power up / power down hydraulic pump wiring free sample

a)  Press the up button on the hand held remote pendant, to run the trailer bed up 1/3 of the way up. While running the bed up view the hydraulic fluid through the breather cap opening, you may see the fluid returning into the tank. If you see any air pockets or aera- tion of the fluid, please stop and allow the fluid to settle and continue to raise 1/3 of the way up.

a)  While running the bed up view the hydraulic fluid through the breather cap opening, you may see the fluid returning into the tank. If you see any air pockets or aeration of the flu- id, please stop and allow the fluid to settle and continue to raise 2/3 of the way up.

a)  While running the bed up view the hydraulic fluid through the breather cap opening, you may see the fluid returning into the tank. If you see any air pockets or aeration of the flu- id, please stop and allow the fluid to settle, and then continue to raise the bed to the end of the stroke.

Bucher power up/gravity down pump with 6 qt poly tank. Port size is 3/8" NPT.  Reservoir is 6.7" x 6.7" x 13". 1.25 gpm at 1,750 psi. Horizontal mount. Direct replacement for Light, Medium, and Heavy Duty dump kits.

This unit is for power up/hold/gravity down applications. In one direction the manual handle starts unit to power up. In the other direction, the manual handle provides gravity down. In the neutral position, the unit holds steady. The unit features an adjustable relief valve, cartridge hold & lower valves, allowing for easy field service and interchangeability. A pressure compensated flow control for lower function is optional.

In aviation, a power transfer unit (PTU) is a device that transfers hydraulic power from one of an aircraft"s hydraulic systems to another in the event that second system has failed or been turned off.

The PTU is used when, for example, there is right hydraulic system pressure but no left hydraulic system pressure. In this example, the PTU transfers hydraulic power from the right hydraulic system to the left hydraulic system. A PTU consists of a hydraulic motor paired with a hydraulic pump via a shaft.

Large transport category aircraft with hydraulically powered flight controls and utilities typically have multiple, independent hydraulic systems powered by a combination of engine-driven and electrically driven hydraulic pumps. Multiple hydraulic systems are typically needed for redundancy, where for instance if one system fails or loses hydraulic fluid, a surviving system may still provide sufficient power for critical systems to continue safe flight and landing.

On airliners or business jets with powered flight controls, it is typical to have at least two hydraulic power control units (actuators) for each critical flight control surface — these are the elevators, rudder and ailerons. Only two sources might be used if some form of mechanical reversion is present (i.e. the pilot can still fly the aeroplane manually, but with some difficulty, via mechanical linkages and cables if hydraulic power is lost).

On fly-by-wire aircraft, at least three independent power sources are needed. Spoilers and flaps meanwhile are considered secondary flight controls, and may only have a single hydraulic power source, providing the flight control can be deployed symmetrically.

Likewise, landing gear, brakes and nosewheel steering are systems which are not considered critical for flight, and subsequently they are typically only powered by a single hydraulic system on an airliner or business jet.

Where an aircraft utility is powered by a single hydraulic system, PTUs become beneficial in allowing a single source of power, e.g. a pump powered by one surviving engine, to power more than one hydraulic system if the source of power in that system has failed. PTUs only work on the proviso that the system has not punctured and lost its fluid, because they do not permit fluid transfer, only the transfer of mechanical work.

For example, on the original design of the Airbus A320, the landing gear hydraulics (extension/retraction, brakes and steering) were solely powered from the Green (left hand) system, powered by the left-hand engine driven pump. In the event of a port engine failure during take-off, the landing gear would not be able to retract as there is no auxiliary motorpump in the green hydraulic system on an A320. (Modern A320s have the nose wheel steering powered by the yellow system.)

The PTU solves this problem by allowing a rotary mechanical coupling between both systems, so the engine driven pump for the Yellow (right hand) system on the starboard engine, which is oversized for normal hydraulic demand, can dump the excess power into the green system via the PTU, and allow powered landing gear retraction to continue, while maintaining hydraulic pressure to the green system flight controls as well.

