MA-005 - MINITRANS Installation Manual - Rev 3.1
29-Sep-15
Page 53 of 85
Direct Mount Cradle Vibration Levels
Appendix K
Introduction
K.1
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 a number of 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.
Vibration
K.2
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.
