25 - Synchronization Check Relay
27 - Under voltage Relay
27L - Under Voltage Lamp
32 - Reverse Power Relay
32L - Reverse Power Lamp
40L - Loss of Excitation Lamp
40 - Loss Of Excitation Relay
46 - Current Imbalance Relay
46L - Current Imbalance Lamp
46T - Current Imbalance Timer
47 - Undervoltage/Phase Sequence Relay
50 - Instantaneous Overcurrent Relay
51 - Time Over Current Relay
51L - Over Current Lamp
52 - Circuit Breaker
59 - Over Voltage Relay
62 - Time Delay Relay
65 - Governor
81O - A relay for generator overfrequency
81U - A relay for generator underfrequency
86 - Lockout Relay
87 - Machine Differential Relay
A - Ampere
AC - Alternating Current
ADEM - Advanced Diesel Management
AI - Analog Input
ALM - Alarm Module
ALS - Alarm Silence Push Button
ALT - Alternator
AMR - Auto Mode Relay (EMCP in Auto)
AN or ANN - Annunciator Module
AR - Arming Relay
ASL - Automatic Start Lamp
ASOS - Air Shutoff Solenoid
ASR - Air Shutoff Relay
ASSS - Automatic Start/Stop Switch
ASTR - Automatic Start Relay
ASSV - Air Start Solenoid Valve
ATB - AC Transformer Box
ATS - Automatic Transfer Switch
AUX - Auxiliary
AUTO - Automatic
AWG - American Wire Gauge
BLM - Base Load Module
BATT - Battery
BC - Battery Charger
BCA - Battery Charger Ammeter
BCF - Battery Charger Failure
BP - Bus Plug
BPT - Bus Potential Transformer
B- - Battery Negative
B+ - Battery Positive
C - Common
C - Capacitor
CAM - Custom Alarm Module
CAR - Common Alarm Relay
CB - Circuit Breaker
CBCL - Circuit Breaker Close Lamp
CBCR - Circuit Breaker Close Relay
CBOL - Circuit Breaker Open Lamp
CBOR - Circuit Breaker Open Relay
CBR - Circuit Breaker Relay
CBS - Circuit Breaker Switch
CCM - Customer Communication Module
CCW - Counter Clockwise
CDL - Cool Down Lamp
CDM - Engine Cool Down Timer Module
CDTR - Cool Down Timer Relay
CDVR - Caterpillar Digital Voltage
CIM - Customer Interface Module
CLFLS - Critical Low Fuel Level Switch
CLPR - Close Permission Relay
CPT - Circuit Breaker Power Transformer
CR - Control Relay
CT - Current Transformer
CTR - Crank Termination Relay
CTSB - CT Shorting Block
CW - Clockwise
D - Diode
DBR - Dead Bus Relay
DC - Direct Current
DC LTS - DC Lights
DCPS - DC Power Supply
DCT - Droop Current Transformer
DCV - DC Voltmeter
DCV - Direct Current Volts
DI - Digital Input
DIO - Digital Input/Output Module
DS - Disconnect Switch
DIST - Distribution Block
DO - Digital Output
DT - Distribution Transformer
DTCB - Distribution Transformer Circuit Breaker
ECLC - Engine Coolant Loss Connector
ECLS - Engine Coolant Loss Sensor
ECS - Engine Control Switch
ECTS - Engine Coolant Temperature Sensor
EFCR - Electrical Fault Cool Down Relay
EFCRX - Electrical Fault Cool Down Relay
EFL - Emergency Fuel Light
EG - Electronic Governor (Speed Sensing)
EGA - Electronic Governor Actuator
EGA - Engine Governor Actuator
EGR - Electronic Governor Relay
EGR - Engine Governor Relay
EHC - Ether Hold-In Coil
EHS - Ether Hold-In Switch
EMCP - Electronic Modular Control Panel
ENFR - Engine Failure Relay
EOTC - Connector for the Engine Oil Temperature Sensor
EOTS - Engine Oil Temperature Sensor
EOPS - Engine Oil Pressure Sensor
EPC - Ether Pull-In Coil
EPS - Ether Pull-In Switch
ERR - Engine Run Relay
ES - Ether Solenoid
ESL - Emergency Stop Light
ESPB - Emergency Stop Push Button
ESR - Enable Sensor Relay
F - Fuse
FAR - Fuel Alarm Relay
FCR - Fuel Control Relay
FCS - Fuel Transfer Control Switch
FCTM - Fuel Control Timer Module
FES - Float Equalize Switch
FLA - Full Load Amps
FLG - Fuel Level Gauge
FLT - Fault
FM - Flasher Module
FMS - Fuel Transfer Mode Switch
FPL - Failed to Parallel Lamp
FPT - Failed to Parallel Relay
FS - Fuel Sensor
FSOS - Fuel Shutoff Solenoid
FTP - Fuel Transfer Pump
FTR - Fuel Tank Rupture
GCB - Generator Circuit Breaker
GCM - Gauge Control Module
GCT - Ground Sense Current Transformer
GEN - Generator
GFR - Generator Fault Relay
GMR - Generator Multifunction Relay
GND - Ground
GOL - Generator On Load
GOV - Governor
GPC - Generator Paralleling Controller
GPHI - Ground Post (High Voltage)
GPLO - Ground Post (Low Voltage)
GRR - Global Run Request
GS - Governor Switch
GSC - Generator Set Control