Assuring landing gear retraction in a failure case is one potential assurance provided by a PTU. Alternatively, the designer may elect to have a second electric motorpump perform this role if a PTU is not desired. An additional motorpump may be heavier than a PTU however, and complex trade studies may favour one option or the other, depending which failure cases you consider and how important weight is in the trade-off.

On the Airbus A320 the Yellow system may power the Green system, but because it is also bi-directional, if the starboard engine fails, the Green system can help to power the yellow system by dumping excess power into it via the same mechanism. This is also known as a "reversible" PTU.

On some other aircraft the directional of rotation of the PTU, and thereby the fluid flow through it, may be designed to work in only one direction. The Citation X business jet is one such aircraft with a uni-directional PTU protected by check-vales and a back-pressure stall line, designed to allow the right hand hydraulic system to assist the left hand hydraulic system and left hand auxiliary motorpump to retract the landing gear during a Port engine failure only.

On yet other aircraft, the function of a bi-directional reversible PTU can be accomplished with two uni-directional PTUs installed side-by-side arranged in opposite orientations to each other. The hydraulic system of the CH-47 Chinook helicopter uses twin uni-directional PTUs in this fashion.

Hydraulic power transfer units are essentially nothing more than a hydraulic motor coupled to a hydraulic pump via a shaft, as such conceptually they can be any kind of motor or pump such as vane, gear, impeller or in-line piston types, or variable displacement in-line piston types.

A straight-axis in-line piston pump/motor relies on a canted internal swashplate to drive the piston shoes up and down around the internal piston slipway of the pump, lubricated by the fluid itself — this kind of PTU may appear to resemble two cylinders bolted together, with an inlet and outlet port at either end. An example of a straight axis in-line PTU can be found in the Cessna Citation X hydraulic system.

A bent axis in-line piston pump works the same way, but forgoes the canted swashplate, instead the whole rotating group is tilted to achieve the piston displacement.

In yet further representations, a bent axis fixed-displacement motor/pump can be mated with a straight axis variable displacement motorpump, as in the case of the Airbus A320 PTU.

The mechanism by which a PTU works is by surging, PTUs self-start by pure mechanical influence alone resulting from the delta-pressure between the two hydraulic systems it is connected to. Consequently, a PTU accelerates very rapidly under the delta-P induced load, and then stops just as suddenly once the pressure equalizes. Each pressure surge may only be a second long, causing a stop-start mode of operation.

Passengers who have flown on the Airbus A320 will frequently hear the PTU "barking dog", generally when only one engine is running, or when the Yellow system electric motorpump is the only active hydraulic power source, the PTU is mechanically activated. Consequently, normally the PTU is only heard on start-up or shut down. Very rarely is it heard in flight unless a momentary power deficit is present when retracting the gear, or a hydraulic fault has occurred.

In Airbus literature, it is stated that the PTU "self-tests", on startup, however the PTU does not contain any electronic motor assistance and cannot be commanded to start, it starts by itself only when hydraulic pressure is present. However, solenoid energized shut-off valves can isolate the PTU via a push-button switch (pb/sw) in the cockpit, but this feature is rarely used.

KTI is a leader in Hydraulic Power Unit Manufacturing. They are well known for their Top Quality Construction and Building Units that have Low Noise Emissions.

All KTI hydraulics power units are 100% fully inspected to stringent test specifications. The tests ensure our customers they will receive a reliable, high-quality dump trailer power unit that will perform to our design specifications. KTI hydraulic pumps include a 2-year warranty.

Aeration - The presence of dispersed air bubbles in the system"s hydraulic fluid. Aeration can result in severe erosion of pump components when the bubbles collapse as they suddenly encounter high pressure when entering the discharge area of the pump.

Case drain - An external port used to drain off the small amount of oil that collects in the seal and bearing pockets of a hydraulic motor or pump. This oil has slipped through clearances between the gear sides and the housing. If the oil is not drained, the pressure inside the housing would blow out the shaft seal. This becomes a problem only when two or more hydraulic motors are connected in a series.

