Appendix K Direct Mount Cradle Vibration Levels - GE Kelman Minitrans Installation Manual

K.1 Introduction
K.1.1 Purpose and scope
The purpose of this appendix is to give guidance as to when the 'GE Direct Mount Cradle'
should be used to directly mount the product to a transformer. This guidance is based on
the study of the:
▪
Vibration levels exhibited by several transformers and reactors worldwide.
▪
Performance of the product under environments of varying vibration levels with and
without the 'GE Direct Mount Cradle'.
This document does not attempt to give guidance on how to install the 'GE Direct Mount
Cradle'. For this information, see Appendix L.
K.2 Vibration
K.2.1 Transformer vibration frequencies
The main vibration frequencies of a transformer are those produced by
magnetostriction. These are:
▪
multiples of 100 Hz in a 50 Hz region.
▪
multiples of 120 Hz in a 60 Hz region.
There may also be lower levels of vibration present at 50 Hz and 60 Hz.
K.2.2 Limits of vibration
Figure K-1 overleaf illustrates the vibration limits for the product with and without the
GE Direct Mount Cradle. This data outlines the vibratory thresholds to support when the
use of a cradle is appropriate.
MA-005 - Minitrans Installation Manual - Rev 4.5
Appendix K Direct Mount Cradle Vibration Levels
13-Aug-20 Page 52 of 86