There is a simpler scheme to achieve the goal. A proposed approach that defines a mymeter
command taking 2 arguments \#1=name
, \#2=angle
of rotation. Basically it redefines the voltmeter
by drawing a mymeter that has the rotation ability.
\newcommand{\mymeter}[2]
{ % #1 = name , #2 = rotation angle
\begin{scope}[transform shape,rotate=#2]
\draw[thick] (#1)node(){$\mathbf V$} circle (11pt);
\draw[rotate=45,-latex] (#1) +(-17pt,0) --+(17pt,0);
\end{scope}
}

Code
\documentclass[border=1cm,varwidth]{standalone}
\usepackage{tikz,amsmath}
\usepackage[american,siunitx]{circuitikz}
\usetikzlibrary{arrows}
\newcommand{\mymeter}[2]
{ % #1 = name , #2 = rotation angle
\begin{scope}[transform shape,rotate=#2]
\draw[thick] (#1)node(){$\mathbf V$} circle (11pt);
\draw[rotate=45,-latex] (#1) +(-17pt,0) --+(17pt,0);
\end{scope}
}
\begin{document}
OP's circuit:
\medskip
\begin{circuitikz}
\draw
(0,0) to[ammeter] (3,0)
to (4,0)
to[lamp] (4,-2)
to (0,-2)
to[sV] (0,0);
\draw (3,0) to[voltmeter] (3,-2);
\end{circuitikz}
\medskip
Result of proposed approach:
\medskip
\begin{circuitikz}
\draw
(0,0) to[ammeter] (3,0)
to (4,0)
to[lamp] (4,-2)
to (0,-2)
to[sV] (0,0);
\draw (3,0) to[voltmeter,color=white,name=M](3,-2);
\mymeter{M}{0} % try 90, 0, -90
\end{circuitikz}
\end{document}
!
in front of it to turn it into a link. A moderator or another user with edit privileges can then reinsert the!
to turn it into an image again. It is better to turn your code snippet into a (MWE)](meta.tex.stackexchange.com/q/228) starting with\documentclass
ending with\end{document}
and including the necessary packages. This will help who wants to answer you.:)