ISO 18170:2017

Aerospace series — AC induction electric motor driven, variable delivery, hydraulic pumps — General requirements

ISO 18170:2017 establishes the general requirements for electric motor driven, variable delivery, hydraulic pumps suitable for use in aircraft hydraulic systems. ISO 18170:2017 includes the general requirements for Alternating Current (AC) induction electric motor powered units. The AC power electrical power supply can be either controlled to provide a Constant Frequency (CF) or uncontrolled to provide a Variable Frequency (VF) AC supply to the electric motor. ISO 18170:2017 is intended to be used in conjunction with the detail specification that is particular to each application.

Série aérospatiale — Pompes hydrauliques à débit variable, actionnées par des moteurs électriques à induction CA — Exigences générales

General Information

• Status: Published
• Publication Date: 02-May-2017
• ICS: 49.080 - Aerospace fluid systems and components
• Technical Committee: ISO/TC 20/SC 10 - Aerospace fluid systems and components
• Drafting Committee: ISO/TC 20/SC 10/WG 9 - Hydraulic power and actuation equipment
• Current Stage: 9092 - International Standard to be revised
• Start Date: 12-Dec-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 20186-2:2019 - Molecular in vitro diagnostic examinations — Specifications for pre-examination processes for venous whole blood — Part 2: Isolated genomic DNA
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18170
First edition
2017-04
Aerospace series — AC induction
electric motor driven, variable
delivery, hydraulic pumps — General
requirements
Série aérospatiale — Pompes hydrauliques à débit variable,
actionnées par des moteurs électriques à induction CA — Exigences
générales
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 8
4.1 Order of precedence . 8
4.2 Electrical system characteristics . 8
4.3 Hydraulic system characteristics . 8
4.4 Airworthiness requirements. 8
4.5 Qualification . 8
5 Functional requirements . 8
5.1 Functional requirements - electrical . 8
5.1.1 AC power requirements . 8
5.1.2 Electromagnetic interference .10
5.1.3 Electrical bonding .10
5.1.4 Protection requirements .11
5.1.5 Electric motor cooling methods .11
5.2 Functional requirements — Hydraulic .12
5.2.1 Hydraulic fluid .12
5.2.2 EMP pump pressure .12
5.2.3 Inlet pressure .13
5.2.4 Case drain pressures .13
5.2.5 Flows .14
5.2.6 EMP pump characteristics .15
5.2.7 Rated speed .15
5.2.8 Efficiency .17
5.2.9 Heat rejection .18
5.2.10 Variable delivery control .18
5.2.11 Rated temperature .21
5.2.12 Dry running .21
5.3 Functional requirements — EMP integrated assembly .21
5.3.1 Acoustic noise level .21
5.3.2 Endurance .21
5.4 Environmental requirements .21
6 Detailed design requirements .22
6.1 Dimensionally critical components .22
6.2 Maintainability features .22
6.3 Seals .22
6.4 Lubrication .22
6.5 Balance .23
6.6 Self-contained failure .23
6.7 Safety wire sealing .23
6.8 Electro-conductive bonding .23
6.9 Marking .23
6.9.1 Nameplate .23
6.9.2 Fluid identification .24
6.9.3 Ports .24
6.9.4 Direction of rotation .24
6.9.5 Electrical connection details .24
7 Strength requirements .24
7.1 General .24
7.2 Electric motor .24
7.2.1 Motor case .24
7.3 Hydraulic pump requirements .24
7.3.1 Pressure loads .24
7.3.2 Proof pressure .25
7.3.3 Ultimate pressure .25
7.3.4 Pressure impulse (fatigue) .25
7.3.5 Port strength.26
8 Construction .26
8.1 Materials .26
8.1.1 General.26
8.1.2 Metals .26
8.2 Corrosion protection .27
8.2.1 General.27
8.2.2 Ferrous and copper alloys .27
8.2.3 Aluminium alloys .28
8.3 Castings .28
9 Installation requirements.28
9.1 Dimensions .28
9.2 Mass .28
9.2.1 General.28
9.2.2 Centre of mass .28
9.3 Mounting .28
9.4 Orientation .28
9.5 Hydraulic ports .28
9.6 Electrical connections .29
10 Maintenance .29
10.1 Maintenance concept .29
10.2 Service life limitations and storage specifications .29
11 Reliability .29
11.1 Equipment compliance .29
11.2 Requirements .29
12 Quality assurance provisions .29
12.1 Responsibility for inspection .29
12.2 Classification of tests .30
12.3 Test stand requirements .30
12.3.1 General.30
12.3.2 Hydraulic requirements .30
12.3.3 Electrical requirements .30
13 Acceptance tests .31
13.1 General .31
13.2 Examination of the product .31
13.3 Test program .31
13.3.1 General.31
13.3.2 Electrical checks .31
13.3.3 Hydraulic checks .32
13.3.4 Break-in run .32
13.3.5 Proof pressure test .32
13.3.6 Load cycles .32
13.3.7 Tear-down inspection . .33
13.3.8 Run-in .33
13.3.9 Functional tests .33
13.3.10  Pressure control test .34
13.3.11  Calibration .34
13.3.12  Efficiency check .35
13.3.13  Wear test .35
iv © ISO 2017 – All rights reserved

