Team 4
FAMU-FSU College of Engineering
Senior Design 2015-2016

SENIOR DESIGN TEAM 4 HAS BEEN TASKED WITH DESIGNING DANFOSS TURBOCOR’S HIGH SPEED MOTOR TEST RIG. A MOTOR-GENERATOR SYSTEM TYPICALLY FEATURES TWO MOTORS THAT ARE COUPLED TOGETHER. ONE MOTOR IS POWERED AND THUS TURNS THE SHAFT ON THE OPPOSING MOTOR. THIS OPPOSING MOTOR IS THE GENERATOR WHICH CAN BE USED TO PRODUCE A VARYING LOAD RESISTANCE FOR THE SYSTEM. THE GENERATOR CAN ALSO BE MONITORED WITH COMPUTERS TO SURVEY THE PRODUCED VOTLAGE FROM BEING BACKDRIVEN BY THE MOTOR. IN OUR SYSTEM, WE ARE REQUIRED TO FEATURE A TORQUE TRANSDUCER, WHICH WILL DETECT THE LIVE TORQUE OUTPUT. THIS TORQUE VALUE CAN THEN BE COMPARED TO A THEORETICAL TORQUE VALUE AT A GIVEN RPM TO EVALUATE A COMPRESSOR'S EFFICIENCY. DANFOSS TURBOCOR IS DIFFERENT FROM OTHER COMPANIES BECAUSE IT USES HIGH SPEED ROTATION (UP TO 40,000 RPM) IN THEIR COMPRESSORS. TO DO SO, THE COMPRESSORS CAN NOT USE REGULAR BEARINGS DUE TO THE HIGH HEAT CAUSED BY FRICTION, THE LOW LIFECYCLE CAUSED BY THE FATIGUE, AND THE MAGNITUDE OF THE STRAINS. TO SOLVE THIS, THE COMPANY USES MAGNETIC BEARINGS, WHICH CREATES A CONTACT FREE ROTATION FOR THE INTERNAL SHAFT. HOWEVER, THESE MAGNETIC BEARINGS CAN ONLY SUPPORT UP TO 200 POUNDS OF RADIAL LOAD UNTIL A SAFETY FEATURE IS TRIPPED, THUS SHUTTING DOWN THE COMPRESSSOR. TO ACHIEVE A THIS TEST RIG, THE TEAM MUST MAKE DEVELOPMENTS WITH RESPECT TO THE SHAFT ALIGNMENT, COUPLINGS, TORQUE TRANSDUCER, AND BASE PLATTFORM . DANFOSS TURBOCOR IS LOOKING FOR A WAY TO TEST THEIR COMPRESSOR MODELS AT VERY HIGH SPEEDS AND MAINTAIN THE SPEED FOR LONGER PERIODS OF TIME.

Foreseen requirements that the motor test rig must meet pertain to the motor-generator shaft alignment, coupler, and torque transducer. Shaft alignment must be done to the best ability of the team. Regardless of the method to align the shafts, it has been identified that with poor alignment, there is a risk of too much radial load on the shaft that may overcome the magnetic bearing forces that keep the shaft spinning true.

Due to unforseen budget constraints, funding for the torque tranducers and laser alignment tool was not approved. To quickly move forward, the team re-planned for a dial indicator alignment method, and removed the integrated transducers from the assembly. This current assembly allows for the alignment method to be tested. If the client wishes to proceed with a torque transducer integration, compressors will be backed away from another to make room for the new rotating assembly.