands endpoints. A proportional regulator can request intermediate positions within its control range. For either type, obtain the response requirements separately. The safe shift window depends on what the complete machine does while the regulator moves.
Compare the Y1X and Y2X hydraulic schematics in the Kawasaki M7V regulator section. One changes toward smaller displacement as the pilot signal rises. The other changes toward larger displacement. The same catalog shows how an optional pressure-related function can take precedence over the range request. Kawasaki M7V technical catalog
An H1B electric two-position option with pressure compensator override gives a useful example. Its coil can stay de-energized while rising loop pressure drives displacement upward. Check the complete option code before applying that behavior to a particular unit. Danfoss H1B technical information, October 2025
For the offered BLINCE build, ask for a table that maps each regulator input to its specified displacement. Include the electrical state or external pilot signal, the required source for hydraulic control energy and the applicable pressure-related override. Keep port names and symbols as they appear on the approved drawing. Similar names on two regulators can conceal differences in how the servo receives and exhausts oil.
A state table for the actual control
The following entries form an empty test framework. Fill the expected motor state from the selected code and circuit, then compare the observed state under the approved procedure.
Machine condition
Record at the input
Record at the output
Normal start sequence
Controller request, actual coil input or pilot signal, control supply condition
Achieved range, shaft speed and direction
Request for light-travel range
Time of request and when the corresponding input reaches the regulator
Shift start, settled response and any change in working pressure
Increasing load while range request holds
Same input state plus working-port pressures and override status if observable
Evidence of a move toward another displacement and corresponding speed response
Command removed under an approved verification condition
Input state, hydraulic supply and brake sequence
Resulting displacement or documented inference and machine behavior
Return to loaded range
Request and input timing plus pump response
Speed change, pressure change and repeatability
Put unverified states on the supplier question list. For a loss-of-command check, use the machine designer’s approved procedure or an agreed bench method. Keep any state that could not be safely checked open in the acceptance record.
Work the two endpoints using the same hydraulic inputs
Use an illustrative pair of settings, 120 and 60 cm³/rev. Hold Q at 72 L/min and Δp at 160 bar. Use ηv = 0.90 and ηhm = 0.90 for both rows. Replace these assumed efficiencies with data at the required operating points for real selection.
For the steady motoring estimate, use the following units and terms. This boundary covers the motor's working flow and differential. Account for auxiliary and flushing supplies separately where present.
Term
Equation
Units
Shaft speed n
1,000 × Q × ηv / V
Q in L/min and V in cm³/rev give n in rev/min
Shaft torque T
Δp × V × ηhm / (20π)
Δp in bar and V in cm³/rev give T in N·m
Shaft power
2π × n × T / 60,000
n in rev/min and T in N·m give kW
Input or result
Larger displacement
Smaller displacement
Assumed displacement
120 cm³/rev
60 cm³/rev
Inlet flow and working-port differential
72 L/min, 160 bar
72 L/min, 160 bar
Estimated speed
1,000 × 72 × 0.90 / 120 = 540 rev/min
1,000 × 72 × 0.90 / 60 = 1,080 rev/min
Estimated shaft torque
160 × 120 × 0.90 / (20π) ≈ 275 N·m
160 × 60 × 0.90 / (20π) ≈ 138 N·m
Estimated shaft power
Approximately 15.6 kW
Approximately 15.6 kW
The input row is 160 × 72 / 600 = 19.2 kW. Applying both assumed efficiencies gives 15.55 kW at either setting. For the actual points, check the relevant loss and temperature data. The example holds the efficiency factors constant to expose the speed and torque trade.
Now put 200 N·m in the loaded-duty row. The required differential follows from Δp = 20π × T / (V × ηhm). With only 160 bar available across the working ports, the smaller endpoint cannot support this example load. Keep the machine’s approved protection settings in the selection brief.
Review result for the assumed 200 N·m load
Larger setting
Smaller setting
Required differential
About 116.4 bar
About 232.7 bar
Available differential assumed for comparison
160 bar
160 bar
Margin in this arithmetic
About 43.6 bar
Shortfall of about 72.7 bar
Disposition
Check actual limits and operating evidence
Change the duty or candidate selection before approval
Keep this steady calculation beside the breakaway, stability and acceleration checks. Confirm the applicable rating for each duration.
Use the pressure difference at the motor
Example gauges on the working ports show 185 and 25 bar. Record 185 − 25 = 160 bar in the torque row. If the first gauge is at the pump, account for the pressure drop along the supply path before using it as a motor inlet reading.
The chosen measuring point matters most when the machine changes state. If outlet pressure rises during a shift, a nearly unchanged inlet reading can accompany a lower motor differential. A time record of the two ports can reveal that change while a single peak gauge reading cannot place it in the sequence. The same record needs flow and speed data at useful resolution to distinguish control action from a change elsewhere in the circuit.
