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 Introduction:
If damage is to be avoided the contact line must be protected
from short-circuits using instant power shut off, which
can be achieved by ultra rapid or amperometric switches that
feed the section involved in the failure .
A short-circuit may bring about a failure current that can assume
values influenced by the distance from the supplier SSE.
The maximum value is important because it will determine the
size of the components used for the plant: in fact it should
be ensured that temperature and electro-mechanical stress, which
arise during short-circuits, are in proportion to the value
and can be supported without damage. Minimum value determines
the current setting at which the ultra-rapid switches will trigger.
As traffic increases and greater power is required by traction
equipment, power ratings have also grown, and have reached and
exceeded the minimum short-circuit trigger levels.
Thus the ASDE device consents protection of the contact line
thanks to the intervention of switches that are safe, rapid
and selective in all working conditions.
How
it Works:
The ASDE2 system envisages connection (mutual slave) of all
bodies charged with supplying and protecting a section by use
of a relating circuit comprising a telephonic couple that usually
carries direct current. Any short-circuit encountered by voltmetric
or amperometric devices on the section brings about the shut
off of current in the relative circuit, determining the permanent
opening of the ultra rapid switches that supply the section
of contact line.
Ultra rapid switches may also be opened by a temporary surge
or by a failure in the ASDE2 system devices.
In such cases, opening will be followed by automatic re-closing
of the switches, preceded by a ground test, with a high predefined
trigger level in the former event and a low level in the latter.
SPECIFICATIONS:
|
Dimensions in mm |
: L 381 H 315 P 150 |
|
Weight in Kg |
: |
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ASDE 2 - 132 Vcc Type |
: Cat. 794/106 |
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ASDE 2 - 110 Vcc Type |
: Cat. __/__ |
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