IEC 61881-2:2012

Railway applications - Rolling stock equipment - Capacitors for power electronics - Part 2: Aluminium electrolytic capacitors with non-solid electrolyte

IEC 61881-2:2012 applies to d.c. aluminium electrolytic capacitors (cell, module and bank) for power electronics intended to be used on rolling stock. It specifies quality requirements and tests, safety requirements, and describes installation and operation information.

Applications ferroviaires - Matériel roulant - Condensateurs pour électronique de puissance - Partie 2: Condensateurs électrolytiques à l'aluminium, à électrolyte non solide

La CEI 61881-2:2012 s'applique aux condensateurs électrolytiques à l'aluminium en courant continu (unité, module et batterie) pour électronique de puissance, destinés à être utilisés sur le matériel roulant. Elle spécifie les exigences relatives à la qualité et les essais, ainsi que les exigences de sécurité, et elle fournit des informations sur l'installation et les conditions de fonctionnement.

General Information

• Status: Published
• Publication Date: 07-Aug-2012
• ICS: 45.060.01 - Railway rolling stock in general
• Technical Committee: TC 9 - Electrical equipment and systems for railways
• Drafting Committee: WG 47 - TC 9/WG 47
• Current Stage: PPUB - Publication issued
• Start Date: 31-Aug-2012
• Completion Date: 08-Aug-2012

Overview

IEC 61881-2:2012 is an international standard published by the International Electrotechnical Commission (IEC) that addresses aluminium electrolytic capacitors with non-solid electrolyte used in railway applications, specifically for rolling stock power electronics. This standard defines quality and safety requirements, testing procedures, and guidance for installation and operation. It ensures that these capacitors meet the necessary performance and reliability criteria for use in demanding railway environments, supporting the efficient and safe operation of rolling stock electrical equipment.

Key Topics

• Scope and Application

  • Covers DC aluminium electrolytic capacitors including cells, modules, and banks designed for power electronics in railway rolling stock.
  • Focuses on capacitors with non-solid electrolyte chemistry.

• Service Conditions

  • Specifies normal and unusual service conditions such as altitude, temperature ranges, and environmental stresses relevant to railway operations.

• Quality and Test Requirements

  • Details classifications of tests including type, routine, and acceptance tests.
  • Includes measurements of capacitance, leakage current, insulation resistance, sealing, thermal endurance, mechanical robustness, and environmental resilience.

• Safety Requirements

  • Addresses discharge devices, grounding of capacitor cases, environmental protection, and passive flammability to minimize risks during operation.

• Marking and Documentation

  • Defines marking requirements for capacitors and the data sheet information necessary for proper identification and usage.

• Installation and Operation Guidance

  • Provides recommendations for rated voltage selection, operating temperature considerations, cooling, overload conditions, connection methods (series, parallel), and protective device requirements.
  • Includes instructions to ensure capacitor longevity and reliable performance in rolling stock power electronics.

Applications

IEC 61881-2:2012 capacitors are critical components within power electronic systems of railway rolling stock, such as:

• Traction converters and inverters
• Auxiliary power supplies
• Energy storage and filtering circuits
• Electrical systems requiring reliable DC capacitor banks to manage voltage stability

These capacitors contribute to maintaining the electrical efficiency, safety, and durability of power electronics in trains and other rolling stock, which operate under harsh mechanical vibrations, temperature variations, and electrical stress conditions.

Related Standards

• IEC 61881-1: Applies to capacitors for power electronics with solid electrolyte, complementing Part 2 on non-solid types.
• IEC 60068 series: Environmental testing standards often referenced in capacitor testing for temperature, humidity, vibration, and shock.
• IEC 60071 series: Addresses insulation coordination related to voltage rating and surge withstand, relevant for capacitor safety.
• IEC 60384 series: General standards for fixed capacitors used in electronic equipment.
• ISO/TS 22163: Railway industry quality management systems applicable to components like capacitors.

---

Keywords: IEC 61881-2, aluminium electrolytic capacitor, railway applications, rolling stock equipment, power electronics, non-solid electrolyte capacitor, capacitor testing, capacitor safety, installation guidance, railway power systems.

