Atlas Copco QAS 500

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Qc4002™ MkII module
The Qc4002™ MkII module is located inside the
control panel, and communicates with a display unit,
located in front of the control panel. This control
module will carry out all necessary tasks to control
and protect a generator, regardless of the use of the
generator.
This means that the Qc4002™ MkII module can be
used for several applications.
2.4.2 Output terminal board
The cubicle provides a terminal board for easier
connection of cables. It is situated below the control
and indicator panel.
S2 .......Emergency stop button
Push the button to stop the generator in case
of an emergency. When the button is
pressed, it must be unlocked, by turning it
anti-clockwise, before the generator can be
restarted. The emergency stop button can be
secured in the locked position with the key,
to avoid unauthorized use.
N13 .....Earth leakage relay
Detects and indicates an earth fault current
and activates the main circuit breaker Q1.
The detection level can be set at 30 mA fixed
with instantaneous trip but can also be
adjusted between 30 mA and 250 mA with
time delayed (0 - 1 sec) trip. N13 has to be
reset manually after eliminating the problem
(reset button marked R). It can be overridden
by means of the earth leak switch (S13,
labelled IN) but has to be tested monthly by
pushing test button T13.
S13......Earth relay lock-out switch (N13)
This switch is located inside the cubicle and
is labelled IN.
Position O: No de-energising of the main
circuit breaker Q1 when an earth fault
occurs.
Position 1: De-energising of the main circuit
breaker Q1 when an earth fault occurs.
Q1 .......Main circuit breaker
Interrupts the power supply X1 when a
short-circuit occurs at the load side, or when
the overcurrent (720 A) protection is
activated. When activated, Q1 interrupts the
three phases towards X1. It must be reset
manually after eliminating the problem.
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N13
X6
L1L2
OFF
L1-N
L2L3 L2-N
L3L1
LL LN
L3-N