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3. Over–speed Adjustment – (OS) – Over Frequency
Over–speed protection is provided by a frequency sensing network within the controller. The trip
point of the frequency network is adjustable via a rheostat located on the top of the controller at
the right hand side. Clockwise (CW) rotation increases the trip frequency and, thereby, raises the
shutdown speed.
CRANKING CONTROL
1. Over–crank Protection
This feature provides a preset second crank cycle. Failure of the engine to start by the end of the
crank period results in an ”Over–crank” shutdown and alarm indication.
2. Cranking Disconnect Adjustment (CDS Adjustment)
The cranking disconnect signal is obtained by a frequency network within the controller. The trip
point of the frequency network is not adjustable.
LOSS OF FREQUENCY
Internal protection against loss of frequency input to the cranking disconnect circuit is programmed in
after the unit has started normally. In the event the frequency goes to zero (engine runs out of fuel,
frequency signal source fails, etc.) the LOP shutdown circuit is bypassed and a 12–second wait
period is initiated. If frequency returns within this time period, LOP monitoring resumes and operation
continues normally. If frequency has not returned at the end of this time period, the engine oil
pressure status is observed to determine whether the engine is actually running or stopped. If the
engine has stopped (i.e., air in fuel, etc.), the cranking cycle will begin in an effort to restart the
engine. If the engine has not stopped (loss of input signal, etc.), the unit is shutdown with an
”Over–crank” indication and alarm.
WARNING: Over–crank indication can mean a loss of crank–disconnect signal during the
previous run period. Attempting to restart the engine with no crank–disconnect signal can
destroy the starter motor, which can cause serious personal injury.
This is of particular note since the tendency is to pursue only cranking and start related faults. The
cranking disconnect signal source is a key component in this system and must be checked out
thoroughly whenever an ”Over–crank” shutdown occurs.
NOTE: The controller does not provide protection against loss of signal during start–up. A
shutdown with alarm, due to any of the above conditions, will prevent any subsequent
operation of the generator set. The run–stop–auto selector switch on the control panel
must be momentarily placed in the stop position to reset these functions.
CAUTION: If a dead battery is suspected, remove controller fuse, charge battery (or replace), and
then attempting starting. Damage to engine control may result from jump starting.