ASTM B854-98
(Guide)Standard Guide for Measuring Electrical Contact Intermittences
Standard Guide for Measuring Electrical Contact Intermittences
SCOPE
1.1 The techniques described in this guide apply to electrical circuits that include one or more electrical contacts in devices such as slip rings, separable connectors, electromechanical relays or closed switch contacts. The user should determine applicability for other devices.
1.2 The range of techniques described apply to circuit discontinuities (intermittences) of durations ranging from approximately 10 nanoseconds to several seconds and of sufficient magnitude to cause alteration of the circuit function. Extension of the guide to shorter duration events may be possible with suitable instrumentation. Events of longer duration may be monitored by techniques for dc measurements such as those described in Test Methods B539 or by adaptation of methods described in this guide.
1.3 The techniques described in this guide apply to electrical circuits carrying currents typical of signal circuits. Such currents are generally less than 100 ma. Extension of these techniques to circuits carrying larger currents may be possible, but the user should evaluate applicability first.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: B 854 – 98
Standard Guide for
Measuring Electrical Contact Intermittences
This standard is issued under the fixed designation B 854; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Other Documents:
IEC Publication 512, Test 2e Contact Disturbance
1.1 The techniques described in this guide apply to electri-
EIA-364-46 Continuity Test Procedure for Electrical
cal circuits that include one or more electrical contacts in
Connectors
devices such as slip rings, separable connectors, electrome-
chanical relays or closed switch contacts. The user should
3. Terminology
determine applicability for other devices.
3.1 Terms relevant to this guide are defined in Terminology
1.2 The range of techniques described apply to circuit
B 542 except as noted in the following section.
discontinuities (intermittences) of durations ranging from ap-
3.2 Definitions of Terms Specific to This Standard:
proximately 10 nanoseconds to several seconds and of suffi-
3.2.1 intermittence—a transient increase in the voltage
cient magnitude to cause alteration of the circuit function.
drop across a pair of electrical contacts.
Extension of the guide to shorter duration events may be
possible with suitable instrumentation. Events of longer dura-
4. Significance and Use
tion may be monitored by techniques for dc measurements
4.1 This guide suggests techniques to evaluate intermit-
such as those described in Test Methods B 539 or by adaptation
tences in a contact pair while it is subjected to simulated or
of methods described in this guide.
actual environmental stress. Such measurements are a valuable
1.3 The techniques described in this guide apply to electri-
tool in predicting circuit performance under these stress
cal circuits carrying currents typical of signal circuits. Such
conditions and in diagnosing observed problems in circuit
currents are generally less than 100 ma. Extension of these
function under such conditions.
techniques to circuits carrying larger currents may be possible,
4.2 This document is intended to provide some general
but the user should evaluate applicability first.
guidance on the best available practices for detecting, quanti-
1.4 This standard does not purport to address all of the
fying, characterizing and reporting short duration intermit-
safety concerns, if any, associated with its use. It is the
tences in circuits containing electrical contacts. Certain envi-
responsibility of the user of this standard to establish appro-
ronmental stresses such as mechanical shock, vibration or
priate safety and health practices and determine the applica-
temperature change may cause intermittences. These measure-
bility of regulatory limitations prior to use.
ment procedures include methods applicable to contacts oper-
ating under various conditions in testing or in service.
2. Referenced Documents
4.3 Practice B 615 defines methods for measuring electrical
2.1 ASTM Standards:
contact noise in sliding electrical contacts. In contrast Guide
B 539 Test Methods for Measuring Contact Resistance of
2 B 854 provides guidance to the various methods for measuring
Electrical Connections (Static Contacts)
similar phenomena in static contacts.
B 542 Terminology Relating to Electrical Contacts and
Their Use
5. Apparatus
B 615 Practice for Measuring Electrical Contact Noise in
2 5.1 General Comments—The apparatus required varies de-
Sliding Electrical Contacts
pending upon the technique selected and the parameters (such
B 878 Test Method for Nanosecond Event Detection for
2 as duration and magnitude) of the intermittence that the user
Electrical Contacts and Connectors
wants to detect. In general, the cabling must be capable of
This guide is under the jurisdiction of ASTM Committee B-2 on Nonferrous
Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on Available from American National Standards Institute, 11 W. 42nd St., 13th
Electrical Contact Test Methods. Floor, New York, NY 10036.
