Section C: Actuator Design $[20$ Marks$]$

Question C$1$

Consider the DC electromagnetic actuator shown in Figure C$1$ which is constructed using Hotrolled Silicon Steel laminations $($see B$\_$H curves on the last page of the exam paper$).$ All dimensions shown are in millimeters. For this actuator $0\mathrm{.}5$ mm diameter Copper wire is used for the winding, the bobbin has a thickness of $5$ mm $,$ the number of turns is $320$ and the current in the coil is $1$ A $.$ At a particular position of the plunger, the length of the air gap is $0\mathrm{.}125$ mm $.$

Figure C$1$