First-semester students build DC motors
At the end of the lecture "Networks and Circuits I" given by Prof. Christian Franck, the first-semester students had the opportunity to build a simple DC motor. They used the magnetic force on current-carrying conductors, which they had learned about in the lecture. The best projects were measured on 15 December and then awarded prizes during the last lecture of the semester.
During the independent three-week work phase, the students were able to implement their own ideas without guidance. The place and effort of work were freely chosen. In order to earn bonus points for the exam, they had to upload a short video on "Moodle" in which the spinning motor was clearly visible, as well as a PDF with the photo or a sketch of the motor on which they had clearly drawn the magnetic field, the direct current and the resulting direction of force. From the 25 submissions, the nine fastest turning motors were selected for the final round. The prize was to be awarded to the motor that rotated fastest and reached the highest speed in a stable manner without being held down.
Impressions from the high-voltage laboratory and the award ceremony
Prof. Franck reviewing a submission Time for a short exchange
David Wilhelmy built the fastest revolving engine Brian Snider received the special prize for the "cleanest design"
Original constructions
The finalists demonstrated their mini-motors one after the other in the high-voltage laboratory on 15 December. A high-speed camera able to record up to 1 million images per second filmed the rotations and evaluated them.
Besides sophisticated constructions from the 3D printer, there were also very simple prototypes in which, for example, cardboard boxes, pins or PET bottle tops were used. As stated by Prof. Franck in the call for entries, many of the participants had actually been able to create simple yet very stable and fast-running motors using materials worth less than CHF 10. The amount of work required by the finalists was at least five to eight hours and several iterations until the desired final product was completed.
Afterwards, instead of the annual Christmas lecture with exciting experiments in the high-voltage laboratory, the final lecture "Networks and Circuits" was held in a large lecture hall. In compliance with the regulations due to the Corona pandemic, only the finalists were present at the award ceremony in the second part. The rest of the audience followed the proceedings via zoom. In addition to a course certificate signed and presented by Prof. Franck, the winners received original prizes such as a magnetic hourglass, a plasma lighter with a USB charging cable and a glowing light bulb that floats in the air.
One main prize and three special prizes
With a phenomenal performance of 7630 revolutions per minute, David Wilhelmy's motor reached the highest speed. "The most difficult part was integrating the brushes, I had to do a little readjustment there," explains the student from Pfäffikon (ZH). The carbon brushes provide the electrical contact to the rotating part of the machine as a sliding contact. "My axle is a cheap pen," David smiles. "I knew that my motor was fast, but I didn't expect that it would be enough for first place," says the student, who would not actually describe himself as a born hobbyist.
Among all the entries, three special prizes were awarded in addition to the main prize. The prize for the most original project went to Edward He, who had his heart-shaped apparatus whirl around on a Swedish cake. An award for the cleanest design was given to Brian Snider for his elegant construction from the 3D printer with a practical toggle switch. A newly created special award for "special and most powerful motor design", as outside the specifications of the tender rules, was given to Felix Kunz and Jonas Kupferschmid for their brushless DC motor.
In conclusion, Christian Franck thanked all participants for their "extremely creative and diverse" submissions, which had exceeded his expectations many times over. Finally he wished all those present as well as the video-connected course participants a happy and relaxing festive season - before the preparations for the examination session begin.
About the lecture "Networks and Circuits I"
This course introduces the students of the Bachelor's programme "Electrical Engineering and Information Technology" in the first semester to the basics of electrical engineering and electrical and magnetic networks and teaches the basic physical phenomena as well as the required mathematical calculation methods.