Standards Content (Sample)

IEC 61881-2 ®
Edition 1.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Rolling stock equipment – Capacitors for power
electronics –
Part 2: Aluminium electrolytic capacitors with non-solid electrolyte

Applications ferroviaires – Matériel roulant – Condensateurs pour électronique
de puissance –
Partie 2: Condensateurs électrolytiques à l’aluminium, à électrolyte non solide

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IEC 61881-2 ®
Edition 1.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Railway applications – Rolling stock equipment – Capacitors for power

electronics –
Part 2: Aluminium electrolytic capacitors with non-solid electrolyte

Applications ferroviaires – Matériel roulant – Condensateurs pour électronique

de puissance –
Partie 2: Condensateurs électrolytiques à l’aluminium, à électrolyte non solide

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 45.060 ISBN 978-2-83220-259-3

– 2 – 61881-2 © IEC:2012
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Service conditions . 10
4.1 Normal service conditions . 11
4.1.1 General . 11
4.1.2 Altitude . 11
4.1.3 Temperature . 11
4.2 Unusual service conditions . 11
5 Quality requirements and tests . 12
5.1 Test requirements . 12
5.1.1 General . 12
5.1.2 Test conditions . 12
5.1.3 Measurement conditions . 12
5.1.4 Voltage treatment . 12
5.1.5 Thermal treatment . 12
5.2 Classification of tests . 12
5.2.1 General . 12
5.2.2 Type tests . 13
5.2.3 Routine tests . 13
5.2.4 Acceptance tests . 14
5.3 Capacitance and tangent of loss angle (tanδ) . 14
5.3.1 Capacitance . 14
5.3.2 Tangent of loss angle (tanδ) . 14
5.4 Leakage current . 14
5.4.1 Capacitor cell . 14
5.4.2 Capacitor module or bank . 14
5.5 Insulation test between terminals and case . 14
5.5.1 Capacitor cell . 14
5.5.2 Capacitor module or bank . 15
5.6 Sealing test . 15
5.7 Surge discharge test (under consideration) . 15
5.7.1 General . 15
5.7.2 Preconditioning. 15
5.7.3 Initial measurement . 15
5.7.4 Test methods . 15
5.7.5 Post treatment . 16
5.7.6 Final measurement . 16
5.7.7 Acceptance criteria . 16
5.8 Environmental testing . 16
5.8.1 Change of temperature . 16
5.8.2 Damp heat, steady state . 17
5.9 Mechanical testing . 18
5.9.1 Mechanical tests of terminals . 18

61881-2 © IEC:2012 – 3 –
5.9.2 External inspection . 18
5.9.3 Vibration and shocks . 18
5.10 Endurance test . 18
5.10.1 General . 18
5.10.2 Preconditioning. 18
5.10.3 Initial measurements . 18
5.10.4 Test methods . 18
5.10.5 Post treatment . 19
5.10.6 Final measurement . 19
5.10.7 Acceptance criteria . 19
5.11 Pressure relief test . 19
5.12 Passive flammability . 19
6 Overloads . 19
6.1 Maximum permissible voltage . 19
6.2 Maximum permissible current . 20
7 Safety requirements . 20
7.1 Discharge device . 20
7.2 Case connections (grounding) . 20
7.3 Protection of the environment . 20
7.4 Other safety requirements . 20
8 Marking . 21
8.1 Marking of the capacitor . 21
8.1.1 Capacitor cell . 21
8.1.2 Capacitor module or bank . 21
8.2 Data sheet . 21
9 Guidance for installation and operation . 22
9.1 General . 22
9.2 Choice of rated voltage . 22
9.3 Operating temperature . 22
9.3.1 Life time of capacitor . 22
9.3.2 Installation . 22
9.3.3 Unusual cooling conditions . 23
9.4 Over voltages . 23
9.5 Overload currents . 23
9.6 Switching and protective devices . 23
9.7 Dimensioning of creepage distance and clearance . 24
9.8 Connections . 24
9.9 Parallel connections of capacitors . 24
9.10 Series connections of capacitors . 24
9.11 Magnetic losses and eddy currents . 24
9.12 Guide for unprotected capacitors . 24
Annex A (informative) Terms and definitions of capacitors . 25
Bibliography . 26

