  Contractions (and graded contractions) of Lie algebra, Lie bialgebra and Hopf
algebra are discussed. It is noticed the fundamental role of E.In{\"o}n{\"u}
and E.P.Wigner idea of degenerate transformations. A constructive algorithm for
description of contractions of quantum Cayley-Klein algebras $ so_{z}(n+1; {\bf
j}) $ with different choice of the set of primitive operators is suggested. For
nonsemisimple quantum algebras it gives nonisomorphic Hopf algebras. From
physical point of view this algorithm gives the different physical
interpretations of primitive operators for mathematically the same
nonsemisimple quantum algebra. The case of $ so_{z}(3; {\bf j}) $ is regarded
in detail.
