This technical specification provides a test method for performing a cyclic (dynamic) mechanical load test in which the module is supported at the design support points and a uniform load normal to the module surface is cycled in alternating negative and positive directions. This test may be utilized to evaluate if components within the module including solar cells, interconnect ribbons and/or electrical bonds within the module are susceptible to breakage or if edge seals are likely to fail due to the mechanical stresses encountered during installation and operation. This test can be performed at any module temperature within the normal operating temperature range. Since the results have been determined to depend on the module temperature during the application of the load it is critical to maintain the module at a constant temperature during the performance of this test.
This technical specification has historically been applied to rigid modules. It cannot be applied to flexible modules unless they are designed to be mounted in a rigid manner. In which case, the cyclic (dynamic) mechanical load test can be applied to the flexible module in its rigid mounting system.
This test has been written as a standalone technical specification, but it is likely to be used in conjunction with other test standards. Typically, this test itself will not result in power loss, but when followed by additional stress tests like thermal cycling and humidity freeze, the damage done by the mechanical cycling results in power loss that would not have occurred due only to the thermal cycling and humidity freeze tests. For example, the transportation testing procedure (IEC 62759) includes the requirements for such a cyclic (dynamic) mechanical load test followed by 50 thermal cycles and 10 humidity freeze cycles.