{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/33452"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/33452","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Thermal Overload Capabilities of an Electric Motor and Inverter Unit Through Modeling Validated by Testing","abstract":"VPT, Inc and the U.S. Dept. of Energy have sponsored the development of a high-speed 12 kW AC induction motor to drive automotive fuel cell air compressors. As one part of the development, thermal considerations and the cooling system are detailed in this paper. The motor and inverter are packaged in one unit with the heat sink in the middle. The heat sink is a cold chamber designed to absorb the maximum heat losses from the unit. Empirical data was used to validate the model of the cold chamber and finalize the design. A lumped capacitance finite-difference model was developed to simulate the entire motor inverter assembly. The individual components of the thermal model were tested and the data was used to calibrate and validate the thermal model. Using the model, the thermal overload conditions were investigated. The limiting factors are the stator copper winding temperatures, which can damage the plastic slot liners. The double current test was simulated and operating temperatures of the system remained within thermal limits for 4 minutes. As a conclusion from the model, the thermal resistances from the stator to the case or the heat sink need to be reduced. Integrating the motor casing and end plate to the heat sink, rather than building it in sections, would reduce the thermal contact resistances. Also the copper winding ends in the stator could be coated in material that would bond to the case, thus increasing heat transfer from the windings to the case.","abstract_html":"VPT, Inc and the U.S. Dept. of Energy have sponsored the development of a high-speed 12 kW AC induction motor to drive automotive fuel cell air compressors. As one part of the development, thermal considerations and the cooling system are detailed in this paper. The motor and inverter are packaged in one unit with the heat sink in the middle. The heat sink is a cold chamber designed to absorb the maximum heat losses from the unit. Empirical data was used to validate the model of the cold chamber and finalize the design. A lumped capacitance finite-difference model was developed to simulate the entire motor inverter assembly. The individual components of the thermal model were tested and the data was used to calibrate and validate the thermal model. Using the model, the thermal overload conditions were investigated. The limiting factors are the stator copper winding temperatures, which can damage the plastic slot liners. The double current test was simulated and operating temperatures of the system remained within thermal limits for 4 minutes. As a conclusion from the model, the thermal resistances from the stator to the case or the heat sink need to be reduced. Integrating the motor casing and end plate to the heat sink, rather than building it in sections, would reduce the thermal contact resistances. Also the copper winding ends in the stator could be coated in material that would bond to the case, thus increasing heat transfer from the windings to the case.","abstract_has_math":false,"creators":["Lohse-Busch, Henning"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Nelson, Douglas J."],"committee_members":["Ellis, Michael W.","Reinholtz, Charles F."],"year":2004,"date_issued":"2004-05-28","date_published":"2004-05-28","updated_at":"2026-07-22T22:19:18Z","subjects":["Integrated AC induction motor-inverter unit","Finit"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06062004-150827"],"render_values":[{"text":"etd-06062004-150827","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/33452","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Nelson, Douglas J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Ellis, Michael W.","Reinholtz, Charles F."]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Lohse-Busch, Henning"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:39:30Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:39:30Z","2004-06-30"]},{"key":"dc:date.issued","label":"Date","values":["2004-05-28"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Integrated AC induction motor-inverter unit","Finit"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-06062004-150827"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/33452"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["VPT, Inc and the U.S. Dept. of Energy have sponsored the development of a high-speed 12 kW AC induction motor to drive automotive fuel cell air compressors. As one part of the development, thermal considerations and the cooling system are detailed in this paper. The motor and inverter are packaged in one unit with the heat sink in the middle. The heat sink is a cold chamber designed to absorb the maximum heat losses from the unit. Empirical data was used to validate the model of the cold chamber and finalize the design. A lumped capacitance finite-difference model was developed to simulate the entire motor inverter assembly. The individual components of the thermal model were tested and the data was used to calibrate and validate the thermal model. Using the model, the thermal overload conditions were investigated. The limiting factors are the stator copper winding temperatures, which can damage the plastic slot liners. The double current test was simulated and operating temperatures of the system remained within thermal limits for 4 minutes. As a conclusion from the model, the thermal resistances from the stator to the case or the heat sink need to be reduced. Integrating the motor casing and end plate to the heat sink, rather than building it in sections, would reduce the thermal contact resistances. Also the copper winding ends in the stator could be coated in material that would bond to the case, thus increasing heat transfer from the windings to the case."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Thermal Overload Capabilities of an Electric Motor and Inverter Unit Through Modeling Validated by Testing"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Nelson, Douglas J."],"dc:contributor.committeemember":["Ellis, Michael W.","Reinholtz, Charles F."],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Lohse-Busch, Henning"],"dc:date.accessioned":["2014-03-14T20:39:30Z"],"dc:date.available":["2014-03-14T20:39:30Z","2004-06-30"],"dc:date.issued":["2004-05-28"],"dc:description.abstract":["VPT, Inc and the U.S. Dept. of Energy have sponsored the development of a high-speed 12 kW AC induction motor to drive automotive fuel cell air compressors. As one part of the development, thermal considerations and the cooling system are detailed in this paper. The motor and inverter are packaged in one unit with the heat sink in the middle. The heat sink is a cold chamber designed to absorb the maximum heat losses from the unit. Empirical data was used to validate the model of the cold chamber and finalize the design. A lumped capacitance finite-difference model was developed to simulate the entire motor inverter assembly. The individual components of the thermal model were tested and the data was used to calibrate and validate the thermal model. Using the model, the thermal overload conditions were investigated. The limiting factors are the stator copper winding temperatures, which can damage the plastic slot liners. The double current test was simulated and operating temperatures of the system remained within thermal limits for 4 minutes. As a conclusion from the model, the thermal resistances from the stator to the case or the heat sink need to be reduced. Integrating the motor casing and end plate to the heat sink, rather than building it in sections, would reduce the thermal contact resistances. Also the copper winding ends in the stator could be coated in material that would bond to the case, thus increasing heat transfer from the windings to the case."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-06062004-150827"],"dc:identifier.uri":["http://hdl.handle.net/10919/33452"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Integrated AC induction motor-inverter unit","Finit"],"dc:title":["Thermal Overload Capabilities of an Electric Motor and Inverter Unit Through Modeling Validated by Testing"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:18Z"}