Figure 1 – Examples of preferred vent and anode position . 23
Figure A.1 – Example of capacitor application in capacitor equipment . 25

Table 1 – Classification of tests . 13

– 4 – 61881-2 © IEC:2012
Table 2 – Damp heat steady-state test . 17
Table 3 – Testing the robustness of terminals . 18

61881-2 © IEC:2012 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RAILWAY APPLICATIONS –
ROLLING STOCK EQUIPMENT –
CAPACITORS FOR POWER ELECTRONICS –

Part 2: Aluminium electrolytic capacitors with non-solid electrolyte

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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6) All users should ensure that they have the latest edition of this publication.
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Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61881-2 has been prepared by technical committee 9: Electrical
equipment and systems for railways.
The text of this standard is based on the following documents:
FDIS Report on voting
9/1679/FDIS 9/1707/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – 61881-2 © IEC:2012
A list of all parts of IEC 61881 series, under the general title Railway applications – Rolling
stock equipment – Capacitors for power electronics, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61881-2 © IEC:2012 – 7 –
RAILWAY APPLICATIONS –
ROLLING STOCK EQUIPMENT –
CAPACITORS FOR POWER ELECTRONICS –

Part 2: Aluminium electrolytic capacitors with non-solid electrolyte

1 Scope
This part of IEC 61881 applies to d.c. aluminium electrolytic capacitors (cell, module and
bank) for power electronics intended to be used on rolling stock.
This standard specifies quality requirements and tests, safety requirements, and describes
installation and operation information.
NOTE Example of the application for capacitors specified in this Standard; d.c. filtering, etc.
Capacitors not covered by this Standard:
– IEC 61881-1: Paper/plastic film capacitors;
– IEC 61881-3: Electric double-layer capacitors.
Guidance for installation and operation is given in Clause 9.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60062:2004, Marking codes for resistors and capacitors
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-17:1994, Environmental testing – Part 2-17: Tests. Test Q: Sealing
IEC 60068-2-20, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leads
IEC 60068-2-21:2006, Environmental testing – Part 2-21: Tests – Test U: Robustness of
terminations and integral mounting devices
IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 60384-1:2008, Fixed capacitors for use in electronic equipment – Part 1: Generic
specification
IEC 60384-4:2007, Fixed capacitors for use in electronic equipment – Part 4: Sectional
specification – Aluminium electrolytic capacitors with solid (MnO ) and non-solid electrolyte
– 8 – 61881-2 © IEC:2012
IEC 60721-3-5:1997, Classification of environmental conditions – Part 3: Classification of
groups of environmental parameters and their severities – Section 5: Ground vehicle
installations
IEC 61373:2010, Railway applications – Rolling stock equipment – Shock and vibration tests
IEC 62497-1, Railway applications – Insulation coordination – Part 1: Basic requirements –
Clearances and creepage distances for all electrical and electronic equipment
IEC 62498-1:2010, Railway applications – Environmental conditions for equipment – Part 1:
Equipment on board rolling stock
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
capacitor element
indivisible electrolytic capacitor with non-solid electrolyte
3.2
capacitor cell
one or more capacitor elements, packaged in the same enclosure with terminals brought out
SEE: Annex A
3.3
capacitor module
assembly of two or more capacitor cells, electrically connected to each other with or without
additional electronics
SEE: Annex A
3.4
capacitor bank
assembly of two or more capacitor modules
SEE: Annex A
3.5
capacitor
general term used when it is not necessary to state whether reference is made to capacitor
cell, module or bank
[SOURCE: IEC 61881-1:2010, 3, modified]
3.6
capacitor equipment
assembly of capacitor banks and their accessories intended for connection to a network
SEE: Annex A
3.7
capacitor for power electronics
capacitor intended to be used in power electronic equipment and capable of operating
continuously under sinusoidal and non-sinusoidal current and voltage
Note 1 to entry: Capacitor in this standard is d.c. capacitor.

