AS 3609 pdf download – Insulators—Porcelain stay type— Voltages greater than 1000 V a.c.

AS 3609 pdf download – Insulators—Porcelain stay type— Voltages greater than 1000 V a.c.

AS 3609 pdf download – Insulators—Porcelain stay type— Voltages greater than 1000 V a.c.
Type tests are intended to verify the main characteristics of an insulator which dependmainly on its design. They are carried out once for a new design or manufacturingprocess of insulator and then subsequently repeated only when the design ormanufacturing process is changed;when the change affects only certaincharacteristics,only the test(s) relevant to these characteristics need to be repeated.Type tests are usually carried out on a small number of insulators.
Valid type test certificates are those issued by an independent testing organization,confirming that these tests have been satisfactorily performed. The tests serving forthe establishment of type test certificates may be carried out in a laboratory other thanthat of the issuing organization if a qualified witness of the latter is present.
For mechanical tests, the certificate shall be valid for 10 years from the date of issue.There is no time limit for the validity of certificates for electrical type tests.
Within the above limits,the type test certificates remain valid while there is nosignificant disparity between the results of the type tests and subsequentcorresponding sample tests.
Type tests shall be carried out only on insulators from a lot that has complied with therequirements of the relevant routine tests.
(b)Sample tests
Sample tests are carried out to verify the characteristics of an insulator which canvary within the manufacturing process and the quality of the component materials ofthe insulator. Sample tests are used as acceptance tests on a sample of insulatorstaken at random from a lot that has met the requirements of the relevant routine tests.(c)Routine tests
Routine tests are intended to eliminate defective units and are carried out during themanufacturing process.Routine tests are carried out on every insulator.
1.5 Marking
Each insulator shall be legibly and indelibly marked with the name or trade mark of themanufacturer and the year of manufacture.
Markings shall be printed and shall be applied before glazing.
2.1Verification of dimensions and visual inspection
Checks shall be carried out to verify that the test samples are in accordance with therelevant drawings,particularly in regard to the smooth transition between radii and thetransverse holes and also the longitudinal grooves.
2.2 Power-frequency wet flashover test
2.2.1 Method of assembly
The test sample shall be assembled by threading a l2.6 mm diameter stranded conductorthrough each of the transverse holes of the insulator and each loop shall be secured with aclamp, spaced from the insulator at a distance not less than the length of the insulator. Theloops shall be equal, and the overall length of the assembled test sample when slightlytensioned shall be not less than 10 times the length of the insulator.
2.2.2 Method of support
The assembled test sample shall be strung with its axis at 45° from the vertical with theupper loop attached to a suitable insulator and the lower loop connected to earthed metal.2.2.3Water spray
The direction of the water spray shall be from above, in the vertical plane and normal to theaxis of the assembled test sample.
The water spray shall be reasonably uniform and shall cover the insulator and 150 mm ofthe stranded loops from the edge of the insulator.
The precipitation rate,resistivity and temperature of the water shall be in accordance withthe requirements of AS 1931.1.
2.2.4 Test voliage
While the test sample is being sprayed,a voltage of approximately sine waveform andpower frequency shall be applied between the stranded loops. The insulator shall then beflashed over not less than 10 times.
The r.m.s. flashover voltage to be recorded shall be the mean of not less than 10consecutive observations,measured and corrected in accordance with the requirements ofAS 1931.1.
2.3Mechanical strength test2.3.1 Method of assembly
The test sample shall be assembled by threading a steel wire or steel rope through each ofthe transverse holes and the loops shall be secured with clamps.Both loops shall be equaland the overall length of the assembly shall be not less than 10 times the length of theinsulator.
2.3.2 Test force
A test force shall be applied along the axis of the (looped) assembly and shall be increasedat a steady rate until the specified minimum failing load is reached or fracture occurs.
The type of steel strand or steel rope and the test force shall be recorded.
2.4Porosity test
Fragments from the insulator shall be immersed in a 1 percent solution of fuchsin(l g fuchsin in 100 g methylated spirit) under a pressure of not less than l5 MPa for a timesuch that the product of the test duration in hours and test pressure in megapascals is notless than 180.
The fragments shall then be removed from the solution,washed, dried and again broken forexamination.

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