I want to calculate starting motor electrical and mechanical quantities (Te, V, I, P, & Q) when using a reduced voltage autotransformer starting? Do you have some references or hand calculations for these?
From this, you can develop the case with your autotransformer lowering the motor voltage at start time, and reducing the voltage dip/flicker on the serving power source. (The only reason I would consider applying a reduced voltage starter on a motor).