ISO/TC 131/SC 8/WG 13 - Positive-displacement pumps, motors and integral transmissions - Methods of testing and presenting basic steady state performance

This document establishes procedures for measuring the average steady-state pressure in a hydraulic fluid power conduit. It is applicable to the measurement of average steady-state pressure in closed conduits with inside diameters greater than 3 mm, transmitting hydraulic fluid power with average fluid velocities less than 25 m/s and average steady-state static pressures less than 70 MPa. It is not applicable to sensors which are flush mounted with, or an integral part of, the closed fluid conduit wall. It provides the formulae for estimating the total uncertainty in a given pressure measurement.

This document establishes general principles for the measurement of performance parameters under static or steady-state conditions. This document provides guidance on the sources and magnitudes of uncertainty to be expected in the calibration of and measurements using hydraulic fluid power components. It describes practical requirements for assessing the capability of the measuring system, and hence the level of uncertainty of the measurement system, or for assisting in developing a system which will meet a prescribed level of uncertainty.

This document specifies methods for determining the performance and efficiency of hydraulic fluid power positive displacement pumps, motors and integral transmissions. It applies to components having continuously rotating shafts. This document specifies the requirements for test installations, test procedures under steady-state conditions and the presentation of test results.

ISO 8426:2008 specifies the methods of determining the derived capacity of hydraulic fluid power positive displacement pumps and motors under steady-state conditions and at defined, continuous shaft rotational frequencies. Units can be tested as a positive displacement pump, with mechanical energy applied to the shaft and hydraulic energy obtained at the outlet fluid connection, or as a motor, with hydraulic energy supplied to the inlet fluid connection and mechanical energy obtained at the shaft.

This part of ISO 4392 describes a method of determining the low speed characteristics of positive displacement rotary fluid power motors, of either fixed or variable displacement types. The method involves testing at slow speeds which may generate frequencies having a significant influence upon the steady continuous torque output of the motor and affect the system to which the motor would be connected.

This part of ISO 4392 specifies two test methods for determining the startability of rotary hydraulic motors. It describes two comparable methods of measurement, namely the constant torque method and the constant pressure method. Since the results obtained by these two methods are equivalent, no preference is given to either.

Describes a method of determining the low-speed characteristics of positive-displacement rotary fluid power motors under constand flow and constant torque conditions. The method involves testing at slow speeds, which may generate frequencies having a significant influence upon the steady continuous torque output of the motor and affect the system to which the motor would be connected. The accuracy of measurement is divided into three classes, A, B and C, which are explained in annex A.