How to Match Hydraulic Pump and Motor?

Matching a hydraulic pump and motor means making sure the pump can provide the flow, pressure, and power required by the motor under real operating conditions. The two components do not need the same displacement, speed, or physical size. Instead, they must work together so the hydraulic motor reaches the required rpm and torque without pushing either component beyond its continuous operating limits.

The basic relationship is straightforward. The hydraulic pump determines how much oil enters the circuit, while the hydraulic motor converts that oil flow and pressure difference into shaft rotation. Flow primarily influences motor speed. Pressure difference primarily influences motor torque. Pump displacement and pump drive speed determine how much flow is available, while motor displacement determines how much oil is required for each motor revolution.

A properly matched hydraulic pump motor system also needs sufficient input power, suitable pressure ratings, compatible control methods, acceptable efficiency, correct circuit architecture, and adequate cooling. Simply connecting a high-flow hydraulic pump to a high-speed hydraulic motor does not guarantee good performance.

Xiamen Senhengyuan Machinery Equipment Co., Ltd. supplies hydraulic pumps and motors in fixed and variable displacement configurations for mobile and industrial hydraulic systems. The following matching process provides a practical framework for selecting components that can operate together effectively.

What Does Matching a Hydraulic Pump and Motor Mean?

Pump-and-motor matching means balancing four primary quantities:

• Pump flow

• System pressure

• Motor displacement

• Required motor speed and torque

The pump must provide enough flow for the motor to reach the desired rpm. The hydraulic circuit must also provide enough pressure difference across the motor for it to develop the required torque.

At the same time, the pump cannot demand more mechanical input power than the electric motor or engine can supply. The hydraulic motor cannot be operated above its maximum speed, pressure, case-pressure, or shaft-load ratings.

A good match therefore satisfies the complete operating point rather than only one parameter.

Start With the Machine, Not the Hydraulic Pump

The correct matching process begins at the driven machine.

Before selecting a hydraulic pump or motor, determine how fast the load must rotate and how much torque it requires. A conveyor, wheel drive, winch, mixer, drilling head, fan, and travel mechanism can all require very different torque-speed characteristics.

The key starting values are:

These values define what the hydraulic motor must deliver. The pump is then selected to support that motor.

Choosing the pump first can force the rest of the system around an arbitrary flow rate and often leads to poor efficiency or unnecessary component oversizing.

Match Pump Flow to Hydraulic Motor Speed

Motor speed is closely related to oil flow.

A useful preliminary formula is:

Motor Speed (rpm) ≈ Pump Flow (L/min) × 1000 × Motor Volumetric Efficiency ÷ Motor Displacement (cc/rev)

If the required motor speed is known:

Required Motor Flow (L/min) ≈ Motor Speed × Motor Displacement ÷ (1000 × Volumetric Efficiency)

Suppose an 80 cc/rev hydraulic motor needs to operate at 900 rpm. If its volumetric efficiency is estimated at 92%:

Required Flow ≈ 900 × 80 ÷ (1000 × 0.92)

≈ 78.3 L/min

The pump must therefore be capable of supplying approximately 78 L/min at that operating condition, plus any additional flow needed elsewhere in the circuit.

This immediately shows why pump displacement and motor displacement do not need to match.

Match Pressure to Hydraulic Motor Torque

Flow makes the motor rotate, but pressure difference allows it to produce torque.

A practical preliminary torque relationship is:

Motor Torque (N·m) ≈ Pressure Difference (bar) × Motor Displacement (cc/rev) × Mechanical Efficiency ÷ 62.8

If torque is known, the pressure requirement can be estimated as:

Pressure Difference ≈ Torque × 62.8 ÷ (Motor Displacement × Mechanical Efficiency)

Suppose the 80 cc/rev motor must deliver 250 N·m and estimated mechanical efficiency is 90%.

The required pressure difference is approximately:

250 × 62.8 ÷ (80 × 0.90)

≈ 218 bar

The hydraulic pump and circuit therefore need to provide sufficient pressure for the motor to operate around this load point.

However, the pump does not continuously “create” a fixed pressure simply because it has a 250-bar or 350-bar rating. The load creates resistance to flow, and system pressure rises as required to overcome that resistance until limited by the pressure-control system.

Flow and Pressure Must Be Matched Together

One of the most common hydraulic design errors is looking at flow and pressure separately.

A pump may provide sufficient flow to achieve the required motor rpm but still be unable to support the pressure needed for the load.

