This standard specifies the calibration items and technical requirements, calibration instruments, calibration methods, calibration results and treatment of enameled wire elongation testers. This standard applies to the calibration of enameled wire elongation testers. JB/T 4279.3-1994 Enameled winding wire test equipment calibration method elongation tester JB/T4279.3-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Enameled winding wire test instrument and equipment calibration method elongation tester
1 Subject content and scope of application
JB/T 4279.394
Replaces JB4279.386
This standard specifies the calibration items and technical requirements, calibration instruments, calibration methods, calibration results and processing of enameled wire elongation testers. This standard applies to the calibration of enameled wire elongation testers. 2 Reference standards
JB/T4279.1 General principles for calibration methods of enameled winding wire test instruments 3 Calibration items and technical requirements
3.1 The starting distance Lo between the two clamps should be 200 ± 1mm, and the clamps should be able to clamp the specimen. During the stretching process, the specimen should not slip on one side more than 1mm.
3.2 The movable distance of the movable clamp should be more than 100mm. 3.3 The moving speed of the movable fixture should be 300 ± 60 mm/min. 3.4 When the specimen is broken, the movable fixture of the elongation tester should stop moving automatically, and the digital display value of the elongation (%) should not exceed the actual elongation (%) ± 1 (%). Www.bzxZ.net
4 Calibration instruments
4.1 Stopwatch, graduation value 0.1s.
4.2 Vernier caliper, 300mm, graduation value 0.02mm. 4.3 Blade.
5 Calibration method
5.1 Use a vernier caliper to measure the starting distance Lo of the two fixtures and the movable distance of the movable fixture. 5.2 Use a stopwatch to measure the time t required for the movable fixture to move from the starting position to the end position, and use a vernier caliper to measure the moving distance S. Calculate the stretching speed according to formula (1), take the average of 3 measured values, V=60S/t
Where: S-moving distance of the movable fixture, mm; t stretching time, s.
5.3 Check the fixture performance
5.3.1 Install the specimen with a nominal conductor diameter of 5.0mm, clamp the specimen, and use a blade to mark the distance between the fixtures on the specimen. 5.3.2 Start the elongation tester and perform the tensile test. Use a blade to mark the distance between the fixtures on the specimen after fracture again. 5.3.3 Remove the specimen. Use a vernier caliper to measure the distance between the two knife marks on the two fractured ends of the specimen. 5.3.4 This test allows the largest specification specimen of the instrument unit to be used instead of the nominal diameter of 5.0mm. 5.4 Check the digital display error of elongation
5.4.1 Install the conductor with a nominal diameter of 5.0mm and a 0.02mm sample, and observe whether the movable fixture can automatically stop moving when the sample is broken. This test allows the largest specification sample of the unit to replace the nominal diameter of 5.0mm, and the smallest specification sample to replace the nominal diameter of 0.02mm.
5.4.2 Set the presetter to 10%, 30%, and 50% respectively; start the elongation tester, move the movable fixture to the preset elongation respectively, and record the digital display value 81.
5.4.3 For the extensometer without presetter, install the extensometer on the largest, middle and smallest three specifications of the conductor nominal diameter in the instrument unit, start the extensometer, stretch the specimen until it breaks, and record the digital display value. 5.4.4 Use a vernier caliper to measure the distance L1 of the movable fixture from the starting position when the specimen is broken or reaches the preset elongation, and calculate the actual elongation according to formula (2):
L-Lo×100%
Where; L. The starting distance between the two fixtures, mm; L, the distance between the movable fixture and the fixed fixture after breaking or pulling to the preset elongation, mm. 5.4.5 The digital display error of the secondary elongation shall comply with the requirements of formula (3): 1
Where: Digital display value of elongation, %;
82—actual elongation, %.
Each measurement shall comply with formula (3).
6 Handling of verification results
(3)
6.1 A verification certificate shall be issued to qualified elongation testers, and a verification result notice shall be issued to unqualified ones. The cover forms of the verification certificate and verification result notice are shown in the appendix of JB/T4279.1. 6.2 The verification cycle of enameled wire elongation testers is generally set at 1 year. Additional notes:
This standard was proposed and managed by the Shanghai Cable Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Cable Research Institute of the Ministry of Machinery Industry and others. The main drafter of this standard is Zhu Bing.
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