Danfoss Turbocor designs high-efficiency compressors that help heat or cool large buildings. They tasked us with improving their testing procedure for an important stepper motor in their compressors. This stepper motor controls the amount of air entering the compressor by opening and closing small fins, like an air conditioning vent in a house. Danfoss Turbocor tests the stepper motor's lifecycle to assess the motor quality, the reliability of the motor manufacturer, and the overall performance of the compressor. However, they currently lack an official device for this test, so our project focused on building one. Our goal was to design a high-quality stepper motor testing fixture and user interface. This came with multiple requirements. The fixture needed to perform tests for months at a time, requiring reliable materials and electronics. It also needed a user-friendly design. This meant including a simple user interface and visual indicators, like LEDs that show when the motor fails. The fixture even needed to follow Danfoss Turbocor’s safety standards for machines with moving parts. We implemented all the requirements as we developed our design. The result was the H-Frame, designed to securely hold and apply a constant resistance torque to the stepper motor over the lifecycle test. The fixture was made of aluminum and secured together with stainless steel bolts. The user interface consists of a screen and control knob, like those in car displays. With this, the user can start the test, input test parameters such as speed and direction, and review the results after the test finishes. A magnetic sensor tracks rotations and detects motor failure to determine the lifecycle of the motor. Overall, the testing procedure measures the motor’s limits, ensuring that Danfoss Turbocor stepper motors perform as intended.