Alternatively, the pump may have a high pressure rating but insufficient flow, causing the motor to produce adequate torque at very low speed while failing to meet the required production rate.

Consider this example:

The pump therefore needs to support roughly 78 L/min at a working pressure around 218 bar, plus system pressure losses and appropriate design margin.

This operating point is much more useful than requesting only “an 80 L/min hydraulic pump.”

How to Match Pump Displacement to Motor Requirements

Once required motor flow is known, calculate the pump displacement.

The basic pump-flow relationship is:

Pump Flow (L/min) ≈ Pump Displacement (cc/rev) × Pump Speed (rpm) × Pump Volumetric Efficiency ÷ 1000

Rearranged:

Pump Displacement ≈ Required Flow × 1000 ÷ (Pump Speed × Pump Volumetric Efficiency)

Using the previous requirement of approximately 78.3 L/min, assume the pump runs at 1,500 rpm with 93% volumetric efficiency:

Pump Displacement ≈ 78.3 × 1000 ÷ (1500 × 0.93)

≈ 56.1 cc/rev

A pump with a displacement near this value would therefore be a reasonable starting point.

A variable unit such as the A7VO axial piston variable hydraulic pump can be considered where the system needs changing flow or operating conditions rather than one fixed delivery rate.

Does the Pump Need the Same Displacement as the Motor?

No.

A hydraulic pump and motor can have completely different displacements and still form a properly matched transmission.

For example:

• Pump displacement: 50 cc/rev

• Pump speed: 1,500 rpm

• Motor displacement: 100 cc/rev

Ignoring losses, the pump theoretically delivers:

50 × 1500 ÷ 1000 = 75 L/min

A 100 cc/rev motor receiving 75 L/min would theoretically turn at:

75 × 1000 ÷ 100 = 750 rpm

The pump therefore rotates twice as fast as the hydraulic motor because the motor requires twice as much oil per revolution.

This is a normal hydraulic transmission relationship.

Fixed Pump and Fixed Motor Matching

A fixed-displacement pump combined with a fixed-displacement motor creates a relatively predictable speed relationship.

If pump speed remains stable, pump flow remains approximately proportional to pump displacement. Since motor displacement is also fixed, motor speed remains closely tied to pump speed.

Ignoring losses:

Motor Speed ≈ Pump Speed × Pump Displacement ÷ Motor Displacement

If:

• Pump speed = 1,500 rpm

• Pump displacement = 40 cc/rev

• Motor displacement = 80 cc/rev

Then theoretical motor speed is approximately:

1500 × 40 ÷ 80 = 750 rpm

Actual speed will be lower because of pump and motor volumetric losses.

A fixed-displacement motor such as the A2FM Axial Piston Fixed Motor is designed for hydrostatic drives in open and closed circuits. Its output speed depends on pump flow and motor displacement, while output torque increases with pressure differential.

Fixed pump-and-motor systems are useful when operating conditions remain relatively stable and complex speed control is unnecessary.

Variable Pump With Fixed Motor

A variable-displacement hydraulic pump combined with a fixed motor provides more flexible speed control.

The motor displacement remains constant, so changing pump displacement changes flow and therefore motor rpm.

For example, reducing pump displacement from 60 cc/rev to 30 cc/rev at the same pump speed approximately halves theoretical flow. If the motor displacement remains unchanged, motor speed also decreases accordingly.

This arrangement is useful for machinery requiring adjustable speed while maintaining a mechanically simple hydraulic motor.

The A10VO/A10VSO hydraulic axial piston variable pump is one example of a variable-displacement piston pump family suitable for systems where hydraulic output needs to follow changing operating demand.

Variable pumps can also reduce wasted energy compared with systems that continuously produce maximum flow and then throttle unwanted flow through valves.

Fixed Pump With Variable Motor

Another option is using a fixed pump with a variable-displacement hydraulic motor.

The pump supplies relatively constant flow, while motor displacement changes.

When motor displacement increases, more oil is required per revolution. Motor speed decreases, but torque available per unit pressure increases.

When displacement decreases, the same flow turns the motor faster, but torque per bar decreases.

The A6VM axial piston variable motor is designed around this operating principle.

This configuration can be useful where equipment needs:

• High torque at low speed

• Higher speed under lighter load

• Stepless speed variation

• Changing drive conditions

• Hydrostatic travel control

Variable Pump With Variable Motor

A variable pump combined with a variable hydraulic motor provides the widest operating range.

