Thermal-Mechanical Stress Test Machine for Composite and Porcelain Insulators

Technical Specifications

Key Features

• Simultaneous mechanical load and temperature cycling — tests real service conditions
• Walk-in environmental chamber with internal LED lighting
• Multi-zone temperature control for uniformity across long specimens
• Programmable multi-step profiles for complex test sequences
• Continuous data logging of load, temperature, displacement and leakage current

Thermal-Mechanical Testing per IEC 61109

IEC 61109 requires composite insulators to undergo thermal-mechanical testing as a sample test. The insulator is subjected to a 96-hour cycle: 24 hours at -25 plus or minus 5 deg C then 24 hours at +40 plus or minus 5 deg C, repeated, while under a specified mechanical load (typically 50% of SML). This verifies that differential thermal expansion between core rod, housing, and end fittings does not cause mechanical degradation.

Importance for Porcelain Insulators

For porcelain insulators per IEC 60383, thermal-mechanical testing verifies that the cement joint between porcelain body and metal cap/pin maintains integrity through temperature cycles. Thermal expansion mismatch between porcelain, cement, and metal can cause micro-cracking and eventual mechanical failure if not properly designed.