i got an Problem to get the right position of the 2 Arrows on the right side. I want them to be "in the middle".

[![GSM](https://i.stack.imgur.com/eOwZW.png)](https://i.stack.imgur.com/eOwZW.png)

Code:

```
\documentclass[12pt,a4paper]{scrartcl}
\begin{document}
\usetikzlibrary{decorations.markings}
\usepackage{tikz}
\begin{figure}[htbp]
\centering
\begin{minipage}[b]{.4\linewidth}
    \begin{tikzpicture}
    \node (System) [draw,minimum size=24mm] {Motor};
    \coordinate[above left = of System.west] (a1);
    \coordinate[below = 7mm of a1] (a2);
    \coordinate[below = 7mm of a2] (a3);
    \coordinate[below = 6.5mm of a3] (a4);
    \coordinate[above right= of System.east] (b1);
    \foreach \i [count=\xi from 1] in {2,...,5}
        \coordinate[below=of b\xi] (b\i);
    \foreach \i [count=\xi from 1] in {$u_\mathrm{a}$,$i_\mathrm{a}$,$u_\mathrm{f}$,$i_\mathrm{f}$}
    \draw[-latex'] (a\xi) node[left] {\i} -- (a\xi-| System.west);
    \foreach \i [count=\xi from 1] in {$n$,$M$}
        \draw[-latex'] (System.east |- b\xi) -- (b\xi) node[right] {\i};
    \end{tikzpicture}
    \caption{GSM als Motor}
    \label{fig:gsmmotor}
\end{minipage}
\qquad
\begin{minipage}[b]{.4\linewidth}
    \begin{tikzpicture}
        \node (System) [draw,minimum size=24mm] {Generator};
        \coordinate[above left = of System.west] (a1);
        \coordinate[below = 7mm of a1] (a2);
        \coordinate[below = 7mm of a2] (a3);
        \coordinate[below = 6.5mm of a3] (a4);
        \coordinate[above right= of System.east] (b1);
        \foreach \i [count=\xi from 1] in {2,...,5}
            \coordinate[below=of b\xi] (b\i);
        \foreach \i [count=\xi from 1] in {$n$,$M$,$u_\mathrm{f}$,$i_\mathrm{f}$}
        \draw[-latex'] (a\xi) node[left] {\i} -- (a\xi-| System.west);
        \foreach \i [count=\xi from 1] in {$u_a$,$i_a$}
            \draw[-latex'] (System.east |- b\xi) -- (b\xi) node[right] {\i};
        \end{tikzpicture}
        \caption{GSM als Generator}
        \label{fig:gsmgenerator}
\end{minipage}
\end{figure}
\end{document}

```

how can i center the arrows?

Thanks!