13.3.14  Electro-conductive bonding .36
13.3.15  Storage and packaging .36
14 Qualification tests .36
14.1 Purpose .36
14.2 Qualification procedure .37
14.2.1 Qualification by analogy .37
14.2.2 EMP qualification test report .37
14.2.3 Samples and program of qualification tests .37
14.2.4 Dimensional check .38
14.2.5 Expanded envelope acceptance tests .38
14.2.6 Proof pressure and load cycle tests .38
14.2.7 Calibration .38
14.2.8 Maximum pressure and response time tests .39
14.2.9 Heat rejection test .41
14.2.10 Loss of cooling .41
14.2.11  Electrical tests .42
14.2.12 Endurance test .43
14.2.13  Minimum inlet pressure test .48
14.2.14  Dry run test .48
14.2.15 Environmental tests .48
14.2.16 Structural tests .50
14.2.17  Explosion proof test . . .52
14.2.18  Short circuit test .52
14.2.19  Drive coupling shear test .52
14.2.20  Supplementary tests .53
Bibliography .54
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the WTO principles in
the Technical Barriers to Trade (TBT) see the following URL: www .i so .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles,
Subcommittee SC 10, Aerospace fluid systems and components.
vi © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 18170:2017(E)
Aerospace series — AC induction electric motor
driven, variable delivery, hydraulic pumps — General
requirements
1 Scope
This document establishes the general requirements for electric motor driven, variable delivery,
hydraulic pumps suitable for use in aircraft hydraulic systems.
This document includes the general requirements for Alternating Current (AC) induction electric motor
powered units. The AC power electrical power supply can be either controlled to provide a Constant
Frequency (CF) or uncontrolled to provide a Variable Frequency (VF) AC supply to the electric motor.
This document is intended to be used in conjunction with the detail specification that is particular to
each application.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2093, Electroplated coatings of tin — Specification and test methods
ISO 2669, Environmental tests for aircraft equipment — Steady-state acceleration
ISO 2671, Environmental tests for aircraft equipment — Part 3.4: Acoustic vibration
ISO 3323, Aircraft — Hydraulic components — Marking to indicate fluid for which component is approved
ISO 3601-1:2012, Fluid power systems — O-rings — Part 1: Inside diameters, cross-sections, tolerances and
designation codes
ISO 6771, Aerospace — Fluid systems and components — Pressure and temperature classifications
ISO 7137, Aircraft — Environmental conditions and test procedures for airborne equipment
ISO 7320, Aerospace — Couplings, threaded and sealed, for fluid systems — Dimensions
ISO 8078, Aerospace process — Anodic treatment of aluminium alloys — Sulfuric acid process, undyed coating
ISO 8079, Aerospace process — Anodic treatment of aluminium alloys — Sulfuric acid process, dyed coating
ISO 8081, Aerospace process — Chemical conversion coating for aluminium alloys — General purpose
ISO 8278, Aerospace series — Hydraulic, pressure compensated, variable delivery pumps — General
requirements
ISO 8625-1, Aerospace — Fluid systems — Vocabulary — Part 1: General terms and definitions related to
pressure
ISO 8625-2, Aerospace — Fluid systems — Vocabulary — Part 2: General terms and definitions relating to
flow
ISO 8625-3, Aerospace — Fluid systems — Vocabulary — Part 3: General terms and definitions relating to
temperature
ISO 11218:1993, Aerospace — Cleanliness classification for hydraulic fluids
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8625-1, ISO 8625-2, and
ISO 8625-3 and the following apply.
NOTE See ISO 8278 for terms and definitions that relate to the variable delivery hydraulic pump.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
electric motor driven variable delivery, hydraulic pump
EMP
hydraulic pump driven by an electric motor that is able to supply hydraulic power to the hydraulic
system (or sub-system) to meet a variety of functions within the aircraft system
Note 1 to entry: Examples of these functions are listed below:
— as the primary power source for the hydraulic system to supply fluid as demanded by the system, either
continuously operating or switched on for particular phases of the aircraft operation e.g. for take-off and
landing;
— as a back-up source when the primary source has failed; and
— as a power source to be used when the aircraft is on the ground to operate various utility functions or for
ground maintenance purposes.
Note 2 to entry: To operate the EMP, the electrical supply may be derived from various electrical sources,
including the main engine driven generators, auxiliary power unit driven generators, or ground cart generators.
3.2
purchaser
organization that has the engineering responsibility for the hydraulic system that includes the pump
Note 1 to entry: Typically, the purchaser is an aircraft manufacturer, an equipment manufacturer that has
hydraulic system responsibility or a modification centre.
Note 2 to entry: The purchaser is responsible for the compilation of the detail specification.
3.3
detail specification
document compiled by the purchaser that specifies:
— technical requirements;
— acceptance and qualification test requirements;
— reliability requirements;
— quality requirements;
— packaging requirements; and
— other requirements.
2 © ISO 2017 – All rights reserved

