Atlas Copco QAC 1100 Sd, Инструкция по эксплуатации

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Feeding of leakage current to earth relay
(Optional)
The leakage current to earth relay shall be always fed with
avoltage of 220 V, irrespective of the alternator connection
voltage.
Refer to the parts catalog (ASL) to
d e t e r m i n e t h e c o m p o n e n t s t o b e
replaced in case of a voltage change.
Which are the risks if this change?
1. Short-circuit protection.
If the main circuit breaker is dimensioned for the voltage
and current in the 220-V system, and using the same
components applied in the 380 or 440 V where the system
electric current will be lower, the same operating time will
not be featured.Due to this, in case of a short circuit, the
circuit breaker response time will be longer than necessary
and although this differences is very small (milliseconds)
it may cause the burning of the alternator or its components.
2. AVR calibrations.
Whenperforming the system voltage changes, the voltage
adjustment in the AVR controller shall be performed, and
there may occur the need of adjusting the stability, and
these actions depend on the load applied to the generator;
so there is no adjustment "matrix" to be made on the field
in order to ensure the stability and the reaction to the load
applied to the generator set.During production, the
equipment testing is made on controlled load test benches,
which allow us to perform the calibration and to ensure the
service, with larges precision, the loads dimensioned for
each model.
3. Changing errors.
Such change is subject to assembly errors, such as poor
tightening of cables generating a short circuit or excess of
torque on the busbar breaking the insulatorsor damaging
the AVR circuit board due to an improper operation.