Industrial Gearboxes – Designed for Life?

Steve Stratton, Service Specialist, Siemens


Today’s market conditions demand quality and longevity, but this has to be balanced against costs in a very competitive market. How do gearbox manufacturers decide the capacity and size of the gearbox and its components and how long they will last for at a certain market cost. Why are gearboxes much smaller now than they were in days gone by, what has changed to allow this downsizing? What we did in the past to ensure reliability was build it with a very high service factor (this can have an opposite effect though!) and then basically run our equipment to failure. Then we learned about the importance of maintenance but equipment still failed unexpectedly until we discovered the black art of condition monitoring! Of course CM cannot prevent every single failure but combined with good old fashioned maintenance and state of the art design and testing we are in a much better position regarding reliability than we were say 30 years ago. As an OEM we also like to think about the P-F curve or specifically Prior to the P-F curve and what can be done here to gain even higher reliability standards. Good examples of this would be better materials and heat treatment, better bearing designs or treatments, better lubrication, better installation…….the list is endless, but again we have to keep cost in mind. A gearbox could no doubt be built to last forever in theory but we may give our sales people a mammoth task selling it when its 5 X the market price as CAPEX usually takes precedence over OPEX these days!
1. Knowledge of gearbox manufacture and design.
2. What the OEM contributes to reliability of his product.
3. Basic gearbox maintenance and CM to improve its lifecycle.


Time served Mechanical Engineer. 1984 Apprenticeship at Renold Gears UK as a gearbox fitter, stint in the drawing office then Field Service technician. 1991 Moved to Boldypower Transmission company (Uk) as service technician including field service of all power transmission (Multi brand) products. 1995 joined Flender (UK) as part of International field service team, Servicing all industries but mainly steel, cement, Power generation (inc. wind) and railway applications travelling globally. 2005/6 BINDT ISO VA 1&2 certification plus our own CM in-house Certification program in our head office in Germany. By now most work focussed on fast growing wind industry particularly offshore and mostly Condition monitoring tasks. 2012 Moved to Flender (by now part of Siemens) Australia to introduce our CM offering here in the Iron Ore and coal Mines of Australia and to our sales and service teams. 2015 gained VA ISO III with Mobius but then moved into Service Sales Specialist role for all Winergy and Flender products, still retaining a CM and Technical product support function however. Today mostly focused in the wind portfolio as national business development/sales as this market grows rapidly in Australia.