Abstract: Temperature value determination of at least one variable frequency drive component is provided. In one form, a method includes providing a variable frequency drive that includes a first component in thermal communication with a second component in thermal communication with a switching device. A temperature value of the second component is determined using a temperature value of the first component, a power loss characteristic of the drive, and a first characteristic of heat transfer between the first and second components. The method further includes sensing a temperature value of the second component and determining a temperature value for the switching device using the power loss characteristic, a second characteristic of heat transfer between the second component and the switching device, and the greater of the sensed and determined temperature values of the second component. Further embodiments, forms, features, and aspects shall become apparent from the description and drawings.

Abstract: Systems and methods are used to control operation of a rotary compressor of a refrigeration system to limit or prevent movement of rotors due to axial thrust loading resulting from rapid changes in speed of the rotors of the compressor. The operational profile of the motor is controlled to maintain acceleration torque and deceleration torque within predefined limits. The acceleration torque and deceleration torque are maintained within the predefined limits by controlling the speed of the motor, or by controlling the torque applied by the motor to the rotors during acceleration or deceleration.

Abstract: The invention is a rapid prototype apparatus having a removable build chamber and a plurality of alignments surfaces that can be used to properly align the build chamber with the process chamber with minimal adjustments by a user. In one embodiment, the apparatus comprises a process chamber attached to a support housing and a build chamber that is removably attached to the support housing. The build chamber may be inserted into the support housing and is moveable between a load position and a build position. The build chamber includes a moveable build platform and a plurality of alignment surfaces that are each adapted to releasably engage a corresponding surface on the support housing. As the build chamber moves into the build position, the alignment surfaces align the build platform the process chamber. As a result, the apparatus may be used to accurately align the build chamber with the process chamber.