61881-2 © IEC:2012 – 9 –
3.8
aluminium electrolytic capacitor with non-solid electrolyte
capacitor consisting of oxide film formed on the surface of aluminium foil by anodic oxidation
as dielectric and paper or fibber impregnated with liquid electrolyte in close contact with the
dielectric as a part of the cathode
3.9
pressure relief structure
mechanism to release internal pressure of capacitor when exceeding the specified value
3.10
discharge device
device which can reduce the voltage between the terminals practically to zero, within a given
time, after the capacitor has been disconnected from a network
3.11
rated d.c. voltage (U )
R
maximum d.c. voltage which may be applied continuously to a capacitor at any temperature
between the Iower category temperature and the upper category temperature
[SOURCE: IEC 60384-1:2008, 2.2.16, modified]
Note 1 to entry: In typical traction application, the maximum voltage is the sum of the d.c. voltage and peak a.c.
voltage or peak pulse voltage applied to the capacitor.
3.12
insulation voltage (U )
i
r.m.s. value of the sine wave voltage designed for the insulation between terminals of
capacitors to case or earth. If not specified, r.m.s. value of the insulating voltage is equivalent
to the rated voltage divided by √2
3.13
maximum peak current (I )
P
maximum peak current that can occur during continuous operation
3.14
rated ripple current (I )
ripple
the r.m.s value of the maximum allowable alternating current of a specified frequency, at
which the capacitor may be operated continuously at a specified temperature
3.15
maximum surge current (I )
s
peak non-repetitive current induced by switching or any other disturbance of the system which
is allowed for a limited number of times
Note 1 to entry: See surge voltage in IEC 60384-4:2007, 4.14.
3.16
operating temperature
temperature of the hottest point on the case of the capacitor when in steady-state conditions
of temperature
SEE: 3.22
3.17
ambient temperature
temperature of the air surrounding the non-heat dissipating capacitor or temperature of the air
in free air conditions at such a distance from the heat dissipating capacitor that the effect of
the dissipation is negligible
– 10 – 61881-2 © IEC:2012
3.18
upper category temperature
highest ambient temperature including internal heating in which a capacitor is designed to
operate continuously
3.19
lower category temperature
lowest ambient temperature including internal heating in which a capacitor is designed to
operate continuously
3.20
case temperature rise (ΔT )
case
difference between the temperature of the hottest point of the case and the temperature of the
cooling air under the steady-state conditions of temperature
3.21
cooling-air temperature (T )
amb
temperature of the cooling air measured at the inlet, under the steady-state condition of
temperature
3.22
maximum operating temperature (T )
max
highest temperature of the case at which the capacitor may be operated
Note 1 to entry: The temperature is different from upper category temperature.
3.23
steady-state conditions of temperature
thermal equilibrium attained by the capacitor at constant output and at constant coolant
temperature
3.24
tangent of the loss angle of a capacitor
tan
power loss of the capacitor divided by the reactive power of the capacitor at a sinusoidal
voltage at a specified frequency
[SOURCE: IEC 60384-1:2008, 2.2.24]
R R
esr esr
tanδ = ＝ =2πfC ×R
esr
1 1
ωC 2πfC
where R is the equivalent series resistance;
esr
ω is the angular frequency (2×π×f);
C is the capacitance.
3.25
equivalent series resistance of a capacitor (R )
esr
effective resistance which, if connected in series with an ideal capacitor of capacitance value
equal to that of the capacitor in question, would have a power loss equal to active power
dissipated in that capacitor under specified operating conditions
4 Service conditions
NOTE See IEC 60077-1.
61881-2 © IEC:2012 – 11 –
4.1 Normal service conditions
4.1.1 General
This standard gives requirements for capacitors intended for use in the following conditions:
4.1.2 Altitude
Not exceeding 1 400 m. See IEC 62498-1.
NOTE The effect of altitude on cooling air characteristics and insulation clearance should be taken into
consideration, if the altitude exceeds 1 400 m.
4.1.3 Temperature
The climatic ambient temperatures are derived from IEC 60721-3-5:1997 class 5k2 which has
a range from –25 °C to 40 °C. Where ambient temperature lies outside this range, it shall be
agreed between the purchaser and the manufacturer.
NOTE Classes of temperature are listed in IEC 62498-1:2010, Table 2.
4.2 Unusual service conditions
This standard does not apply to capacitors, whose service conditions are such as to be in
general incompatible with its requirements, unless otherwise agreed between the
manufacturer and the purchaser.
Unusual service conditions require additional measurements, which ensure that the conditions
of this standard are complied with even under these unusual service conditions.
If such unusual service conditions exist then they shall be notified to the manufacturer of the
capacitor.
Unusual service conditions can include:
– unusual mechanical shocks and vibrations;
– corrosive and abrasive particles in the cooling air;
– dust in the cooling air, particularly if conductive;
– explosive dust or gas;
– oil or water vapour or corrosive substances;
– nuclear radiation;
– unusual storage or transport temperature;
– unusual humidity (tropical or subtropical region);
– excessive and rapid changes of temperature (more than 5 K/h) or of humidity (more than
5 %/h);
– service areas higher than 1 400 m above sea level;
– superimposed electromagnetic fields;
– excessive over voltages, as far as they exceed the limits given in Clause 6 and in 9.4;
– airtight (poor change of air) installations.