Both pump displacement and motor displacement can be adjusted.

At low travel speed or heavy working load, the motor can operate at a larger displacement to provide higher torque.

As load decreases, motor displacement can be reduced to increase speed. The variable pump can simultaneously adjust system flow according to demand.

This architecture is widely suited to advanced hydrostatic transmissions because it provides a broad combination of speed and torque.

However, control complexity also increases.

The system must coordinate:

• Pump displacement

• Motor displacement

• Pressure limitation

• Speed demand

• Load changes

• Charge pressure

• Cooling

• Electronic or hydraulic controls

A poorly coordinated variable pump and motor can operate less efficiently than a correctly matched simpler system.

Match Hydraulic Power, Not Just Flow and Pressure

The pump must also have enough mechanical input power available from the engine or electric motor.

Hydraulic power can be estimated using:

Hydraulic Power (kW) ≈ Pressure (bar) × Flow (L/min) ÷ 600

Using the previous example:

• Pressure = 218 bar

• Flow = 78.3 L/min

Hydraulic power is approximately:

218 × 78.3 ÷ 600 ≈ 28.4 kW

This is hydraulic output power before motor losses.

The pump itself also has efficiency losses. If pump overall efficiency were 90%, the required pump input power would be approximately:

28.4 ÷ 0.90 ≈ 31.6 kW

The engine or electric motor driving the pump must therefore be capable of providing this power under the required operating conditions.

A pump can have enough displacement and pressure rating but still be a poor match if the available prime mover cannot supply the required shaft power.

Match Motor Power to the Mechanical Load

The same power balance should be checked at the hydraulic motor.

Mechanical motor output power can be estimated from:

Mechanical Power (kW) ≈ Torque (N·m) × Speed (rpm) ÷ 9550

Using:

• Torque = 250 N·m

• Speed = 900 rpm

The required mechanical output is approximately:

250 × 900 ÷ 9550 ≈ 23.6 kW

If the hydraulic input is around 28.4 kW, the difference represents losses within the motor and circuit.

This check is useful because independently calculated pressure and flow values should still produce a reasonable power balance.

If the calculations imply 25 kW mechanical output from only 15 kW of hydraulic input, something in the assumptions is wrong.

Pump and Motor Matching Example

Assume a machine requires:

• Motor speed: 900 rpm

• Continuous torque: 250 N·m

• Motor displacement: 80 cc/rev

• Motor volumetric efficiency: 92%

• Motor mechanical efficiency: 90%

• Pump speed: 1,500 rpm

• Pump volumetric efficiency: 93%

The preliminary matching result becomes:

The selected pump and motor should then be checked against actual performance curves, continuous ratings, peak ratings, speed limits, controls, and system losses.

Why Pump Rated Pressure and Motor Rated Pressure Must Be Compatible

The pump's maximum pressure cannot simply be matched to the motor's maximum pressure number.

Continuous ratings matter more during normal operation.

Suppose a pump can briefly reach 350 bar but is intended to operate continuously at a lower pressure. If the motor requires near-maximum system pressure continuously, the pump may overheat or experience reduced life even though it can technically reach that pressure.

The same applies to the hydraulic motor.

A motor may tolerate short pressure peaks above its continuous rating, but those peak values should not be treated as normal operating pressure.

Match:

• Continuous pump pressure

• Continuous motor pressure

• Peak pump pressure

• Peak motor pressure

• Relief-valve setting

• Circuit pressure losses

The system should normally operate comfortably within continuous component ratings.

Match Maximum Pump Flow to Maximum Motor Speed

Overspeed is another important matching risk.

If a hydraulic pump can provide substantially more flow than the motor needs, the motor can exceed its maximum rated rpm.

This is particularly important with a high speed hydraulic motor, where bearings, rotating components, case pressure, inlet conditions, and lubrication become increasingly sensitive at higher speed.

Maximum pump flow should therefore be checked against:

Maximum Motor Speed ≈ Maximum Flow × 1000 × Volumetric Efficiency ÷ Motor Displacement

Flow-control valves or pump-displacement limits may be required if the pump is capable of supplying more oil than the motor can safely accept.

Match Minimum Motor Speed as Well

Maximum speed is not the only consideration.

Some hydraulic motors operate smoothly at very low rpm, while others may experience speed ripple, stick-slip behavior, or reduced efficiency.

