Description: Critical speed (nk) is the rotational speed at which acting dynamic forces cause a machine component (e. g. shaft, rotor) to vibrate at its natural frequency (also referred to as intrinsic frequency, fi) and can even result in resonant vibrations throughout the entire machine and pump set; Name: crit. Speed
Description: Speed of rotation at which the frequency of vibration (or its multiples) corresponds to the rotor resonant (lateral or torsional) ; Name: Critical speed
Description: The norm in fixed relation to the feature being described. This defines the parameters that influence the contents of the correlated feature. Type and number of the norm with issue year and issue month must be given, e.g. DIN ISO 4711:YYYY-MM.; Name: Reference norm material, pumping medium