Answer sTEm-at-Work Puzzle #49: Wind Turbine final Quality Assurance Test


Analysis
This puzzle returns to the sine wave as a visual tool.  The idea of lead/lag is difficult of many students.  The situation presented in this puzzle states what is expected of the signals.  The puzzle answer in the annotated puzzle graphic below emphasizes the leading characteristics of the current signal when it is compared to the voltage signal.  If the sine and cosine functions are also being (or have been) taught the phase shift can be introduced as well.  Once that idea is accepted, students can start to draw phasor diagrams as a quick alternative way to visualize if a signal is leading or lagging.  (The angle between the two phasors is the phase angle produced by the phase shift.)  There are web access routines for learning about and drawing phasor diagrams.  An oscilloscope simulator may also be available from the web.  If so, the shift from two signals in phase to two signals out of phase will finish off this lesson idea.  Since most of the intellectual ideas in this puzzle are visually driven, students from middle school can learn the fundamental idea presented.     

Question
The technician has the wind turbine shipped to the customer. (Yes   or   No)

Answer: YES