A system designed for a wide operating range should therefore check:

• Minimum stable motor speed

• Maximum continuous motor speed

• Intermittent maximum speed

• Starting efficiency

• Low-speed torque

• Control response

A hydraulic motor that performs well at 2,000 rpm may not be the best choice for a machine that frequently operates at 10 rpm under heavy load.

Match the Control Method

Hydraulic components must also use compatible control strategies.

A variable pump may use:

• Pressure control

• Flow control

• Load-sensing control

• Power control

• Electronic proportional control

• Mechanical displacement control

A variable motor may use:

• Hydraulic pressure control

• Mechanical control

• Electronic proportional control

• Two-position displacement control

• Automatic pressure-dependent control

The pump and motor can be hydraulically compatible but still produce poor machine behavior if their control systems do not work together.

For example, a variable pump attempting to reduce flow under light load while a variable motor simultaneously changes displacement can create unexpected speed changes unless the control logic is coordinated.

Open Circuit Pump and Motor Matching

In an open hydraulic circuit, the pump draws oil from a reservoir and sends it through the motor. Return oil then flows back to the reservoir.

Typical matching priorities include:

• Pump suction conditions

• Pump flow capacity

• Motor return pressure

• Reservoir size

• Return filtration

• Cooling

• Directional valve capacity

• Relief-valve setting

Open circuits are common in industrial hydraulic systems where several actuators may share one pump.

If several motors operate simultaneously, pump flow must support their combined demand.

A pump matched correctly to one motor can become undersized if another actuator is activated at the same time.

Closed Circuit Pump and Motor Matching

Closed hydrostatic circuits connect the main pump flow directly to the motor and return motor flow directly to the pump.

These systems are common in travel drives, mobile machinery, winches, and hydrostatic transmissions.

Closed circuits require additional attention to:

• Charge pump flow

• Charge pressure

• Case drains

• Flushing flow

• Cooling

• High-pressure relief valves

• Reversing operation

• Overrunning loads

Variable pump and variable motor combinations are especially useful in closed circuits because they can produce broad transmission ratios without a conventional mechanical gearbox.

The A6VM variable motor, for example, is intended for hydraulic drive applications requiring adjustable displacement and changing speed-torque conditions.

Match Pump Rotation and Motor Direction Requirements

Rotation direction should be confirmed before ordering.

Hydraulic pumps may have defined clockwise, counterclockwise, or reversible shaft-rotation configurations. Motor direction depends on port flow direction and internal design.

A reversible application needs more than simply swapping hoses.

Check:

• Allowed motor rotation directions

• Pump shaft rotation

• Port configuration

• Case-drain connection

• Pressure at return ports

• Overcenter or braking valves

• Reversing pressure spikes

Incorrect rotation or port connection can prevent operation or damage the component.

Match Case Drain Requirements

Many piston pumps and motors require dedicated case-drain lines.

Internal leakage lubricates and cools the rotating group before returning through the case-drain connection.

If the drain line is too small, restricted, connected incorrectly, or exposed to excessive back pressure, case pressure can increase.

Excessive case pressure can damage shaft seals and reduce component life.

Pump and motor matching should therefore include:

• Required drain-line size

• Maximum allowable case pressure

• Drain routing

• Reservoir connection

• Cooler or filter restrictions

• Expected case-drain flow

This becomes particularly important at high speed and high pressure.

Match Hydraulic Oil and Operating Temperature

The pump and motor should be compatible with the same hydraulic fluid and viscosity range.

Oil that is too thick increases mechanical drag, suction losses, and cold-start difficulty.

Oil that is too thin increases internal leakage and can reduce lubrication protection.

Temperature affects both viscosity and component efficiency.

The system should therefore be designed so the pump and motor operate within compatible:

• Fluid types

• Viscosity ranges

• Temperature limits

• Filtration requirements

• Cleanliness targets

Oil condition affects the entire hydraulic pump motor system, not one component in isolation.

Match Filtration to the Most Sensitive Component

A system is only as contamination-tolerant as its most sensitive hydraulic component.

Precision piston pumps and piston motors contain closely fitted moving surfaces. Contamination can increase leakage, scratch valve plates, damage pistons, accelerate bearing wear, and interfere with control mechanisms.

The filter system should therefore be selected according to the cleanliness requirement of the most sensitive pump, motor, or valve.

