DSH 391C Ball pressure test
http://decisions.iecee.org/icons/ecblank.gif DSH 391C
Ball pressure test
4, 7, 9, Figure 2
60695-10-2(ed.2)
Standard-
IEC 60695-10-2:2003, Ed.2
Subclause(s):
4
7
9
Figure 2
No. Year
DSH
0391C 2010
Category:
VARIOUS, GENERAL
Developed by:
CTL-WG2 + WG4
Subject:
Ball pressure test
Key words:
-Diameter of indentation
-Pressure Ball
-Test Specimen Support
Approved at the 48th CTL
Plenary Meeting, year
2011.
Replaces DSH 391 and
DSH 391mod.
Question:
Define the “best practice” test procedure for the ball pressure test based on the
requirements of the standard, and for practical reasons also based on 89/1011/CD, which
is not in all respects identical with the requirements of the standard.
Decision:
In addition to clause 4.1 of the standard and due to various qualities of steel balls for rolling
bearings, the tolerance for the steel ball diameter shall not exceed ±1% to ensure
comparable results.
In addition to clause 4.2 of the standard, the specimen support shall be a metal block of
steel, with a diameter 50 mm and a height of 100 mm or equivalent volume and mass.
In addition to 4.3 of the standard, a forced air convection single cabinet according to IEC
60216-4-1:1990, clauses 4.1.5 and 4.1.6 shall be used.
In addition to 7.1 of the standard conduct the test in air, in a heating cabinet being capable to
return within 5 min and without any temperature overshoot exceeding +5°C to the
previously adjusted and required air temperature within a tolerance of +/- 2°C .
Measure the air temperature as close as possible to the test specimen.
Before introducing the test specimen, bring the cabinet, the test apparatus and the test
specimen support to the required temperature and maintain the required test temperature for
24 h or until equilibrium conditions are reached, whichever occurs sooner.
When thermal equilibrium conditions are reached, place the test specimen on the approximate
centre of the test specimen support so that its upper surface is horizontal. Gently lower the
pressure ball on to the approximate centre of the test specimen. Ensure that no conditions exist
that will cause the pressure ball to move other than in a downward direction during the test.
After the ball pressure apparatus has been applied for 60 +2/-0 minutes, remove it and within 10
s immerse the test specimen in ambient temperature water for 6 min ±2 min.
Within 3 minutes of removal from the water, measure the diameter of the indentation caused by
the pressure ball to one decimal place.
Deviant from 7.2 of the standard, but in accordance with 89/1011/CD, the diameter “d” of
the indentation is to be measured as close as possible to the diameter of the “solid edge”
of the indentation according to both a) figure 2a shown below and b) picture examples
given in Annex A. The diameter of the solid edge of the indentation (dimension d ) shall
exclude any material deformation as shown in figure 2c below.
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