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autotransformers single three phase Brioschi electric transformers
transflormers
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over-temperature
 


PARTS OVER-TEMP.�C
Windings (reels and cores in contact with them), when insulated with:  
*material of class A (1) 75
*material of class E (1) 90
*material of class B (1) 95
*material of class F (1) 115
*material of class H(1) 140
*other materials (2)
exterior cases of fixed transformers (3)
exterior cases, handles and similar parts of mobile transformers (3)
---
60

if these parts are continuously held in hand during normal use:
*metal
*other materials

30
50
If these parts are not held in hand during normal use:
*metal
*other materials


35
60

1) The material classification is in compliance with IEC 85 publication.
2) In case of using materials different from the ones indicated in the IEC 85 publication, under the A, E, B, F and H names, the materials used must comply with the tests mentioned in 13.3.
3) If any element is a part of the transformer external surface, the over-temperature of that element must not exceed the established temperature of its external housing.
4) Table referring to ambient temperature of 25°C.


POWER TAKEN ACCORDING TO THE AMBIENT TEMPERATURE
Ambient temperature 40 45 50 55 60 65
Obtainable power (%) 100 90 80 72 66 62


POWER OBTAINABLE ACCORDING TO ALTITUDE
Altitude (mt) 1000 1500 2000 3000 4000 5000
Taken power (%) 100 97,5 95 90 85 80


TEST VOLTAGES Work voltage not exceeding:
TEST VOLTAGE APPLICATION POINTS <50 150 250 440 690 1000
a) Between live parts of primary and secondary circuits. (This rule is not applied to circuits separated by an earthed metal shield). 500 2000 3500 4200 5000 5500
b) Through the basic or supplementary insulation among:
* the live parts which are or could become of different polarities.
* the live parts under tension and earth, if it (earth) is meant to be connected to the protection conductor.
* the accessible metallic parts and a metal bar with the same diameter as the flexible cable fitted into the input pipes, bushes, anchor devices and similar.
250 1000 1750 2100 2500 2750
c) Through a reinforced insulation, between the earth and the live parts under tension. 500 2000 3500 4200 5000 5500