Insulator Test Machine for Tensile Test

Insulator tensile testing machine at a glance

• Test performed: mechanical tensile and compression tests, including the tensile test of long rod insulators.
• Test objects: long rod insulators, steel wires, cables, conductors, chains, power fittings, electrical devices, insulating materials and other long specimens.
• Structure: horizontal main machine, which makes assembling and removing long and heavy specimens easy.
• Models: CT-HTT-300, CT-HTT-500, CT-HTT-1000, CT-HTT-2000 and CT-HTT-3000, from 300 kN to 3000 kN maximum load.
• Loading: servo loading system with servo motor and lead screw, testing speed up to 400 mm/min, continuous tests possible with a preset loading programme.
• Accuracy: load measurement better than ±1%, displacement measurement better than ±1%, load resolution 0.05% of full scale.

1. What this machine is used for

This test machine is also known as the long rod insulator tensile testing machine. It performs mechanical tension and compression property tests on all types of steel wires, cables, conductors, chains, power fittings, electrical devices, insulators and insulating materials, and on any other specimen with a long shape.

The main testing machine has a horizontal structure, which makes sample assembling and disassembling easy and gives the specimen the full length it needs. It consists of a main machine, a servo loading system (servo motor and lead screw) and a computer data processing system that analyses the test data and records and prints it. A high precision ratio control valve in the servo loading system tracks and regulates the loading, so the machine can run continuous tests: the user mounts the sample and the machine applies the preset loading programme on its own.

2. Standards applied

The load level, the loading rate and the holding time are taken from the standard that applies to the specimen and from the project specification. Typical references are:

• IEC 61109 – Composite suspension and tension insulators for overhead lines with a nominal voltage above 1000 V, for the mechanical failing load test of long rod composite insulators.
• IEC 60383-1 – Ceramic or glass insulator units for overhead lines above 1000 V.
• IEC 61284 – Overhead lines: requirements and tests for fittings.
• ANSI C29 and DIN insulator standards where the purchaser specifies them.
• GB and ISO test methods for steel wires, cables, conductors and chains.

The machine is used for prototype tests, type tests, routine tests and sample tests, whichever the applicable standard calls for.

3. Technical parameters

Regular models are 300 kN, 500 kN and 1000 kN, which cover all common types of high voltage insulators, from 11 kV disc insulators through 33 kV polymeric insulators to 132 kV and 400 kV suspension insulators of overhead transmission lines. Heavier models up to 3000 kN are available.

Regular valid test lengths are 3 metres, 5 metres and 10 metres. This length is the section length of the tension insulator, not the overall length of the machine, and it can be customized to the client’s requirement.

4. Key functions

• Force testing with automatic tracking of the loading speed.
• Measurement of the loading speed and peak value protection.
• Overloading protection and displacement protection during the test.
• Automatic drawing of the testing force and testing time curve.
• Automatic storage of the test data and printing of the test report.
• Continuous testing with a preset loading programme – the operator only mounts the sample.
• Computer data processing for analysis, storage and printing of the results.

5. Typical applications

• Insulator manufacturers – mechanical property tests and analysis of long rod, disc and pin insulators, for type tests, sample tests and routine tests.
• Testing and research institutions – verification of insulator design and qualification of purchased units.
• Fittings, cable and conductor makers – tensile tests on steel wires, cables, conductors, chains and power fittings.

6. Frequently asked questions

1. What is this machine also called?

It is also known as the long rod insulator tensile testing machine, or the horizontal insulator tensile testing machine, because of its horizontal structure.

2. Why is the machine built horizontally?

The horizontal main machine makes sample assembling and disassembling easy and gives enough tensile space for long specimens such as long rod insulators, conductors and cables.

3. Which voltage levels of overhead line insulators does it cover?

Insulators with voltage levels from 11 kV to 400 kV.

4. What test lengths are available?

Regular types have valid test lengths of 3 metres, 5 metres or 10 metres. This is the section length of the tension insulator, not the overall length of the machine, and it can be customized.

5. What tensile strength do I need?

Regular types have a maximum tensile strength of 300 kN, 500 kN or 1000 kN, which covers all common types of high voltage insulators. Models up to 3000 kN are available for heavier specimens.

6. How do I choose the model – length or strength?

It depends on the insulators you test: different insulators need different test length and different test strength. Choose the length from the longest insulator section and the model from the highest load you have to apply; both can be customized.

Related insulator test equipment

This tensile testing machine belongs to the mechanical test equipment for insulators range. For post and pin insulators Contune supplies the cantilever and torsion testing machine, and for production line routine testing the routine tensile testing machine. See the full insulator testing machines catalogue for further mechanical and electrical test solutions.