Table C
VOLTAGE/TIME SCHEDULE FOR HIGH VOLTAGE D-C
TESTS OF STATOR INSULATION
Absorption exponent -0.8
All voltage changes with no time delay. Time tabulated are time form start of test to final reading for
respective voltage steps. Voltage is then raised to next step. The times scheduled under column A
are normally used. To save time, the first step may be increased as shown in Columns B, C, and D.
respective voltage steps. Voltage is then raised to next step. The times scheduled under column A
are normally used. To save time, the first step may be increased as shown in Columns B, C, and D.
Dashed line indicates usual test limit for old insulation (5 years or more).
13.8-kV Insulation
6.9-kV Insulation
Minutes from start of test
Minutes from start of test
kV
A B C D kV A B C D
5
10
-
-
-
3
10
-
-
-
9
16-1/2 10
-
-
5
16-1/4
10
-
-
13
21-3/4 10
-
7
21-1/4
15-1/4
10
-
15
25
18-3/4
13-1/2
10
9
25-1/4
19-1/2
14-1/2
10
17
28
21-3/4
16-1/2
13-1/4
10
28-1/4
22-1/4
17-1/4
13
19
30-1/2 24-1/4
19-1/4
16
11
30-3/4
24-3/4
19-3/4
15-1/2
21
33
26-3/4
21-3/4
18-1/2
12
33
27
22
18
22
34-1/2 28-1/4
23-1/4
20-1/4
12-1/2
34-1/2
28-1/8
23-1/2
19-1/2
23
36
29-3/4
24-3/4
21-3/4
13
35-3/4
29-3/4
24-3/4
20-3/4
24
37-1/4 31
26
23-1/4
13-1/2
37
31
26
22
25
38-1/2 32-1/4
27-1/4
24-1/2
14
38-1/4
32-1/4
27-1/4
23-1/4
14-1/2
30-1/2
33-1/2
28-1/2
24-1/2
26
39-3/4 33-1/2
28-1/2
25-3/4
15
40-1/2
34-1/2
29-1/2
25-3/4
27
41
34-3/4
29-3/4
27
28
42-1/4 36
31
28-1/4
29
43-1/4 37
32-1/4
29-1/2
30
44-1/2 38-1/4
33-1/4
30-1/2
4.16-kV Insulation
2.3-kV Insulation
Minutes from start of test
Minutes from start of test
kV
A B C kV A B C
2
10
- -
1
10
-
-
4
47
10
-
2
17
10
-
6
22-1/2
15-3/4
10
3
22-1/2
15-3/4
10
7
26
19-1/4
13-3/4
3-1/2
26
19-1/4
13-3/4
8
29
22-1/4
16-3/4
4
29
22-1/4
16-3/4
8-1/2
30-3/4
24-1/4
18-3/4
4-1/4
20-3/4
24-1/4
18-3/4
9
32-1/2
26
20-1/2
4-1/2
32-1/2
26
20-1/2
9-1/2
34-1/4
27-1/2
20-1/2
4-3/4
34-1/4
27-1/2
22-1/4
10
35-3/4
29
23-3/4
5
35-3/4
29
23-3/4
10-1/2
37-1/4
30-1/2
25-1/4
5-1/4
37-1/4
30-1/2
25-1/4
11
38-3/4
32
26-3/4
5-1/2
38-3/4
32
26-3/4
11-1/2
40
33-1/4
28
5-3/4
40
33-1/4
28
12
41-1/4
34-1/4
29-1/4
6
41-1/4
34-1/2
29-1/4
30