The case and drain have their own pressure limits. The difference between the two working ports supplies the torque calculation. Case pressure, outlet pressure and control supply are separate checks with their own locations and definitions. In a closed circuit, use the designated measurement points and the manufacturer or machine documentation for charge and control conditions. Qualified personnel need the approved measurement arrangement, secure loads and instruments rated for the actual circuit.
Test the shift against the pump's available flow
Suppose the controller must hold the shaft at 750 rev/min. Set up a flow column for each displacement and check it against delivery at the motor.
At the same assumed ηv = 0.90, use Q = n × V / (1,000 × ηv).
Endpoint
Calculation at 750 rev/min
Inlet demand
60 cm³/rev
750 × 60 / 900
50 L/min
120 cm³/rev
750 × 120 / 900
100 L/min
At constant speed, the shift toward the large endpoint adds 50 L/min to the assumed motor demand.
At 72 L/min, the large endpoint would settle near 540 rev/min in this model. Check whether the trace shows that endpoint before assigning a fault to the regulator. Retain the speed request, measured inlet delivery and achieved range in the same record.
Proposed response
Evidence required
Allow speed to decrease with load
Expected speed in the larger setting at available flow and permissible machine behavior
Hold speed through the transition
Pump delivery at the changed demand, response timing and available input power
Prevent a shift in a high-load state
Machine logic, approved conditions and observed response when the request is inhibited
Move automatically toward greater torque
Documented override function, applicable direction and achieved displacement evidence
Run the reverse check for the small endpoint. The same 72 L/min corresponds to 1,080 rev/min in the estimate. Compare this point with the permitted shaft and machine speed. The controller’s approved limits belong in the duty and acceptance records.
Record the shift as a sequence of events
Build a common time base for the signals the approved procedure permits you to record. Start with the requested range, the actual input at the motor regulator and measured shaft speed. Where needed add the two working-port pressures, inlet flow, control supply and an approved indication of regulator position. Use synchronized data or document timing uncertainty between instruments. Separate recordings with no common clock may show apparent delays that belong to the instruments.
Event on the trace
What to mark
What the timestamp can support
Operator or controller requests a shift
Input event at the source
Establishes the request time
Input reaches the regulator
Electrical or pilot signal at the designated check point
Separates command-path delay from the motor's response
Displacement starts to move
Approved position indication or qualified evidence from the test method
Locates the beginning of the hydraulic response
Shaft speed changes
Speed, direction, inlet flow and pressure context
Shows the machine effect and helps identify competing causes
State settles
Final speed, working pressures, load and displacement evidence
Supports comparison with the approved endpoint
Pressure or speed exceeds an agreed limit
Value, duration and procedure response
Identifies an acceptance issue for the machine designer
The time between the first and last entries is a system response. It includes command transmission, hydraulic control, mechanical motion and feedback as applicable. A supplier's component response measured on another rig may be relevant to that component only. For a repeatable machine check, agree on start and end definitions before collecting the trace. “The motor shifted in one second” needs the two events that define that second.
Suppose the display icon changes as the shaft slows, and the test file has no pilot, flow or position channel. Record the two observations and leave the cause open. The next check needs evidence from the regulator input and hydraulic supply.
Separate direct position evidence from a speed-based estimate
Use a documented position signal where the build provides one. A steady flow-speed estimate uses V = 1,000 × Q × ηv / n. Put the result in an estimate column, with the assumed ηv alongside.
At 72 L/min and 720 rev/min, ηv of 0.90 gives 90 cm³/rev. At ηv of 0.85, the same inputs give 85 cm³/rev. The entire difference comes from efficiency. Reserve this calculation for a settled point with a defined flow boundary. During a shift, changing flow, leakage and acceleration complicate the inference.
Also verify which flow the meter covers. A pump outlet meter upstream of branches or charge and auxiliary paths may include oil that does not enter the motor. Entering that whole value can overestimate the effective displacement. The corresponding speed must come from the motor shaft or a properly converted drive measurement. If the ratio or signal scaling is in doubt, retain the raw reading and identify the conversion gap.
Do not infer a guaranteed minimum or maximum setting from a single approximate estimate. Confirm the selected adjustment, setting tolerance and method with the applicable manufacturer information. For a purchase comparison, a documented configured endpoint is the starting requirement. The observed operating point then checks how that configuration behaves in its circuit.
Review the shift in both load directions
A pressure override may respond to a designated port, to the higher of two ports or to other conditions defined by the exact control and optional features. The active port can change when rotation or power transfer reverses. Record which direction and load state were used when checking the override. A result from a forward pull does not settle the expected behavior during reverse operation or braking.
Where the circuit includes a brake, add the release signal and actual brake state to the trace. Obtain the approved engagement and loss-of-power behavior from the machine design. The selector’s default displacement answers only one part of that sequence.
For a proposed replacement, have engineering compare the original and offered control symbols alongside shaft and port drawings. Record both power directions and any pressure-related functions essential to the machine. A code with a similar displacement range can have a different control inlet, signal polarity, port arrangement or override logic. Approval requires the function to match the actual machine requirements.
