Alpha Technologies ECM - Manual (Page 13)

13 TM 744-862-C0-003 Rev.C
Engine Control Module (ECM)
1.1 Introduction
The primary purpose of Alpha’s Engine Control Module (ECM) is to control
and monitor an AlphaGen Auxiliary Power Unit (APU) set, such as the CE-3X2
3.0kW and 5.0kW Series Engine-Generators. The ECM is used in conjunction
with a Generator Remote Interface (GRI) PCBA, often referred to as the Power
Board. The ECM/Power Board Assembly is mounted to the top of the Engine-
Generator housing, to the left of the ignition battery. The Power Board is
attached to the ECM via three ribbon cables.
The GRI provides power to the ECM, steps down high voltages for the ECM,
and provides interface connectors for the enclosure sensors, engine controller,
battery sense, line sense, and other equipment. Depending upon the standby
powering configuration, the ECM and generator combination are installed
remotely, or co-located, with other Alpha equipment such as power supplies
and batteries.
The Engine Control Module monitors AC line and DC bus status to determine
when to start and stop the APU. In the event of an extended power outage
or low battery bus voltage, the ECM will start the APU to prevent the backup
batteries from discharging to a reduced voltage level which would compromise
the ability of the system to provide a continuous, reliable source of power.
In addition to starting the APU, the ECM monitors the entire system for
abnormal operating conditions such as low engine oil pressure, engine over-
temperature, gas leak, enclosure pad shear, etc. If certain abnormal
conditions or alarms are present, the ECM will either prevent the generator
from starting or shut it down immediately. This provides for public safety,
while preventing any serious damage to the APU. The system operator also
has the ability to override the ECM and control the APU manually or remotely.
Finally, the ECM provides the interface between the APU and Alpha
Technologies' communication devices. The ECM is designed to control and
monitor the APU while responding to commands and queries from a system
controller via an isolated RS-485 data bus. Status information and alarms can
be read from the ECM remotely via the data bus, locally from the Light Emitting
Diodes (LEDs) on the unit’s front panel, or by an optically isolated transponder
interface. The ECM is capable of reporting 9 major alarms, 8 minor alarms, and
2 notifications.
Section 1, System Overview