The MTTF-value of 32,1 years, which we sent you in the former mail, is a statistical value (reciprocal of failure rate), which does not need to be reached mandatory in real application (failures because of wear are considered in 'period of validity'). The value is evaluated for 1 x Ie and 1 x Ue aslisted into the attachment "3RW30_ref_MTTF_20-04-2010.pdf" which we already sent by mail yesterday.We have made no other evaluation for different currentand voltage values.All our Soft Starters 3RW30xxx have a life time (Reliability Prognosis)32,1 years. The MTTF / MTTFd ( Mean Time To Failure/Mean Time To Failure dangerous) is definedMean time to a failure or failure to danger. The MTTF can be implemented for components by the analysis of field data or forecasts. With a constant rate of failure, the mean value of the failure-free operation time is MTTF = 1 / Lambda, with Lambda being the rate of failure of the device. (Statistically, it can be assumed that 63.2 % of the affected components failed after expiry of the MTTF.)Our brochure shows up the methods according to IEC 62061 as well as to ISO 13849-1. Safety Integrated Functional Safety of Machines and Systems Convenient Implementation of the European Machinery Directive Link to download of our brochure: http://www.automation.siemens.com/mcms/infocenter/dokumentencenter/ce/Documentsu20Brochures/e20001-a230-m103-v5-7600.pdf

kind regards
LesPaul