satisfactory to prevent improper operation of the
equipment. Tests should be performed before and after
varnishing in order to ensure reliability of the equipment
and prevent the need for rework as much as possible.
Insulation Test for Grounds
Once coils have been replaced or reconditioned, the
equipment insulation must be tested for proper values.
Insulation tests are made as described earlier with a
megohmmeter (fig. 7-45). Values must be as specified
in table 7-5 to ensure safe operation of the equipment.
High-Potential Test
A high-potential testis made by applying (between
insulated parts) a test potential that is higher than the
rated operating voltage. High potential tests are
frequently used in connection with the repair or
reconditioning of naval equipment ashore.
The purpose of the test (fig. 7-46) is to break down
the insulation if it is weak, thereby indicating defective
material and workmanship, and permitting replacement
Figure 7-45.--Type 1863 Megohmmeter.
before actual use. Since this is designed to break down
Figure 7-46.--AC Dielectric test set.
7-33
