Mechanical And Performance Testing Method Of An Integrated High-Speed Motor Compressor.

Abstract

The integrated electric motocompressor is a recently available technology that has the advantage of drastically simplifying the machine configuration. The use of a high speed electrical motor in the process gas combined with active magnetic bearings eliminates the dry gas seals and replaces the traditional oil bearings and lube oil circuit. In addition, main auxiliaries can be avoided since the motor cooling system uses the compressor process gas as the cooling medium,making the overall package very simple. As this specific arrangement of the machine cannot be tested and validated as a conventional compressor, a validation test must take care of both the compressor and the motor. On the mechanical standpoint, the use of active magnetic bearings (AMBs) has to be considered. It is well known that AMB characteristics differ from oil bearings in terms of damping and stiffness. This paper addresses specific limitation relative to AMBs and mainly nonlinear phenomena like magnetic material or power electronics saturation. The paper also proposes factory acceptance criteria related to this technology. On the performance standpoint, there are no existing guidelines or standards for determining the thermodynamics performance of such systems. This paper describes the testing methodology of an integrated motor compressor to meet the ASME PTC-10 (1997) requirements. Finally the paper will provide guideline for comparing the overall performance of the integrated solution compared to a conventional compressor train.