3.4
supplier
organization that provides the EMP
Note 1 to entry: Typically, the purchaser is the manufacturer of the EMP who will be responsible for the design,
production and qualification of the pump.
3.5 Ports of the hydraulic pump
3.5.1
pump inlet port
port that receives flow from the hydraulic reservoir to supply the pump
3.5.2
pump discharge port
port that supplies pressurised flow to the system
3.5.3
pump case drain port
port that drains internal leakage flow to the reservoir
3.5.4
shaft seal port
port that routes any shaft seal leakage from the pump to an overboard drain, collector tank etc.
3.6 Temperature terms
3.6.1
rated temperature
maximum continuous temperature of the fluid to be supplied at the supply port of the pump
Note 1 to entry: The rated temperature is expressed in degrees centigrade.
3.6.2
minimum continuous temperature
minimum temperature of the fluid at the supply port of the pump at which the pump is able to function
Note 1 to entry: The minimum continuous temperature is expressed in degrees centigrade.
Note 2 to entry: This temperature is generally higher than the survival temperature.
3.7 Pressure terms
3.7.1
design operating pressure
normal maximum steady pressure
Note 1 to entry: Excluded are reasonable tolerances, transient pressure effects such as may arise from:
— pressure ripple;
— reactions to system functioning; and
— demands that may affect fatigue.
3.7.2 Inlet pressure
3.7.2.1
rated inlet pressure
minimum pressure measured at the inlet port of the EMP at which the pump is required to provide
performance without any degradation, with all other parameters at their rated values, except for the
fluid temperature, which is the minimum continuous temperature
3.7.2.2
maximum inlet pressure
maximum steady state inlet pressure at which the EMP may be required to operate
3.7.2.3
minimum inlet pressure
lowest pump inlet port pressure, specified by the purchaser, for which the supplier ensures that the
EMP might be required to operate without cavitation during a system failure or during a system high-
flow transient condition
Note 1 to entry: For the purposes of this document, cavitation is assumed to occur when there is a 2 % reduction
in discharge flow with reducing inlet pressure.
3.7.3
discharge pressure
maximum pressure against which the EMP is required to operate continuously at:
— rated supply voltage;
— rated supply frequency;
— rated fluid temperature;
— rated inlet pressure;
— rated case drain pressure;
— zero flow; and
— using the hydraulic fluid specified in the detail specification.
Note 1 to entry: The diagram in Figure 1 is given as an indication. It may be presented in a different way, for
example, the axes may be reversed.
4 © ISO 2017 – All rights reserved

