Question

- /10P Question 5 The figure shown here is for an inductive pulse tachometer which is used to measure rotational speed based on the frequency of pulses for a given period of time 444444 A. Mention the names of components shown by numerical in their prox- imity (note: number 3Goes not refer to the coil) B. The peak amplitude of the voltage e, is proportional to the rotational speed of the wheel. However, we still do not use it as an indicator of the speed. Briefly mention why 19

Answer 1

The figure given in the problem is of magnetic pick up sensor. Magnetic pick up sensor is used to measure the speed of any rotating system. The name of the components are mentioned below.
And reason behind the fact that although the peak amplitude of voltage in not is dependent on the speed of the wheel but it is not used to determine the speed of the wheel is mentioned below.

Ans (A) Name of the components: (4). Tooth of excitos ring (2). Excitor aing ). Magnetic pick-up sensor. Ans. B): Let us suppose that Speed of Excitor ing And Avesage flue of Magnet (Basically related to strength of magnet) then induced emf : ,L NO sinerN•t) (ed N.p peak Peak could be deter- while the speed -mined by the peak amplitude of voltage as follo w (CO)peak Ki$ But the problem is that the (Magnetic flux), which is the average flur thoough the mognet, reduces

with fime: That as the magnet gets older and older inside means the sensor $ tend to reduce . a rescelt of this the give oYong And may sensor over all value of speed. But the frequency of "cő [ Remember in(amN) ] is only the function of it hence "N" is reljable to determine always more speed from frequency of eo, ather than the C.)peak

Hence due to the ageing effect of magnet with respect to time the peak amplitude of the voltage is not used to determine the speed of the wheel...