NP-112

Hydraulic power generation by the NP-112 pump

The main function of the NP-112 is to generate high-pressure hydraulic flow for a closed-loop hydrostatic drive. The pump changes output flow by altering the angle of the swash plate. When the swash plate angle changes, pump displacement changes, and the direction or amount of hydraulic flow in the closed circuit changes accordingly. This makes the NP-112 suitable for machines where speed, direction and drive force need to be controlled smoothly under variable load.

NP-112 with MP-112 hydraulic motor

The NP-112 normally works in pair with the MP-112 hydraulic motor. Together they form the GST-112 hydrostatic transmission. In this arrangement, the pump supplies high-pressure fluid to the motor, and the motor converts hydraulic energy back into mechanical rotation. Since the system works in a closed circuit, the condition of both units matters. Poor performance may be caused by the pump, the motor, charge circuit, control module, leakage, contaminated fluid, incorrect rotation direction or wear in the high-pressure loop.

Control systems for the NP-112 pump

The NP-112 may be equipped with different control modules depending on the machine and transmission configuration. Common control versions include MN hydromechanical proportional control, HD hydraulic proportional control, EP electric proportional control and ER electric three-position control. These modules change the swash plate angle and therefore regulate pump flow. When selecting a replacement pump, the control type is as important as displacement, rotation direction and shaft design. An incorrectly selected control version may fit mechanically but fail to operate properly in the machine.

Operating pressure and performance of NP-112

The NP-112 is designed for high-pressure hydrostatic systems. Its nominal pressure is 42 MPa, with maximum pressure in the high-pressure line up to 45 MPa. The pump has a maximum working displacement of 110.8 cm³ per revolution and can provide high flow at rated speed. Because of these parameters, the NP-112 must be installed in a system with correct filtration, suitable hydraulic fluid, adequate charge pressure and properly set relief / protection devices. Running the pump with contaminated oil or poor inlet conditions can quickly damage the rotating group.

NP-112 application in heavy and special machinery

The NP-112 is widely used in heavy agricultural, construction and special-purpose machinery. Typical applications include combine harvesters such as Don-1500B, Vector, Acros, KZS-9 and KVK-800 Polesie. It is also used in concrete mixer trucks, road rollers, compactors, drilling equipment, seeding complexes and other machines with hydrostatic drive systems. The exact pump version depends on the machine model, transmission layout, shaft type, rotation direction and control module.

NP-112 versions, rotation and analogs

The NP-112 is available in right-hand and left-hand rotation versions. The shaft design also matters; a 23-spline shaft is one of the common configurations. Before replacement, rotation direction, shaft type, control system and mounting layout should be checked against the machine documentation or the old pump nameplate. The pump may be cross-referenced with analogs such as PVH-112, 416.3.112LY2 and NPA-112, but replacement should be confirmed technically rather than by approximate displacement alone.

Supply and inspection of NP-112

For procurement or repair, the full designation NP-112 should be supplemented with rotation direction, control type, shaft version and required condition. The pump may be supplied new, repaired, overhauled or tested serviceable depending on availability. Before installation, it should be checked for shaft condition, flange, control module, ports, case drain, rotation direction, leakage signs and cleanliness. For a high-pressure hydrostatic pump, bench testing is strongly recommended, including flow, pressure, leakage and control response checks.