CONTROL PANEL (TYPE 4)
SYSTEMS OPERATION
Manual Shutdown
When engine control switch (ACS) is turned to the STOP position or
OFF, RESET position. contacts ( 10 and 11) are open. With contacts
(10 and 11) open, the run relay (RR) de-energizes. In addition, the
STOP position closes contacts (5 and 8). This provides another path to
the shutoff solenoid (SS).
When run relay (RR) is de-energized, contact (RR2) closes and
contact (RR1) opens. With (RR2) closed, it completes a circuit to the
shut-off solenoid (SS). If the STOP position is used, closed contact
(RR2) completes a parallel circuit to shutoff solenoid (SS). (This parallel
circuit is necessary to stop the engine when the engine control switch is
in the AUTO or MAN position.) After the engine stops, (PSW) will open to
de-energize the shutoff solenoid. With contact (RR1) open, the arming
relay (AR) and the dual speed switch (DSS) are de-energized.
Diode D1 helps prevent electrical sparks (arcing) at the contacts in the
shutoff solenoid circuit when the shutoff solenoid is de-energized.
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