Use a fault record that can distinguish the causes
Start with the trace and the known duty state. At a warm loaded point, an increased differential and a move toward larger displacement may be the documented pressure response. At a similar speed drop with no achieved shift and lower inlet flow, the pump or the supply path becomes a separate candidate for review. If both flow and displacement changed, the time order and control input determine which measurements are needed next.
Recorded observation
Open question to resolve
Switch command changes and regulator input stays unchanged
Is the command reaching the control through the specified electrical or pilot path?
Correct input arrives and the documented control supply is absent
What part of the approved hydraulic supply path is missing its required condition?
Input holds while pressure reaches a documented override state
Does the control drawing predict the observed move toward larger displacement?
Speed rises without corresponding flow change
Is the motor in a smaller displacement state, or has the speed signal or load changed?
Speed falls while motor inlet flow falls
Which pump, branch or pressure condition changed, and what happened to achieved displacement?
State changes only when the oil is warm
Are operating conditions, supply and load comparable, and what does the manufacturer permit?
Save the settings and original trace before any authorized correction. Use the equipment procedure for control and supply measurements. Assign adjustment, disassembly and pressure release to qualified personnel.
Put the controls into the purchasing specification
Write the inquiry around the shift, including the selected endpoints, working pressure and flow at each duty point, expected direction of change for each input, and the machine's documented default and override needs. Give the supplier the old complete code and circuit excerpt for a replacement. For a new application, give the signed-off load and speed envelope with any constraints on braking and acceleration.
Ask the supplier to identify the offered motor, regulator and configured settings in the reply. Agree on what evidence will confirm the function. Tie the acceptance scope to the control schematic, endpoint settings and signal conditions. State which checks require a witnessed test and which can be confirmed from the build record.
Purchase field
Minimum useful reply
Model and control identity
Complete build and regulator code linked to applicable documentation
Two endpoint settings
Values, tolerances where specified and approved means of verification
Command direction
Input and achieved state mapping with required supply conditions
Override and failure response
Applicable functions and conditions for engineering review
Operating envelope
Speed, torque and pressure conditions in each required state
Interface match
Mounting, shaft, working and case ports, connectors and installation constraints
Acceptance record
Agreed test scope, measurement points, operating conditions and open items
When you send BLINCE an application inquiry, include the model if known, both working points and the control requirements. Request documentation for the selected build before using the example calculations to release an order.
Questions that come up before acceptance
Does a two-position regulator guarantee exactly two shaft speeds?
It selects two displacement states under the specified control conditions. Shaft speed also depends on inlet flow and operating efficiency. The same state can give different speeds at different flows, and the shift can be modified by other documented controls. Specify speed with its duty point rather than treating the displacement labels as fixed rpm settings.
Why can the motor slow even though the fast command stays active?
Check the supplied flow, actual control input and applicable override logic. In a configuration with a pressure-related move toward larger displacement, the motor can slow at the same flow while the request remains unchanged. A drop in flow can produce a similar observation. Tie the pressure, flow and position evidence to the same event before assigning the cause.
Can both endpoints be selected from one published maximum torque?
Use the applicable displacement and working-port differential at each duty. The usable torque also depends on the design, efficiency and limits attached to the required speed and service condition. Keep the continuous duty and any brief loaded event on separate rows, with the relevant evidence for each one.
What should appear on the final test report?
Give the report a build identifier, two endpoints, the test conditions and a drawing of the measurement locations. Attach the time-aligned request, input and response. For each acceptance state, cite the observation or build document that supports the result and name the unresolved requirement.
This article is a general engineering guide. Final component selection should be based on machine drawings, measured hydraulic data, working conditions, safety requirements, and confirmation from a qualified hydraulic engineer or supplier.
Blince Hydraulic Team
Blince Hydraulic is an industry-leading company dedicated to precision-engineered fluid power manufacturing and custom hydraulic solutions. Backed by decades of deep field expertise in industrial machinery and thousands of successful global deployments, our engineering team focuses entirely on high-performance hydraulic component manufacturing, including specialized orbital motors, high-pressure travel drives motor, and robust directional control valves. Our production infrastructure utilizes state-of-the-art multi-axis CNC machining systems and is fully ISO 9001 certified to guarantee repeatable volumetric accuracy across every single manufacturing run.
We deliver fast, highly dependable, and cost-efficient hydraulic solutions to heavy industry distributors, machinery OEMs, and maintenance crews across more than 150 countries. Whether your active project calls for a small-volume batch of customized shaft profiles or a large-scale production run of severe-duty cast iron gear pump, we configure our flexible production schedules to meet your target lead times with total pricing predictability. Partnering with Blince means securing maximum system efficiency, elite material quality, and uncompromised fluid power professionalism.
To learn more about our complete product lineup, visit our official website: www.blince.com.
