|
This standard states that the power of the transformers
is calculated according to the following formula:
|
| P(VA)=U (V) X I (A) |
|
Thus, the following table shows the values of the
fuses to be connected to the secondary circuit (output), recommended
for the protection of most popular transformers:
|
| POWER |
SECONDARY
VOLTAGE |
FUSE
|
| VA |
12 -0 - 12 |
24 - 0 - 24 |
55 - 0 - 55 |
110 - 0 - 110 |
Standard |
type |
| 50 |
2 |
1 |
0.4 |
0.2 |
ICE 127 |
CF |
| 100 |
4 |
2 |
0.8 |
0.4 |
|
|
| 150 |
6.3 |
3.15 |
1.25 |
0.63 |
|
|
| 200 |
8 |
4 |
1.6 |
1.25 |
|
|
| 300 |
12 |
6.3 |
2.5 |
1.6 |
|
|
| 400 |
16 |
8 |
3.15 |
2 |
|
|
| 500 |
20 |
10 |
4 |
3.15 |
|
|
| 750 |
32 |
16 |
6.3 |
4 |
|
|
| 1000 |
40 |
20 |
8 |
6 |
|
|
| 1250 |
50 |
25 |
10 |
6 |
|
|
| 1500 |
63 |
32 |
12 |
8 |
|
|
| 2000 |
80 |
40 |
16 |
10 |
|
|
| 2500 |
|
|
20 |
|
|
|
| 3000 |
|
|
25 |
|
|
|
| 3500 |
|
|
|
|
tension>25A |
tension>25A |
| 4000 |
|
|
|
|
IEC 269 |
GL |
| 5000 |
|
|
|
|
|
|
|
| |
|
Protection of the primary circuit. When the transformer
is being connected, an excess current equivalent to approximately
25% In, will be calculated for at least 10 ms. The protection device
is not to be interrupted during this initial working conditions.
Therefore, and as the protection against overload is to be put on
the secondary circuit, the primary one shall be protected against
short-circuit risks only.
|
| |
|
There are two possible type of protection devices:
- aM fuse in compliance with IEC 269
- C.m.c.b. fuse in compliance with IEC 898
|
| |
| The following table shows the protections to be applied for the
primary circuit: |
| POWER |
PRIMARY 220V |
PRIMARY 220V |
PRIMARY 380V |
PRIMARY 380V |
| VA |
Fusible aM |
type C m.c.b. |
Fusible aM |
type C m.c.b. |
| 50 |
1 |
1 |
1 |
1 |
| 100 |
1 |
3 |
1 |
2 |
| 150 |
1 |
6 |
1 |
2 |
| 200 |
1 |
6 |
1 |
3 |
| 300 |
1 |
10 |
2 |
6 |
| 400 |
4 |
10 |
2 |
6 |
| 500 |
6 |
16 |
4 |
10 |
| 750 |
8 |
16 |
4 |
10 |
| 1000 |
10 |
20 |
6 |
16 |
| 1250 |
10 |
25 |
8 |
20 |
| 1500 |
10 |
32 |
10 |
20 |
| 2000 |
12 |
40 |
10 |
25 |
| 2500 |
16 |
40 |
10 |
32 |
| 3000 |
16 |
50 |
12 |
40 |
| 3500 |
20 |
50 |
16 |
40 |
| 4000 |
20 |
63 |
16 |
50 |
| 5000 |
25 |
80 |
20 |
63 |
|
| The aforementioned values are informative
only and are to be used with transformers with an insertion tension
equivalent to 25In |