Consider:

• Suction protection where appropriate

• Pressure filtration where required

• Return filtration

• Offline filtration

• Breather filtration

• Water control

Installing a new hydraulic pump and motor without correcting contaminated oil can quickly damage both replacement components.

Match Cooling Capacity to System Losses

Every hydraulic system converts some input power into heat.

Heat comes from:

• Pump inefficiency

• Motor inefficiency

• Valve throttling

• Pressure drops

• Internal leakage

• Pipe friction

A system operating at 30 kW hydraulic input with 80% overall efficiency can generate several kilowatts of heat continuously.

If the oil cooler and reservoir cannot remove this heat, fluid temperature rises. Higher temperature lowers viscosity, increases leakage, and can further reduce efficiency.

Pump and motor matching should therefore include a thermal check, especially for continuous-duty systems.

Matching a High Speed Hydraulic Motor

A high speed hydraulic motor requires particular attention because high rpm magnifies several hydraulic and mechanical limitations.

The pump must supply enough flow to reach the target rpm, but the motor must remain below its continuous and intermittent maximum speed.

Check:

High speed should never be calculated from flow alone.

What Happens If the Pump Is Too Large?

An oversized hydraulic pump may produce much more flow than the motor requires.

This can cause:

• Motor overspeed

• Excess throttling

• Relief-valve operation

• Higher heat generation

• Larger required valves and hoses

• Higher input power demand

• Increased component cost

A variable pump can reduce some of these disadvantages if displacement is controlled according to demand.

However, using a much larger pump and permanently throttling the excess flow is generally inefficient.

What Happens If the Pump Is Too Small?

An undersized pump cannot provide sufficient flow for the required motor speed.

The motor may still produce torque if sufficient pressure is available, but it will rotate too slowly.

Other symptoms can include:

• Slow cycle times

• Speed reduction when multiple actuators operate

• Poor machine productivity

• Difficulty maintaining rpm under leakage

• Inability to achieve high-speed mode

Increasing pressure will not solve a flow shortage.

This distinction is critical during troubleshooting.

What Happens If the Hydraulic Motor Is Too Small?

A motor with too little displacement may need very high pressure to produce the required torque.

It can also rotate too quickly when connected to the available pump flow.

Possible results include:

• Excessive system pressure

• Motor overspeed

• Poor starting performance

• High mechanical stress

• Frequent relief-valve operation

The motor may appear attractive because of its compact size but still be unsuitable for the required load.

What Happens If the Hydraulic Motor Is Too Large?

An oversized motor generally produces more torque per bar but requires more flow per revolution.

If the existing hydraulic pump cannot provide enough flow, the motor runs too slowly.

A larger motor can also increase:

• Physical size

• Weight

• Cost

• Fluid demand

• Rotary inertia

Oversizing should therefore not be used as a substitute for proper load calculations.

Common Hydraulic Pump and Motor Matching Mistakes

Several matching errors appear repeatedly in hydraulic systems.

A reliable system should be evaluated as one energy-conversion chain rather than as separate catalog components.

Practical Pump and Motor Matching Checklist

Before finalizing the components, confirm the following:

If all of these parameters are compatible, the hydraulic pump and motor are much more likely to work as a stable drivetrain.

Why Choose Xiamen Senhengyuan Machinery Equipment Co., Ltd.?

Xiamen Senhengyuan Machinery Equipment Co., Ltd. supplies hydraulic pumps, hydraulic motors, valves, and related components for mobile and industrial hydraulic systems.

Its product range includes fixed and variable piston pumps as well as fixed and variable hydraulic motors. This allows buyers to compare different combinations according to the required flow, pressure, torque, speed, and control strategy.

For relatively stable duty, a fixed hydraulic motor can provide a straightforward speed-to-flow relationship. Variable motors can support wider speed and torque ranges. Variable hydraulic pumps can adjust flow according to changing system demand and can improve control flexibility.

Product selection should still be based on application data rather than model familiarity.

When requesting a pump and motor match, provide:

• Required motor torque

• Required motor speed

• Pump drive speed

• Available engine or electric motor power

• Continuous pressure

• Peak pressure

• Required flow

• Circuit type

• Direction of rotation

• Duty cycle

• Hydraulic oil

• Operating temperature

• Shaft and flange dimensions

• Port configuration

• Existing component model numbers if replacing equipment

This information allows the pump and motor combination to be evaluated as a complete hydraulic transmission.

Conclusion

Matching a hydraulic pump and motor requires more than choosing components with similar pressure or displacement ratings.

