QUESTION $2$: DC MACHINES

$2\mathrm{.}1$ Name THREE applications of a DC series molor.

$2\mathrm{.}2.$ State the function of each of the following relays in a manual faceplate stafter for a DC motor:

$2\mathrm{.}2\mathrm{.}1$ Nowcit relay $($NVR$)$

$2\mathrm{.}22$ Overload ralay $($OLR$)$

$(22)$

$2\mathrm{.}3$ A sx$-$pole, $300$ V $,$ shunt$-$connected machine takes a current of $25$ A$.$from the supply. The armalure is lap$-$wound and has a resistance of $0\mathrm{.}2.$ The shunt feld resistance is $100$ Q and the useful flux per pole is $20$ mWb $.$

Calculate the number of amatiare conductors per slof th the armature has $75$ slots and rotates at $1300$ tmin $.$

$2\mathrm{.}4$ A $400$ V $,$ lourpole, wave wound DC shunt motor has $470$ armature conductors The shunt feld resistance is $150.$

Caledate the torquo devitopert by the molor if the useful flux per pole is $25$ mWr and the motor draws a current of $55$ A from the supply.