External Moment
===============

An external moment acts on a single frame, about a vector with components x, y, and z defined in the reference frame.

**Keyword Arguments**

:param str name: Name given to the moment.

:param str ref_frame_key: Reference frame in which the vector components of the moment are defined.

:param str loaded_frame_key: Frame upon which the moment acts.

:param numeric moment: Moment magnitude.

:param numeric x: X-component of the vector about which the moment is defined.

:param numeric y: Y-component of the vector about which the moment is defined.

:param numeric z: Z-component of the vector about which the moment is defined.