The process starts with the driven machine. Determine the required torque and speed first. Motor displacement can then be selected according to torque, pressure, and speed requirements.

The required motor flow determines the hydraulic pump flow. Pump displacement is then matched to pump drive speed and volumetric efficiency.

Pressure primarily supports motor torque. Flow primarily determines motor speed. Pressure and flow together determine hydraulic power.

The pump's required shaft power must remain within the capacity of the engine or electric motor driving it. Both pump and motor should also remain within their continuous pressure and speed ratings rather than operating continuously at peak values.

Fixed pump and fixed motor systems provide simple operating relationships. Variable pumps and variable motors provide greater control flexibility but require more careful coordination.

Oil viscosity, case drainage, filtration, cooling, line losses, circuit type, and control strategy must also be compatible.

Xiamen Senhengyuan Machinery Equipment Co., Ltd. supplies different hydraulic pump, hydraulic motor, and hydraulic pump motor solutions for industrial and mobile applications.

The practical matching sequence is:

Machine Load → Motor Torque and Speed → Motor Displacement → Required Pressure and Flow → Pump Displacement → Pump Input Power → Control and Circuit Verification

Following this sequence produces a hydraulic drive based on actual machine requirements rather than simply matching catalog numbers.

FAQ

How do I match a hydraulic pump to a hydraulic motor?

Start with the torque and speed required from the motor. Select motor displacement based on torque and available pressure. Calculate the flow needed for the required motor rpm, then select a pump displacement that can provide that flow at the available pump drive speed.

Should pump displacement equal motor displacement?

No. Pump and motor displacement do not need to be equal. Pump displacement determines flow according to pump speed, while motor displacement determines how much oil is required for each motor revolution.

What determines hydraulic motor speed?

Motor speed is mainly determined by hydraulic flow and motor displacement. More flow generally produces higher rpm. Larger motor displacement reduces speed for the same flow.

What determines hydraulic motor torque?

Torque is mainly determined by pressure difference across the motor and motor displacement. Larger displacement or greater pressure difference generally increases available torque.

Can a hydraulic pump have a higher pressure rating than the motor?

Yes, but the circuit must prevent the motor from being exposed to pressure above its allowable rating. Relief valves, pressure controls, and system settings should be matched to the weakest pressure-rated component.

What happens if the hydraulic pump is too large for the motor?

Excessive pump flow can overspeed the motor or force excess oil through flow-control or relief valves. This can increase energy loss, oil temperature, and system cost.

What happens if the hydraulic pump is too small?

The motor will normally run slower than required because insufficient flow is available. Increasing system pressure does not correct a flow shortage.

Can a small hydraulic motor work with a large pump?

It can only work safely if motor speed remains within its rated limit and excess flow is controlled correctly. A large pump can easily overspeed a small-displacement motor.

How do I match a high speed hydraulic motor?

Calculate the flow needed for the target rpm and confirm that pump flow remains within the motor's speed limit. Also check inlet conditions, case pressure, oil viscosity, bearings, cooling, and cavitation risk.

Is a variable hydraulic pump better for a hydraulic motor?

Not always. A variable pump is useful when motor speed or system demand changes frequently. A fixed pump can be simpler and cost-effective where operating conditions remain stable.

Can I use a variable pump with a fixed motor?

Yes. Changing pump displacement changes motor flow and therefore motor speed while motor displacement remains fixed. This is a common way to achieve hydraulic speed control.

Can I use a fixed pump with a variable motor?

Yes. Changing motor displacement changes the relationship between speed and torque while pump flow remains relatively stable. This can provide a wider operating range.

How do I calculate pump flow for a hydraulic motor?

A practical formula is:

Flow (L/min) ≈ Motor Speed × Motor Displacement ÷ (1000 × Motor Volumetric Efficiency)

The final flow requirement should also account for leakage and any other circuit flow demand.

How do I calculate pump displacement?

A practical formula is:

Pump Displacement (cc/rev) ≈ Required Flow × 1000 ÷ (Pump Speed × Pump Volumetric Efficiency)

Use actual manufacturer efficiency and operating data during final selection.

What information should I provide for hydraulic pump and motor matching?

Provide required motor speed, continuous and peak torque, pump drive rpm, available input power, working pressure, peak pressure, required flow, circuit type, duty cycle, shaft and flange dimensions, port configuration, direction, hydraulic fluid, operating temperature, and current component models where applicable.