– 12 – 61881-2 © IEC:2012
5 Quality requirements and tests
5.1 Test requirements
5.1.1 General
This subclause gives the test requirements for capacitors.
5.1.2 Test conditions
Unless otherwise specified, the test conditions shall be as in IEC 60384-1:2008, 4.2.1.
NOTE IEC 60384-1:2008, 4.2.1 specifies the following standard atmospheric conditions for measurements and
tests.
Temperature: 15 °C to 35 °C
Relative humidity: 25 % to 75 %
Air pressure: 86 kPa to 106 kPa.
5.1.3 Measurement conditions
The measurement conditions (i.e. capacitance, tangent of loss angle and leakage current,
etc.) for the capacitor shall be as in IEC 60384-4:2007, 4.2.3 with the following exceptions.
The temperature shall be 25 °C ± 2 °C.
Relative humidity shall be 25 % to 75 %.
5.1.4 Voltage treatment
The capacitor shall be subjected to voltage treatment as specified in IEC 60384-4:2007, 4.1.
Then the capacitor shall be discharged through a suitable discharge device.
5.1.5 Thermal treatment
The capacitor shall be placed in the environment at the temperature of 5.1.3 for a suitable
soak period for thermal equalization.
NOTE Leave time of capacitor to reach measuring condition may be generally 1 h to 4 h for capacitor cell and 4 h
to 24 h for capacitor module and bank.
5.2 Classification of tests
5.2.1 General
The tests are classified as type tests, routine tests and acceptance tests:
The type tests and the routine tests consist of tests shown in Table 1.

61881-2 © IEC:2012 – 13 –
Table 1 – Classification of tests
No. Tests item Type tests Routine tests
Cell Module or bank Cell Module or bank
1A Capacitance 5.3 5.3 5.3 5.3
1B Tangent of loss angle 5.3 5.3 5.3 5.3
2 Leakage current 5.4 5.4 5.4 5.4
a a
3 Insulation test between 5.5.1 5.5.2 5.5.1 5.5.2
terminals and case (if applicable and (if applicable)
required )
4 Sealing test 5.6 ― ― ―
5 Surge discharge test 5.7 5.7 ― ―
(if applicable)
6 Change of temperature 5.8.1 5.8.1 ― ―
b
7 Damp heat, steady state 5.8.2 5.8.2 ― ―
(if applicable) (module only)
a
8 Mechanical tests of 5.9.1 5.9.1 ― ―
terminals (if applicable)
9 External inspection 5.9.2 5.9.2 5.9.2 5.9.2
10 Vibration and shocks 5.9.3 5.9.3 ― ―
11 Endurance test 5.10 ― ― ―
12 Pressure relief test 5.11.1 ― ― ―
(if applicable)
13 Passive flammability 5.12 ― ― ―
a
This test may be substituted by module or bank test, when agreed between the manufacturer and the
purchaser.
b
This test may be substituted by capacitor cell test, when agreed between the manufacturer and the purchaser.