Cavitation - A phenomenon which occurs when the pressure at a point in a hydraulic system is lowered below the vapor pressure of the oil in the system. This allows bubbles of oil vapor to form in the oil. If this occurs at the pump inlet, the quick pressure rise inside the pump forces these bubbles to collapse violently. This can cause erosion of metal parts, noise and vibration.

Closed Center System - A hydraulic system in which the control valves are closed during neutral, stopping oil flow. Flow in this system is varied, but pressure remains constant.

Closed loop circuit - Once the fluid has been circulated, much like an open loop system, the oil is recirculated at low pressure back to the pump inlet, rather than being returned to the reservoir. This type circuit is more adaptable to hydraulic motor applications.

Cushion Valve - Cushion Valves (or crossover relief valve). These valves absorb pressure spikes caused if a motor or cylinder is brought to an abrupt stop while moving a heavy load. Both the inlet line and the outlet line are connected to each other inside the valve body by two relief valves, each facing opposite the other. If a spike occurs, the valve can discharge the flow to the opposite line. There are four ports on the cushion valve - two are connected to the cylinder or motor, and two are connected to the control valve, and slows down the piston.

Cylinder - A device for converting fluid power into linear or circular motion. Referred to as an "actuator". Customers also refer to these as "pistons" "rams" and "pushrods."

Dead head - A situation that occurs when pressure within a system is stopped or blocked with no place to relief. Pump flow continues to build pressure until something gives way within the system, and thus resulting in damage.

Displacement - The volume of oil displaced by one complete stroke or revolution (of a pump, motor, or cylinder). Usually expressed as CIR (cubic inches per revolution). For example, if a motor rated is at 2.2 CIR, this indicates that for every revolution, the motor displaces or expels 2.2 cubic inches of fluid.

Double-Acting Cylinder - A cylinder in which fluid power can be exerted on both sides of the piston. Sometimes referred to as "power up, power down". This cylinder can be controlled in both the extend and retract phases.

Double pump - Two pumps in one housing. Two separate inlets and outlets are utilized. One shaft drives both pumps. There is a pump at the shaft end and one at the cover end.

Eccentric - Uses a locking ring that fits onto the outside of the bearing, when the ring is rotated up to 180 degrees, the shaft is secured to the bearing. The letters HC indicate eccentric collar.

Force - A push or pull acting upon a body. In a hydraulic cylinder, it is the product of the pressure on the fluid, multiplied by the effective area of the cylinder piston. It is measured in pounds or tons.

Four-Way, Four Position - This valve is identical to four-way, three-position with the fourth position as "float" or "motor" position. Power up, gravity down.

Four-Way, Three-Position - Controls double-acting cylinders. Four-way denotes the flow pattern: (1) inlet, (2) "A" work port, (3) "B" work port, and (4) outlet. Three-position denotes the handle position: (1) forward or up, (2) neutral or middle, and (3) back or down. Power up, gravity down.

Gear Pump - Uses two gears. The "drive" gear is keyed to the shaft and meshes with the "driven" gear. The oil flows around the outside diameter of each gear as they revolve. A suction is formed on the inlet side by the oil being carried away in the cavities formed beneath the teeth of the gears. The oil is then transported around and discharged into the cavity of the outlet port. The meshing of the teeth in the middle seals the inlet from the outlet. These are fixed displacement pumps. The output flow can be varied by changing drive speed.

Gerole - This type of hydraulic motor also has two elements. As the inner gear rotates, rollers which form the displacement chambers provide support by a rolling action which minimizes friction. As with the gerotor type motor, the inner gear has one less tooth than the outer element formed by the rollers.

