Large flameproof cage induction motors for exceptional ambient temperatures

The need to build a motor enclosure which is capable of withstanding the overpressure from an internal explosion, without igniting any surrounding flammable gas, inevitably results in a heavier machine. Weight is often at a premium, particularly in offshore applications. There may also be a perceived cost disadvantage due to the fact that not all motor manufacturers can offer EExd certified equipment at outputs in excess of 1 MW. The development of a new and cost effective range of flameproof cage induction motors required a radical review of cooling methods and resulted in an effective thermal solution. This led to other potential problems due to the effects of pressure piling under explosion conditions which became more significant as the ambient temperatures were lowered. The use of new CFD software has possible benefits in predicting the effects of ignition in a rotating complex structure