Alpha Technologies AlphaGen PN-6x-T 7.5kW 48VDC - Technical Manual - Manual (Page 60)

60 042-288-B0-001, Rev. A
4.0 The Engine Control Module, continued
4.5 Alarm Classifi cations
Major Alarms:
A major alarm indicates a critical failure or situation that causes the system to go off-line.
Major alarms cause the engine to shutdown immediately and generally prevent further
operation. Most major alarms are latched by the ECM. Placing the RAS switch to the STOP
position for three seconds, then switching back to AUTO clears any latched alarms and
starts the generator (if the cause of the alarm has been corrected). A site check by service
personnel is required to repair the fault and clear the system.
• Low Oil Pressure (Latching): Engine oil pressure is below safe limits. APU operation is
suspended. The alarm is cleared when the Reset command is issued or when the manual
stop switch is activated.
• Engine Over-temp (Non-latching): Engine temperature has exceeded safe limits. APU
operation is suspended. The alarm is reset when the engine temperature falls within safe
limits.
• Engine Over-speed (Latching): Engine rpm has exceeded safe limits. APU operation is
suspended. The alarm is cleared when the Reset command is issued or when the manual
stop switch is activated.
• Engine Over-crank (Latching): Engine failed to start. The alarm is cleared when the
Reset command is issued or when the manual stop switch is activated.
• Alternator Over-voltage (Latching): The generator set has detected the alternator
output voltage is too high. Depending on generator type, this likely means that the
voltage regulator or engine speed governor has failed. Operation of the unit has been
suspended. The alarm is cleared when the Reset command is issued or when the manual
stop switch is activated.
The alternator over-voltage alarm can be triggered in three ways:
1.) The generator controller can signal the ECM that an over-voltage condition exists.
2.) A programmable threshold of 57V (Hi DC Bus Level) is exceeded for fi ve seconds
(programmable for a range of 5-15 seconds; fi ve seconds is the default value).
3.) A fi xed threshold of 2.5V/cell (60V for a 48V system) is exceeded for fi ve seconds.
• Gas Hazard (Latching): The concentration of hydrocarbon fuel in the power system’s
enclosure air space has exceeded safe limits or 10%-20% of the Lower Explosive
Limit (LEL) for more than three (3) seconds. APU operation is suspended. The alarm is
cleared when the Reset command is issued or when the manual stop switch is activated.
• Water Intrusion (Non-latching): Water level within the main or fuel enclosure has
exceeded safe limits. APU operation is suspended while the alarm is active. The alarm is
cleared and the engine will re-start when the water level falls below maximum limits.
• Pad Shear (Latching): The main or fuel enclosure has shifted from its pad mounting
position. APU operation is suspended. The alarm is reset when the unit is returned to its
original position and the Reset command is issued or the manual stop switch is activated.
The APU will not start if the pad shear magnet is not correctly installed below the pad
shear sensor.
• Low Fuel Pressure (Latching – after fi ve activations): Site fuel supply (propane-fueled
APU only) is insuffi cient for extended engine operation. The alarm is reset fi ve minutes
after the fuel supply is replenished.