Table A
MAXIMUM D-C TEST VOLTAGES FOR MACHINES
A-c voltage rating
Old insulation
New insulation*
of winding
over 5 years old
less than 5 years old
(kilovolts)
(kilovolts)
(kilovolts)
100% 85%
1/
2.3 - 2.5
5
4.25
6
4.16
10
8.5
12
6.9 - 7.2
15
12.75
20
11 - 13.8
20 - 25 17 - 21.25
30
1/
Normal limit for ramp testing. See paragraph 42 for more information on maximum test voltages for
machines.
* Any winding showing visible signs of deterioration should be considered old insulation for test
purposes regardless of age.
27 (FIST 3-1 12/91)