5.2.2 Type tests
Type tests are intended to prove the soundness and safety of the design of the capacitor and
its suitability for operation under the conditions detailed in this standard.
The type tests shall be carried out by the manufacturer, and the purchaser shall, on request,
be supplied with a certificate, detailing the results of such tests.
These tests shall be made upon capacitors which are designed identical to that of the
capacitor defined in the contract.
In agreement between the manufacturer and the purchaser, a capacitor of a similar design
can be used, when the same or more severe test conditions can be applied.
It is not essential that all type tests be carried out on the same capacitor sample. The choice
is left to the manufacturer.
5.2.3 Routine tests
The tests sequence for quality requirements shall be as follows:
Routine tests shall be carried out by the manufacturer on every capacitor before delivery.
Upon request, the manufacturer shall deliver the capacitor with certification detailing the
results of the tests.
– 14 – 61881-2 © IEC:2012
5.2.4 Acceptance tests
All or a part of the type tests and the routine tests may be carried out by the manufacturer, on
agreement with the purchaser.
The number of samples that may be subjected to such repeat tests, the acceptance criteria,
as well as permission to deliver any of these capacitors shall be subject to agreement
between the manufacturer and the purchaser, and shall be stated in the contract.
5.3 Capacitance and tangent of loss angle (tanδ)
5.3.1 Capacitance
The capacitance of the capacitor shall be measured in accordance with IEC 60384-4:2007,
4.3.2 after the leakage current measurement (see 5.4).
The capacitance of the capacitor shall be within the capacitance tolerance agreed between
the manufacturer and the purchaser.
5.3.2 Tangent of loss angle (tanδ)
The tangent of loss angle (tanδ) of the capacitor shall be measured in accordance with
IEC 60384-4:2007, 4.3.3 after leakage current measurement (see 5.4).
The tangent of loss angle of the capacitors shall not exceed the values agreed between the
manufacturer and the purchaser.
5.4 Leakage current
5.4.1 Capacitor cell
Unless otherwise specified, the capacitor cell shall be tested in accordance with
IEC 60384-4:2007, 4.3.1 with the following details.
Before this measurement is made, the capacitors cell shall be fully discharged.
The duration of connecting voltage shall be measured in accordance with the time as agreed
between the manufacturer and the purchaser.
During the test, neither electrical breakdown of the insulation nor flashover shall occur.
5.4.2 Capacitor module or bank
The capacitor module or bank shall be tested as agreed between the manufacturer and the
purchaser.
5.5 Insulation test between terminals and case
5.5.1 Capacitor cell
Unless otherwise agreed between the manufacturer and the purchaser, the measurement for
the capacitor shall be in accordance with IEC 60384-1:2008, 4.6.2.3, with the following details:
Measurement section: between the two terminations connected together and non-metallic
case of capacitor,
a) test voltage: voltage agreed between the manufacturer and the purchaser;
b) test duration: 1 min, unless otherwise agreed between the manufacturer and the
purchaser.
61881-2 © IEC:2012 – 15 –
For each of the specified test points there shall be no sign of breakdown or flashover during
the test period.
5.5.2 Capacitor module or bank
Unless otherwise specified, the tests of capacitor shall be carried out in accordance with
IEC 62497-1 with the following exception:
The test duration shall be 10 s.
5.6 Sealing test
Unless the sealing capability of the capacitor cell has been proved otherwise, the sealing test
shall be carried out according to test Qc, method 2 in IEC 60068-2-17:1994, using non-
conductive silicon oil or equivalent solvent as an examination solvent.
The capacitor cell shall be immersed in an examination solvent with the sealing parts of the
capacitor cell facing up. The temperature of examination solvent shall be 5 °C higher than the
operating temperature.
The immersion time for the capacitor cell shall be 3 times or more the thermal time constant
for the capacitor cell.
No continuous generation of air bubbles in the examination solvent shall be coming from the
sealing parts of the capacitor cell. If the judgment is in doubt, the test shall be performed without
sleeve.
5.7 Surge discharge test (under consideration)
5.7.1 General
Unless otherwise specified, the surge discharge test for the capacitor shall be carried out by
following procedure.
5.7.2 Preconditioning
The capacitor shall be treated in accordance with 5.1.4 and then 5.1.5.
5.7.3 Initial measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.7.4 Test methods
The capacitor shall be charged by means of a d.c. source up to 1,1 U within 5 min and then
R
discharged through a suitable discharge circuit within 1 min. The test shall be repeated
5 times. The test intervals should be within 6 min.
The resistance of the discharge circuit (cables, switches, shunts or electronic) shall have a
maximum resistance equal to the internal resistance of capacitor cell, but not higher than
1 mΩ.
If, however, a maximum surge current is specified, the discharge current shall be adjusted by
variation of the impedance of discharge circuit to a value of:
I = 1,1 I
test s
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5.7.5 Post treatment
The capacitor shall be treated in accordance with 5.1.5, and discharged through a suitable
discharge device.
5.7.6 Final measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.7.7 Acceptance criteria
The capacitance change of the capacitor shall be within the values agreed between the
manufacturer and the purchaser.
The leakage current and tangent of loss angle of the capacitor shall not exceed the values
agreed between the manufacturer and the purchaser.
5.8 Environmental testing
5.8.1 Change of temperature
5.8.1.1 General
Unless otherwise specified, the change of temperature test for the capacitor shall be carried
out by the following procedure.
5.8.1.2 Preconditioning
The capacitor shall be treated in accordance with 5.1.4 and the 5.1.5.
5.8.1.3 Initial measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.8.1.4 Test methods
The change of temperature test for the capacitor shall be carried out in accordance with test
Na of IEC 60068-2-14:2009, on agreement between the manufacturer and the purchaser with
the upper and lower limit temperature of the capacitor with following details.
a) Upper limit temperature: Upper category temperature
b) Lower limit temperature: Lower category temperature
c) Number of cycles: As agreed between the manufacturer and the purchaser
5.8.1.5 Post treatment
The capacitor shall be treated in accordance with 5.1.5 and discharged through a suitable
discharge device.
5.8.1.6 Final measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.8.1.7 Acceptance criteria
The capacitance change of the capacitor shall be within the values as agreed between the
manufacturer and the purchaser.

