IEEE 116-1975 pdf free.IEEE Standard Test Procedure for Carbon Brushes.
It is the purpose of this standard to providea procedure for determining certain operatingcharacteristics of carbon，carbon-graphite,electrographite, graphite, and metalgraphitebrushes under prescribed test conditions forall types of rotating ac and dc motors and similar apparatus.The operating characteristicscovered in this standard are: voltage drop,coefficient of friction, wear ratio as affected bylow humidity, and commutating ability.
IEEE 116 for properties of materi-als and properties of shunt connections are defined in ANSI C64.1-1970，Brushes for Electrical Machines (NEMA CB1-1970).Dimen-sions,tolerances，and descriptive terminologyof brushes for test procedures should conformto ANSI C64.1-1970.
Quantities expressed in parentheses are inthe International System of Units (commonlycalled SI units).Brush performance is influenced by operating and ambient conditions such as springpressure, current density, brushface to collec-tor-surface contact, surface film, absolute humidity，ambient temperature,atmospheres,collector material，etc. Because of the manyvariables involved. it is impractical to estab-lish specific values of performance character-istics or to expect reproducible values underdiffering application conditions.Since manyof the factors involved in testing brushes arenot easily controllable (with precision),andsince the performance characteristics mayvary significantly, the test procedures definedwill not give entirely consistent results. Tominimize inconsistencies，conditions of testing must be carefully controlled. Brush char-acteristics are commonly expressed in terms of( 1) a measured range of values.(2) minimumor maximum measured values, or (3) relativevalues which can be classified by words suchas “high,”low,””medium,” etc.Tests for coefficient of friction and voltagedrop and the effect of humidity are made onthe same equipment with the same test brush-es. In many cases it will be convenient tomake the test simultaneously.
The standard test ring is made of elec-trolytic copper with a minimum of 99.90 per-cent purity and has a diameter of 10 in (254mm) and a width of 3 in (76.2 mm). It shallhave 128 evenly spaced axial slots on the sur-face, each slot being 0.030 in (0.76 mm) wide.The test ring shall be mounted on 2 ball bear-ing pedestals on a heavy base.
When data is required on ring material oth-er than copper, a substitution for copper maybe made. For slip ring investigations,the axialslots may be omitted. Brushes of opposite po-larities should be run in different tracks.Where test conditions differ from this proce-dure,the results should be fully annotatedwith test conditions.The assembly shall be driven by a 1 – 2 hpadjustable speed dc motor through a flexiblecoupling to obtain a steady ring surface speedup to 6000 ft/min (30.5 m/s).A surface speed of5000 ft/min (25 m/s) is used for the standardtests. Other speeds may be used for specialtests.IEEE 116 pdf download.