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Qualification shock testing has been completed for a new chilled water plant developed for the US Navy. The variable speed compressor at the heart of the chiller system includes a direct drive, high-speed permanent magnet (PM) motor, PM bias active magnetic bearings, and a backup bearing system. For MIL-S-901D shock certification, the chiller was mounted on a Navy floating shock platform (barge) and subjected to a standard sequence of four different shock impacts generated from high explosive charges from varying angles and standoff distances. The chiller was fully operational during three blasts and in standby mode for the fourth blast. In the standby mode, the shaft is de levitated and stationary on the backup bearings and the chiller secured. The backup bearing system of the motor absorbed the response to the shock impacts and the magnetic bearings subsequently recovered levitation as designed. The shock testing was simulated using a transient, nonlinear rotordynamic analysis including the magnetic bearing control and saturation features, backup bearings with resilient mounts and associated clearances, and structural dynamic models of the rotor and housing. Compressor/motor housing acceleration measured during the testing was used as the driving input into the simulation. Some rotor position data recorded during shock testing, the simulation approach and comparisons are reported and discussed.

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.

External vibration testing was performed on a semi-hermetic, direct drive compressor on magnetic bearings intended for US Navy Shipboard use. The compressor was placed on a US Navy MIL-STD-167 shaker platform and driven at sinusoidal frequencies from 4 to 33 Hz at graduated displacements equal to a maximum of 1.5Gs. 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 rotor/housing displacements 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.

No abstract