61881-2 © IEC:2012 – 17 –
The leakage current and tangent of loss angle of the capacitor shall not exceed the values as
agreed between the manufacturer and the purchaser.
5.8.2 Damp heat, steady state
5.8.2.1 General
Unless otherwise specified, the damp heat, steady state test for the capacitor shall be carried
out by the following procedure.
5.8.2.2 Preconditioning
The capacitor shall be treated in accordance with 5.1.4 and 5.1.5.
5.8.2.3 Initial measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.8.2.4 Test methods
The test shall be carried out in accordance with IEC 60068-2-78 and a degree of severity (see
Table 2) as agreed between the manufacturer and the purchaser. No condensation shall occur
during the test.
Table 2 – Damp heat steady-state test
Severity Test temperature Test humidity Duration
°C % RH Days
A 40 93 56
B 40 93 21
After completion of the steady-state test, the capacitor cell (if applicable) or module shall be
subjected to insulation test between terminals and case according to 5.5.
5.8.2.5 Post treatment
The capacitor shall be treated in accordance with 5.1.5 and discharged through a suitable
discharge device.
5.8.2.6 Final measurement
The capacitance and tangent of loss angle, and the leakage current of the capacitor shall be
measured in accordance with 5.3 and 5.4 respectively.
5.8.2.7 Acceptance criteria
No test sample shall suffer electric break down of insulation or flashover during insulation test
between terminals and case (see 5.5).
The capacitance change of the capacitor shall be within the values as agreed between the
manufacturer and the purchaser.
The leakage current and tangent of loss angle of the capacitor shall not exceed the values as
agreed between the manufacturer and the purchaser.

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5.9 Mechanical testing
5.9.1 Mechanical tests of terminals
The capacitor shall be tested for appropriate robustness of terminals as agreed between the
manufacturer and the purchaser (see Table 3).
Table 3 – Testing the robustness of terminals
No. Tests or measurements Test method Test conditions
Tensile strength of connecting Ua Individual with capacitor
1 cables and soldered connections weight, at least 10 N
2 Ub Number of flexing cycles: 2
Flexural strength of connections
3 Flexural strength of soldering and Ub Number of bending cycles,
flat plug lugs for soldered lugs with
IEC 60068-
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