ARMY TM 9-6115-671-14
AIR FORCE TO 35C2-3-446-32
MARINE CORPS TM 09249A/09246A-14A
1-16
SECTION III. PRINCIPLES OF OPERATION
1.15
INTRODUCTION.
This section contains functional descriptions of the generator set. How the controls and indicators
interact with the system is explained as well as the location and description of major components.
1.16
PRINCIPLES OF OPERATION.
1.16.1
Digital Control System (DCS).
1.16.1.1
The DCS is a closed-loop system providing the operator with real-time system status information and
control. It includes automatic shutdown features if critical components fail to protect the generator set
from damage and to prevent damaging output power and voltage levels. It includes a digital computer
using software to process inputs from the generator set and from the operator. The DCS accepts
operator commands to adjust various generator set parameters such as frequency and voltage. The
DCS also facilitates operating two or more generator sets in parallel. The DCS can be operated at the
generator set or from a remote location using an IBM-compatible personal computer (PC)
1.16.1.2
In the event that the computer operating software is lost or operating incorrectly, the software must be
restored. Procedures are provided for TQG remote software restoration in Paragraph 2.13.2.
1.16.1.3
Eight major components or modules are included in the DCS: The DCS speed control unit, automatic
voltage regulator, load sharing synchronizer, I/O interface module, backplane module, electric actuator,
computer interface module (CIM), and keypad assembly. The DCS provides multiple, integrated
functions as the controller of the fault, governor, and voltage regulation systems, as described below.
1.16.1.4
The CIM is the primary operator interface with the DCS. It is a self-contained IBM compatible
computer with an AMD 486 processor running the Windows CE operating system. An internally lit
Liquid Crystal Display (LCD) screen provides the operator with status displays and control capability.
A cursor symbol on the display is controlled by the keypad assembly, which is a set of four arrow keys
and a SELECT key to enter commands. The load sharing synchronizer is used when paralleling the
generator set to a main bus or to another generator set. This module provides signals to the DCS speed
control unit to adjust engine speed settings to maintain a match between the outputs of the two
generator sets. The I/O interface module controls and interfaces with all the other components in the
DCS. For example, it receives inputs from engine sensors and converts them for use by the CIM. Most
of the DCS signals, including control panel inputs, are routed through this module. The status of the
I/O interface module is indicated by a green HEARTBEAT light emitting diode (LED) which blinks at
a rate of approximately two times per second to indicate the module is operational.
The backplane module is an installation point for three DCS modules and for the main electrical
connectors from the AC generator. It connects the front panel switches and these DCs modules with
the I/O interface module. This module simplifies the wiring inside the DCS control box by placing
many interconnections onto one circuit board assembly. This module also includes diagnostic
indicators for the DCS. The other DCS modules are discussed in paragraphs below.
1.16.2
Fault System.
1.16.2.1
The Fault System (Figure 1-19) protects the generator set and any connected load against the potential
faults described below and provides an indication of any incurred fault. The following summary of the
Fault System will assist in understanding the operation of other generator set systems. Additional
details relating to specific protection devices are provided in the descriptions of the respective systems.