Hydraulic Amplifier / Intensifier - A hydraulic intensifier is a hydraulic machine for transforming hydraulic power at low pressure into a reduced volume at higher pressure

Lock Valves - These valves are designed to lock a cylinder, or part of a circuit, without leakage while a control valve is in a neutral position. Essentially, these are pilot-operated check valves, allowing flow to an actuator and blocking reverse flow until pilot pressure is applied to "unlock" the circuit. Lock valves can be used for safety devices. They prevent movement of the load if the control valve is accidentally operated (while the pressure source is inactive) and if a line rupture occurs. They are designed for applications where leakage through the control valve could adversely affect the performance of the system such as clamps, outriggers, and work platforms. Both lines to the cylinder from the control valve must be connected to the lock valve, in this way pilot pressure from both the extend side and the retract side of the cylinder can be detected. If pressure drops on one side, the valve "locks" until the pressure is equalized on both sides.

Motor (Hydraulic)- A device for converting fluid energy into mechanical force and motion - usually rotary motion. Basic design types include gear, vane, and piston units.

Motor Spool - Similar to the float spool but intended to allow a hydraulic motor to freewheel. Also prevents "dead stop" in a hydraulic motor by allowing gradual slow down when the valve is moved to neutral.

Open Center System - A hydraulic system in which the control valves are open to continuous oil flow, even in neutral. Pressure in this system is varied, but flow remains constant.

Open loop circuit - A system where the oil is drawn from a reservoir at atmospheric pressure, circulated by a pump under pressure, through valves, into an actuator and then returned to the reservoir at near atmospheric pressure. Most hydraulic systems are of this design.

Piston - A cylindrical part which moves or reciprocates in a cylinder and transmits or receives motion to do work. The disc-shaped element within a cylinder connected to the rod. The surface area of the piston dictates the cylinder’s force capabilities. The hydraulic fluid acts on the surface of the piston opposite the rod. Seals are used on the piston to prevent leakage.

Proportional Flow Dividers - These valves will divide the flow of one pump into two equal flows regardless of variations in load. Most of these valves are 50/50 ratio; however, other ratios can be ordered from the manufacturer.

Pressure Compensated Flow Control Valves - These valves are designed to control the speed of hydraulic cylinders or motors, eliminating the variations in speed caused by changes in load. These valves have an inlet and a "controlled flow" (CF) port as well as an "excess flow" (EF) port. Adjustable flow control valves allow the operator to adjust the flow of the "CF" by varying the size of the orifice of that port. Once the "CF" is set, it will remain nearly constant with variations in pressure on either the "CF" or the "EF" port. Any remaining flow is bypassed to the excess flow port which can be used to supply another circuit or can be directed to tank.

Pressure Relief Valve - These are "safety valves". They serve to set a limit to the rise in pressure in a line or circuit. There are two categories; direct-acting and pilot-operated relief valves. The direct-acting is one in which the poppet is half closed by direct force of a mechanical spring. Any increase in pressure past the "cracking pressure" will cause the poppet to be unseated and allow a small part of the oil to escape. Advantages of the direct-acting relief valve are that they are less expensive than the pilot-operated type and they have a faster response time. Pilot-operated reliefs hold the poppet on its seat by adjustable pilot pressure. The pilot pressure can be supplied internally or externally and is most often from the pump line. When the pump line pressure rises higher than the adjustment set on the relief, the poppet becomes unseated and oil is directed back to tank. When pump line pressure drops below the control setting, the poppet can re-seat and close the valve. The pilot-operated reliefs can be more accurately adjusted and are used more often as the main relief in hydraulic systems.

PTO Pump - This pump is operated by the power take-off shaft of a tractor or other piece of equipment. As opposed to the standard gear pump, which has a shaft of its own that couples to drive a motor or engine.

Regenerative Circuit - A circuit in which pressure fluid discharged from a component is returned to the system to reduce flow input requirements. Often used to speed up the action of a cylinder by directing discharged oil from the rod end to the piston end.

Regulator - Hydraulic regulators maintain the output pressure of a hydraulic system at a set value, minimizing fluctuations in a pressurized line. A hydraulic regulator is typically made of steel, coated steel, or stainless steel and comes with a variety of connections. Hydraulic regulators are designed to hold a tight seal even as the pressure in the line rises. Hydraulic regulators may be used in land-based applications or may be specially designed to work underwater.

Rephasing Cylinder - Rephasing cylinders are two or more cylinders plumbed in series or parallel, with the bores and rods sized such that all rods extend and/or retract equally when flow is directed to the first, or last, cylinder within the system.

