A $5 \mathrm{~kW}, 220 \mathrm{~V}$ $\text{DC}$ shunt motor has $0.5 \Omega$ armature resistance including brushes. The motor draws a no-load current of $3 \mathrm{~A}$. The field current is constant at $1 \mathrm{~A}$. Assuming that the core and rotational losses are constant and independent of the load, the current (in amperes) drawn by the motor while delivering the rated load, for the best possible efficiency, is _____________ (rounded off to $2$ decimal places).