Key
1 differential pressure type pump characteristics A rated pressure
2 constant pressure type pump characteristics B minimum flow at maximum pressure point
3 constant pressure type pump characteristics B* cut-off pressure for constant pressure pump
4 constant power type pump characteristics C full flow at minimum pressure point
5 increasing power and weight D maximum flow point
X flow in l/min
Y pressure in kPa
Figure 1 — Discharge pressure
3.7.3.1
maximum full-flow pressure
maximum discharge pressure at which the EMP pump control will not be acting to reduce pump
discharge, at rated temperature, rated speed, rated inlet and case drain pressure
3.7.3.2
maximum EMP discharge transient pressure
peak value of the discharge pressure recorded during a discrete transient event (normally found whilst
cycling from full-flow pressure to rated pressure (zero flow))
3.7.3.3
pressure pulsations
oscillations of the EMP pump discharge pressure, occurring during nominally steady operating conditions,
at a frequency equal to the number of pistons times the drive shaft speed, or a multiple thereof
Note 1 to entry: The amplitude of the oscillations is the difference between the average minimum and the average
maximum oscillations recorded during a one-second trace.
3.7.4 Case drain pressure
3.7.4.1
maximum case drain pressure
maximum continuous pressure developed by the EMP to enable case drain fluid to return to the
reservoir
3.7.4.2
rated case drain pressure
nominal pressure at which the EMP case is required to operate continuously in the system
3.7.4.3
maximum transient case drain pressure
maximum pressure peak that can be imposed by the hydraulic system on the EMP case drain port
3.8
rated discharge flow
flow rate measured at the EMP delivery port under conditions of:
— rated supply voltage;
— rated supply frequency;
— rated fluid temperature;
— rated inlet pressure;
— rated case drain pressure;
— maximum full-flow pressure; and
— using the hydraulic fluid specified in the detail specification.
Note 1 to entry: The flow shall be measured in the compressed state.
3.9
rated displacement
maximum theoretical volume of fluid generated by one revolution of the EMP pump drive shaft at
full stroke
Note 1 to entry: The rated displacement shall be calculated from the geometrical configuration of the pump,
without allowing for the effects of:
— permissible manufacturing tolerances;
— distortions of the pump structure;
— the compressibility of the hydraulic fluid;
— internal leakage; and
— temperature.
Note 2 to entry: The rated displacement is used to indicate the size of the pump rather than its performance.
3.10
rated speed
maximum speed at which the EMP pump will operate at based on:
— maximum AC supply frequency;
— rated voltage.
Note 1 to entry: The rated speed is expressed as a number of revolutions of the pump drive shaft per minute.
3.11
response time
time interval between the moment when an increase (or decrease) of the EMP delivery pressure begins
and the subsequent time when the delivery pressure reaches its first maximum (or minimum) value,
when connected to a specified circuit
6 © ISO 2017 – All rights reserved

