Preventive Maintenance
The proverb 'A stitch in time saves nine' inspired the title of an
Megger Limited booklet on insulation testing, as it neatly sums
up the benefits of preventative maintenance. The savings come
in financial terms from costly repairs, lost production, lost profits
and in human terms, from lives saved in the event of
dangerous electrical faults.
Regular insulation testing of electrical equipment can help to
detect deteriorating insulation. The effects which cause
insulation to deteriorate include mechanical damage, vibration,
excessive heat or cold, dirt, oil, moisture and localized voltage
stresses - all of which can arise on most industrial or utility
equipment.
Insulation tests are sometimes used in isolation as absolute
measures of the quality of the insulation. This is most
appropriate when equipment is being installed and checked for
compliance with a specified 'Pass' level. For operational
equipment the key factors are trends in the insulation readings.
It is therefore important that records of insulation readings are
kept, relating to each piece of equipment or 'Asset' in your
testing regime. Megger supplies test record cards to assist with
such record keeping. There are also a number of influences on
the insulation readings - temperature, humidity and surface
leakage for example and a range of test techniques have been
developed to help with the interpretation of your insulation tests.
Application Notes
M
Equipment
Location
INSULATION TEST RECORD
N
o
Rating
Date Installed
Test Record Example
13