The Schrage Motor at NIT Calicut has a special place for me..it was the penultimate experiment I did in the Electrical Machines lab of REC. The Electrical Machines lab was a zone of trials and tribulations for any student and an intense learning ground . I think the Electrical Machines Lab of REC is one of the better labs even compared with such facilities among other institutions of its kind. A large area about 1/3rd the area of a Football field housing various kinds of Electrical Machinery. I enjoyed working at this set-up and was a very crucial part of our education honing logical skills and it is probably only in Electrical Engineering a student gets to work with many kinds of machinery with a wide range of Horse Powers.
My success rate at this lab was very very high some times out of fortune and at other times out of fortitude and this lab was always a pointer to me that I had some competence which I used to doubt and was diffident about and with time became certain about. Out of the many experiments I did here I only fumbled once and was successful at all others. It is nice feeling to wire a machine and then switch it on and to note all the meters are reading and the noise it creates and the machine responding to controls.My earliest success in this lab was as a first year student making a staircase wiring in the final exam which I executed to a high degree of accuracy.
The Schrage Motor possibly does not exist in many institutions of this kind I presume and is a special purpose Induction motor. Note the weakness of any Induction Motor is its lack of speed control meaning it works at constant speed..the speed of the rotating magnetic field determined bu 120 f / p which means the rotor speed of the motor can only be controlled by changing the input frequency or changing the number of poles. Before the invention and advent of Power Electronics changing of frequency was an impossible and improbable thought and the only other solution was to wire the system for multiple poles and change the number of poles thereby establishing different levels of speed. Today this motor would look obsolete or in congruent as devices exist that can vary input frequency thereby varying the speed of an Induction Motor.
On being given the Schrage Motor I wired the machine and went about my work to a high degree of proficiency and even did the viva well and as I came out of the lab was filled with a sense of accomplishment that I can deliver under trying circumstance and the Schrage Motor was just one of those trials.