3.12
stability
freedom from persistent or quasi-persistent oscillation or “hunting” of the EMP (cyclic variations in
pressure) at any frequency that can be traced to the delivery control mechanism, within stated limits in
the detail specification
3.13 Electrical terms
3.13.1
nominal electric supply condition
nominal system voltage and frequency without consideration of any distribution drop or cable
impedance
3.13.2
starting in-rush current
RMS value of the current ignoring any initial half cycle transient effects
3.13.3
voltage drop
reduction in voltage across a given wire length for each phase of an AC electrical supply
3.14
EMP overall efficiency
ratio of the EMP pump output fluid power to the EMP electric motor input electrical power when the
EMP is operating at rated conditions or any other operating conditions if so specified in the detail
specification. It is derived from the following formula:
EMP overall effiency (%) = [( Δ×PQpp )/(VI ×φ cos )] × 1000 (1)
where
ΔP differential pressure between the EMP pump delivery and inlet ports (kPa);
p
Q EMP pump delivery flow (l/min);
p
V supply Voltage (volts) for AC volts the Root Mean Square (RMS) value shall be used;
I supply Current (amps) for AC current the Root Mean Square (RMS) value shall be used;
Φ phase angle between voltage and current
Note 1 to entry: This equation ignores compressibility effects. If this equation is to be used, the flow rate
measurement should be made on the compressed flow stream.
Note 2 to entry: For a three-phase AC supply, the power should be derived from the summation of the powers
for each phase, i.e. V I +V I +V I multiplied by the power factor (cos ϕ). For a balanced supply, the input power
A A B B C C
equates to (3 × V × I cos ϕ).
A A
3.15
rated endurance
total number of hours and cycles of operation to be included in the endurance phase of its
qualification testing
3.16
first article inspection
FAI
process that conducts:
— verifies that the parts of a component comply with the drawings;
— verifies that the manufacturing processes have been compiled and are adhered to;
— verifies that the assembly processes have been compiled and are adhered to; and
— verifies that the acceptance test of the component is in accordance with the test procedure, and that
the results of the test are in agreement with the test requirements
4 General requirements
4.1 Order of precedence
The detail specification shall take precedence in the case of a conflict between the requirements of this
document and the detail specification.
4.2 Electrical system characteristics
The detail specification shall define the range of electrical supply characteristics for normal and
abnormal operation. This shall include any of the normal faults such as power interruption. Any
deviation from the nominal performance due to variations in the electrical supply shall be agreed
between the supplier and the purchaser as early as possible in the design phase. The effect of the
aircraft feeder cables shall be considered as part of the electrical supply.
4.3 Hydraulic system characteristics
The detail specification shall include the characteristics of the hydraulic system in which the EMP is to
be used in order to assist in the integration of the EMP into the hydraulic system.
The detail specification shall include the characteristics of the hydraulic system in which the pump is to
be used. This shall include the flow versus pressure curves for the inlet, discharge and case drain lines
for the following hydraulic fluid temperatures:
— normal operating temperature;
— rated temperature; and
— minimum continuous temperature.
4.4 Airworthiness requirements
The EMP shall comply with the applicable airworthiness requirements.
4.5 Qualification
EMPs furnished under this document shall be products that have passed the qualification tests specified
in the detail specification.
5 Functional requirements
5.1 Functional requirements - electrical
5.1.1 AC power requirements
5.1.1.1 General
The power supply should be compliant with the specifications provided in ISO 1540. Any non-
compliance should be defined in the detail specification.
8 © ISO 2017 – All rights reserved

5.1.1.2 Rated voltage
The detail specification shall define the rated voltage at the point of regulation (POR), taking into
consideration all potential sources of power that will be applied to the EMP. The rated voltage shall be
defined at the interface with the EMP, i.e. at the electrical connector. The rated voltage range shall be
defined under normal operating conditions and the minimum shall be defined for start-up.
The rated voltage at the POR shall be defined and will typically be a nominal value of either 115 or
230 V AC per phase (single
...