Current edition approved Oct. 10, 1998. Published January 1999. Available from Electronic Industries Association, 2001 Pennsylvania Ave NW,
Annual Book of ASTM Standards, Vol 02.04. Washington D.C. 20006.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B854–98
TABLE 1 Comparison of Methods of Monitoring Electrical Contact Intermittences
Typical Number
Method Typical Event Characterization Possible Advantages
of Channels
Oscilloscope 1, 2 or 4 DV vs time detailed characterization of each event
Custom Circuitry 1 per circuit Presence or absence of one or more events during a Ability to closely model actual circuit conditions,
preselected monitoring interval, such events defined allows use of various technologies in the transmitting
as above a preselected threshold of DR and duration, and receiving devices
the number of events during the interval may or may
not be recorded.
Event Detector 1 to 64 Presence or absence of one or more events during a Multichannel capability, selection of thresholds for
preselected monitoring interval, such events defined events to be counted
as above a preselected threshold of DR and duration,
but the number of events during the interval is not
recorded.
Bit Error Rate 1 ratio of errors to number of bits transmitted The format of the results is readily applicable to
ranking of interconnection devices with respect to
transmission quality for a specific signal format
carrying signals of the speed to be detected in the study, and that uses this method. Examples of the use of this method are
must be isolated from sources of noise that may cause false shown in the reference by Currence and Rhoades.
indications. 6.3.1 Fig. 1 shows a schematic representation of an
5.2 Special Precautions for Measurements Involving Events
Less than 1 Microsecond in Duration—Detection of events of
duration less than 1 microsecond will require special attention
to the wiring of the detection circuits and instrumentation.
Such attention may include using coaxial cable, shielding the
apparatus from interferences and minimizing cable lengths.
5.3 Specific Apparatus—The apparatus required will vary
depending upon the measurement method selected and the
environmental stresses imposed during the test.
6. Procedure
FIG. 1 Schematic Representation of Oscilloscope Method
6.1 General Comments—The following sections describe,
in general terms, several methods that have been used to detect
example of how this method may be implemented. In selecting
or measure contact intermittences. The user should select an
an oscilloscope, choose a model with response time fast
appropriate method and adapt it as required. Table 1 presents a
enough to observe events of the duration of interest in the
comparison of the attributes of the various methods. The
study. The user may find it convenient to use an oscilloscope
following list covers questions that the user should answer
capable of storing and printing results.
before selecting a test method.
6.4 Custom Circuitry—In this method, the user assembles
6.1.1 What is the definition of an intermittence in the
circuitry to measure the effects of the intermittences under the
intended application? For example, what resistance change
conditions of interest. For example, the circuitry may simulate
over what time interval constitutes an intermittence, or what
the type of source and detector circuitry that the user plans to
error occurs if the contact resistance changes, or what other
design into a system. Alternatively, the user may design
definition is appropriate for the intended purpose of the test
circuitry based on specialized components to achieve capabili-
results?
ties different from those found in commercial instruments. An
6.1.2 Is it necessary to monitor more than one contact
example of custom circuitry was described by Abbott and
simultaneously? If so, is it acceptable to connect the contacts in
Schreiber.
series? If contacts cannot be connected in series, how many
6.4.1 Fig. 2 shows a schematic representation of an example
contacts must be measured simultaneously? of how this method may be implemented. The source and
detector incorporate the specific devices, technology, driver
6.2 Test results should be reported in a format appropriate
for the application and consistent with the format supplied by
the test instrument.
Currence, R. and Rhoades, W., “Predicting, Modeling and Measuring Transient
6.3 Oscilloscope—In this method, an oscilloscope is wired
Resistance Changes o
...
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