SSC JE Electrical Engineering 2017 Set 2 Paper

At the time of starting, the motor speed is zero so counter emf is also zero. So heavy starting current flow.
$\mathit{E}\propto \mathrm{\varphi }\mathit{w}$
$\mathit{V}=\mathit{E}+{\mathit{I}}_{\mathit{a}}{\mathit{R}}_{\mathit{a}}$
${\mathit{I}}_{\mathit{a}}=\frac{\mathit{V}}{{\mathit{R}}_{\mathit{a}}}$
Starter is use in DC machine to limit the starting current by connecting external resistance series with armature and when back generator the external resistance remove from circuit.