ASTM B615-79(2000)
(Practice)Standard Practice for Measuring Electrical Contact Noise in Sliding Electrical Contacts
Standard Practice for Measuring Electrical Contact Noise in Sliding Electrical Contacts
SCOPE
1.1 This practice describes the practices and factors considered to be most important in the measurement of electrical contact noise of sliding contacts.
1.2 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 615–79(Reapproved 2000)
Standard Practice for
Measuring Electrical Contact Noise in Sliding Electrical
Contacts
This standard is issued under the fixed designation B 615; 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 4. Types of Testing
1.1 This practice describes the practices and factors consid- 4.1 Type I—Qualification and acceptance testing of electro-
ered to be most important in the measurement of electrical mechanical devices when low electrical contact noise is
contact noise of sliding contacts. important for proper functioning.
1.2 This standard does not purport to address all of the 4.1.1 Electrical and mechanical parameters should closely
safety concerns, if any, associated with its use. It is the simulate the end use of the device.
responsibility of the user of this standard to establish appro- 4.1.2 Since the procedure is used as a method of quality
priate safety and health practices and determine the applica- control, the test parameters must be duplicated each time the
bility of regulatory limitations prior to use. test is conducted.
4.2 Type II—Measurement of contact voltage variation as a
2. Terminology
method of studying tribological phenomena.
2.1 Definitions: 4.2.1 Tests are designed with specific diagnostic or research
2.1.1 contact noise—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
5. Test Conditions
single turn is not electrical contact noise.
2.1.2 switching or edge noise—the electrical contact noise 5.1 The following test conditions should be controlled or
occurring during the period of transition from conduction to known to enable adequate evaluation of test results:
non-conduction (or vice versa) of a switching device. 5.1.1 Electrical Parameters:
5.1.1.1 Current—Contact current and waveform should be
3. Significance and Use
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
provide sufficient detail for an engineering interpretation of the
the device user and producer (Note 1).
noise data and allow the tests to be repeated by another 5.1.1.2 Source Voltage—The maximum open-circuit volt-
laboratory.
age (to the contacts) and the impedance of the source should be
specified. InType I tests, the open-circuit voltage levels chosen
should simulate those required in actual use and may be at
This test method is under the jurisdiction of ASTM Committee B02 on
more than one level if representative of the end use (Note 1).
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
In Type II tests, any voltage levels may be used depending on
B02.11 on Electrical Contact Test Methods.
Current edition approved June 29, 1979. Published September 1979. Originally the objectives of the studies being made (Note 2).
published as B 615 – 76. Last previous edition B 615 – 76.
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B 615
NOTE 1—A current of 100 mA from a constant-current (d-c) source
5.1.3.2 Lubrication—Lubrication of the contacts should be
with a 6-V maximum open-circuit voltage is often used for Type I testing
held constant to allow duplication of test. The type, thickness,
of miniature slip ring-brush units intended for use in inertial guidance
and method of lubricant application requires control.
systems.
5.1.3.3 Gaseous Environment—Conditions should be de-
NOTE 2—InType II tests, one must consider the softening, melting, and
fined as completely as possible.At least a designation such as“
arc-sustaining voltages of the contacts being tested. Also, if it
...
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