1400W / 1600W should not make much difference - it's just the power of the motor one takes 6 Amps at 230V and the other 7 Amps. The fuse in your plug should be 13 Amps.
The new motor may have just failed - the on/off switch may have failed / there may be a problem with the cable they sometimes get stretched and a wire breaks inside very often at the plug end from heavy tugging.
Vacuum motors often have a thermal cut out safety switch - that may have failed.
So many things to check
Good luck...
Peccavi
March 2010