Selector Valve - A valve which selects one of two or more circuits in which to direct oil, usually operated manually. The single selector valve permits the flow of one pump to be diverted to one of two hydraulic lines. The double selector valve permits the flow of one pump to be diverted to two separate circuits. The double selector valve has one inlet and one outlet and two sets of work ports, which allow one four-way valve to control two double-acting cylinders. The single selector can control two single-acting cylinders.

Series Circuit - The entire flow of hydraulic oil is available to each work section in sequence from inlet to outlet port. As oil is directed from the inlet port to the work port of the first spool which is shifted, the returning oil to that section is directed back to the open center passage and not the tank port as in parallel valve circuit. The returning oil is then available for any downstream section.

Single-Acting Cylinder - A cylinder will have the capacity to be utilized in only one direction. Commonly referred to as "power up, gravity down". The extend or push phase is controlled by a valve, but the retract or return phase is achieved by the weight of the application. A dump body is a prime example.

Stroke Controls - These controls are used to limit the stroke of a hydraulic cylinder. There are several variations of this idea. Stroke control segments can be added to the rod to limit the return stroke. Some stroke limiters are installed inside the cylinder tube to control the extension or the outward stroke.

Tang - A single protrusion from the base plate and/or the rod of a cylinder, drilled and centered to allow for mounting on an application. This male end fits inside a clevis-type mounting and is pinned.

Three-Way, Three-Position - Controls single-acting cylinders. Three-way denotes the flow pattern. Oil flows through three individual ports: (1) inlet, (2) "A" work port, and (3) "B" work port. Three-position denotes the handle position: (1) forward or up, (2) neutral or middle, and (3) back or down. Power up, gravity down.

Tie Rod Cylinder - A hydraulic cylinder held together by 4 tie bolts that hold the rod end gland and the base plate onto the cylinder tube. The advantage of the tie-rod cylinder is that they are easier to repair in the field and are less expensive.

Torque - The turning effort of a hydraulic motor or rotary cylinder. Usually given in inch-pounds (in-Ibs) or foot-pounds (ft-lbs). The twisting motion produced on the shaft of a motor which provides it the capacity to do work.

Two-stage Pump - Two pump sections contained in one housing, one with a large gear set and one with a small gear set. Both sections utilize a common inlet and outlet. A high-volume flow, at low pressure, is provided as the gear sets work together, resulting in a fast-forward movement of a hydraulic cylinder. An internal sequence valve isolates the small gear set when a preset pressure is reached. This enables the small gear to set to generate several times greater operating pressure. But, because the discharge flow is correspondingly less, the increase in force doesn’t require any more engine horsepower. First stage: low-pressure, high-volume flow. Second stage: high-pressure, low-volume flow.

U-Cup - This is a very common seal that is usually made from rubber or urethane. They are commonly used for dynamic sealing for either a piston or rod seal.

Vane Pump - A pump having multiple radial vanes within a supporting rotor. The rotor is keyed to the shaft and is offset in relation to the cam ring. As the rotor turns, the vanes extend and retract depending on the point of contact with the cam ring. Oil is trapped between the vanes during one-half of the evolution on the inlet side, and the expelled during the other half of the revolution on the outlet side. The vanes extend and retract by either a spring or centrifugal force. These can be variable diplacement pumps.

Welded Cylinder - A hydraulic cylinder which has its base end welded into place. The gland is usually held in place by a retainer ring or snap ring. These cylinders are usually rated for higher pressures.

- either it is the static lift from one height to an other or the total head loss component of the system - and can be calculated like Ph(kW) = q ρ g h / (3.6 106)

600 gpm of water is pumped a head of 110 ft. The efficiency ofthe pump i s 60% (0.6) and the specific gravity of water is 1. The pump shaft power can be calculated as

The shaft power - the power required transferred from the motor to the shaft of the pump - depends on the efficiency of the pump and can be calculated as Ps(kW) = Ph(kW)/ η (3)