ASTM B615-79(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:B615–79(Reapproved2006)
Standard Practice for
Measuring Electrical Contact Noise in Sliding Electrical
Contacts
This standard is issued under the fixed designation B615; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope provide sufficient detail for an engineering interpretation of the
noise data and allow the tests to be repeated by another
1.1 This practice describes the practices and factors consid-
laboratory.
ered to be most important in the measurement of electrical
contact noise of sliding contacts.
4. Types of Testing
1.2 This standard does not purport to address all of the
4.1 Type I—Qualification and acceptance testing of electro-
safety concerns, if any, associated with its use. It is the
mechanical devices when low electrical contact noise is
responsibility of the user of this standard to become familiar
important for proper functioning.
with all hazards including those identified in the appropriate
4.1.1 Electrical and mechanical parameters should closely
Material Safety Data Sheet (MSDS) for this product/material
simulate the end use of the device.
as provided by the manufacturer, to establish appropriate
4.1.2 Since the procedure is used as a method of quality
safety and health practices, and determine the applicability of
control, the test parameters must be duplicated each time the
regulatory limitations prior to use.
test is conducted.
2. Terminology 4.2 Type II—Measurement of contact voltage variation as a
method of studying tribological phenomena.
2.1 Definitions:
4.2.1 Tests are designed with specific diagnostic or research
2.1.1 contact noise, n—the varying voltage across a pair of
goals.
electric contacts due to conditions at their interface. It is to be
4.2.2 Electrical and mechanical parameters are based on
distinguished from the variation of signal due to its transmis-
considerations of basic contact physics and not the engineering
sion through electrical conductors (that is, induced voltages
requirements of the device. Selected parameters may be varied
due to adjacent sources). It is also to be distinguished from
as part of the test. For example, rotational rate of a slip ring
acoustic noise which may be generated by the contact action.
may be varied to determine the surface velocity at which
2.1.1.1 Discussion—Stepwise change of resistance of a
hydrodynamic lift becomes important.
wirewound potentiometer due to the definite resistance of a
single turn is not electrical contact noise.
5. Test Conditions
2.1.2 switching or edge noise, n—the electrical contact
5.1 The following test conditions should be controlled or
noise occurring during the period of transition from conduction
known to enable adequate evaluation of test results:
to non-conduction (or vice versa) of a switching device.
5.1.1 Electrical Parameters:
3. Significance and Use 5.1.1.1 Current—Contact current and waveform should be
specified. The limitations of the instrument(s) being used to
3.1 Resistance or voltage values alone do not provide
measure the noise and adequacy of shielding from extraneous
sufficient detail for an engineering evaluation of contact noise.
noise sources must be considered when current level is chosen.
This practice lists the test conditions that should be reported
Type I tests may be made either at current levels chosen to
with noise measurements and indicates some conditions (open
simulate those required in actual use or may be at higher
circuit voltages, currents, etc.) that have been used for quality
current levels in order to enhance test sensitivity provided any
control and research studies. The use of these practices should
such higher current magnitude shall be agreed upon between
the device user and producer (Note 1).
This practice is under the jurisdiction ofASTM Committee B02 on Nonferrous
5.1.1.2 Source Voltage—The maximum open-circuit volt-
Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on
age (to the contacts) and the impedance of the source should be
Electrical Contact Test Methods.
specified. InType I tests, the open-circuit voltage levels chosen
Current edition approved June 1, 2006. Published June 2006. Originally
approved in 1979. Last previous edition approved in 2000 as B615 – 79 (2000).
should simulate those required in actual use and may be at
DOI: 10.1520/B0615-79R06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B615–79 (2006)
more than one level if representative of the end use (Note 1). 5.1.3.1 Temperature of Test—Temperature should be speci-
In Type II tests, any voltage levels may be used depending on fied and held within specific limits.
the objectives of the studies being made (Note 2). 5.1.3.2 Lubrication—Lubrication of the contacts should be
held constant to allow duplication of test. The type, thickness,
NOTE 1—A current of 100 mA from a constant-current (d-c) source
and method of lubricant application requires control.
with a 6-V maximum open-circuit voltage is often used for Type I testing
5.1.3.3 Gaseous Environment—Conditions should be de-
of miniature slip ring-brush units intended for use in inertial guidance
fined as co
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