Test Results and Analytical Predictions for MIL-STD-167 Vibration Testing of a Direct Drive Compressor Supported on Magnetic Bearings

Abstract

External vibration testing was performed on a semihermetic, direct drive compressor on magnetic bearings intended for U.S. Navy Shipboard use. The compressor was placed on a U.S. Navy MIL-STD-167 shaker platform and driven at sinusoidal frequencies from 4 to 33 Hz at graduated displacements equal to a maximum of 1.5 Gs. During the machine design phase, a linear forced response analysis of the coupled rotordynamic system model of the rotor, housing, and magnetic bearings was performed to predict rotorlhousing dis placements and actuator loads. The results were used to guide bearing sizing and control algorithm design. The measured rotor motion and actuator currents correlated well with predictions at all tested frequencies, amplitudes, and orientations. Analysis methodology, test results, and comparisons are reported here.

Investigations on the dynamic behaviour of an on-board rotor-AMB system with touchdown bearing contacts: modelling and experimentation

“…The use of a shock isolator permitted reducing the transmitted axial shock by 65 %, corresponding with the work of Leilei et al [39]: using exible supporting conditions, base disturbance rejection of rotor-AMB system can be improved. Hawkins et al [40] presented an experimental and numerical comparison of a magnetic bearing supported shipboard compressor subjected to sinusoidal translation up to 1.5 G. The vibration requirements were in accordance with MIL-STD-167 standards. AMBs remained in their linear range during these tests.…”