Alpha Technologies AlphaGen PN-6x-T 7.5kW 48VDC - Installation and Operation Manual - Manual (Page 37)

745-020-B0-003, Rev. C 37
ECM
4.0 The Engine Control Module
The Engine Control Module (ECM) controls and monitors the generator’s Auxiliary Power Unit (APU).
The ECM is a two part assembly made up of the ECM Printed Circuit Board (ECM PCB) and the
Generator Remote Interface (GRI) board. The ECM PCB/GRI assembly is mounted to the top of the
generator housing, to the left of the ignition battery. The GRI is attached to the ECM PCB via three
ribbon cables.
The GRI powers the ECM and steps down high voltage. It provides interface connectors for the
enclosure sensors, engine controller, battery sense, line sense, and other equipment. Depending on
the standby powering confi guration, the ECM and generator combination are collocated with other
Alpha equipment such as power supplies and batteries, or installed remotely. The ECM 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 starts the APU to prevent the backup batteries
from discharging to a level that could compromise the ability of the system to provide a continuous,
reliable source of power.
The ECM monitors the entire system for abnormal operating conditions such as low engine oil
pressure, engine over-temperature, gas leaks, enclosure pad shear, etc. If certain abnormal
conditions or alarms are present, the ECM prevents the generator from starting or shuts it down
immediately. This provides public safety, and prevents damage to the APU. The system operator can
override the ECM and control the APU manually or remotely.
The ECM provides an interface between the APU and Alpha communication devices. The ECM
controls and monitors the APU and responds 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 front panel LEDs, or by four “Form C” relay contacts. The ECM is
capable of reporting 9 major alarms, 8 minor alarms, and 2 notifi cations.
Fig. 4-1, Location of Engine Control Module (ECM)