GSH - Generator Space Heater
GSM - Governor Synchronizing Motor
GSR - Generator Synchronize Relay
GSOV - Gas Shutoff Valve
HRN - Horn Signal
Hz - Hertz
IC - Initiate Contact
IDS - droop isochronous switch
IRS - Idle/Rated Switch
JWH - Jacket Water Heater
JWHR - Jacket Water Heater Relay
kW - Kilowatt
KWR - Kilowatt Level Relay
L - Load Leads
LCS - Louver Control Switch
LCT - Louver Close Timer
LDR - Louver Driver Relay
LFL - Low Fuel Level Light
LFLAS - Low Fuel Level Alarm Switch
LFS - Latching Fuel Control Solenoid
LOAL - Low Oil Alarm Lamp
LOLAS - Low Oil Level Alarm Switch
LOLS - Low Oil Level Switch
LOT - Louver Open Timer
LPR - Louver Position Relay
LSS - Local Start Switch
LSR - Local Start Relay
LTR - Lamp Test Relay
LWLAS - Low Water Level Alarm Switch
LWTL - Low Water Temperature Light
MAN - Manual
MB - Modbus
MCM - 1000 Circular Mils
MFM - Multiple Function Meter
MPU - Magnetic Speed Pickup
MRUS - Manual Return to Utility Switch
MS - Motor Starter
NAC - Normal After Close
NAT - Normal After Trip
NC - Normally Closed
NEU - Neutral
NIA - Not In Auto
NO - Normally Open
OCL - Over Crank Light
OCR - Over Current Relay
OCT - Over Crank Timer
OFS - Overflow Switch Fuel Tank
OIP - Operator Interface Panel
OMR - Off Mode Relay (EMCP in Off)
OP - Open
OPG - Oil Pressure Gauge
OPL - Oil Pressure Light
OSL - Over Speed Light
OSR - Overfill Safety Relay
OSS - Overfill Safety Switch
OVR - Over Voltage Relay
OTS - Over current Trip Switch
OVL - Overload
P - Plug in Connector
PAR - Utility Paralleling Relay
PB - Push Button
PCS - Paralleling Controls Switch
PEEC - Programmable Electronic Engine Control
PF - Power Factor
PFM - Power Factor Meter
PFTD - Power Factor Transducer
PL - Panel Illumination Light
PLBL - PLC Low Battery Lamp
PLC - Programmable Logic Controller
PLCL - PLC Running Lamp
PLCR - PLC Running Relay
PLS - Panel Light Switch
PLTR - Power Level Trip Relay Potentiometer
POS - Positive
POT - Potentiometer
PP - Prelube Pump
PPMS - Prelube Pump Magnetic Switch
PPPS - Prelube Pump Pressure Switch
PSHD - Primary Unit shield
PRG - Programming Port
PT - Potential Transformer
PTL - Pull To Lock
PUR - Primary Unit Relay
PWM - Pulse Width Modulation
R - Resistor
RAN - Remote Annunciator
RBS - Rupture Basin Switch
RCP - Receptacle
RCS - Remote Control Switch
RDM - Relay Driver Module
REA - Reactor
REF - Reference
RPL - Reverse Power Light
RPR - Reverse Power Relay
RPSR - Reverse Power Slave Relay
RR - Run Relay
RSS - Remote Start Switch
RUL - Return to Utility Lamp
SA - Surge Arrestor
SAP - Speed Adjust Potentiometer
SAR - System in Automatic Relay
SAS - Starting Aid Switch
SASV - Start Aid Solenoid Valve
SATS - Start Aid Temperature Switch
SBS - Stand By Switch
SC - Shunt Coil
SCADA - Supervisory Control and Data Acquisition
SDL - Sensors Disabled Light
SDR - Shutdown Relay
SDRX - Shutdown Relay
SH - Spare Heater
SHD - Shield or Shielded
SHTC - Circuit Breaker Shunt Trip Coil
SIG - Signal
SL - Synchronizing Light
SLM - Synchronizing Light Module
SLR - Synchronizing Light Resistor
SM - Starter Motor
SMMS - Starter Motor Magnetic Switch
SMR - Starter Motor Relay
SP - Speed Adjust Potentiometer
SPM - Synchronizing Parallel Module
SPR - Spare
SR - Slave Relay
SS - Synchronizing Switch
SSR - Synchronizer Select Relay
STPR - Stop Relay
SYNC - Synchronizing Scope
T - Generator Line Leads
TB - Terminal Block
TD - Time Delay Relay
TDBCR - Time Delay Breaker Close Relay
TDUBC - Time Delay Utility Breaker Close
THM - Thermostat
TMR - Timer
TP - Terminal Point
TP - Trim Potentiometer
TR - Trip Relay
TRP - Trim Potentiometer
TSC - Transfer Switch Position Indicating Contact
TST - Test Signal
UBCL - Utility Breaker Closed Lamp
UBOL - Utility Breaker Open Lamp
UCBR - Utility Circuit Breaker Relay
UCR - Utility Close Relay
ULOL - Utility Lock Out Lamp
ULOR - Utility Lock Out Relay
UPT - Utility Potential Transformer
USL - Utility Synchronization Lights
USS - Utility Synchronization Switch
UTR - Utility Trip Relay
UTTL - Utility Transfer Trip Lamp
UTTR - Utility Transfer Trip Relay
UTTS - Utility Transfer Trip Relay Switch
V - AC Voltmeter
VAP - Voltage Adjust Potentiometer
VAR - Voltage Adjust Rheostat
VAR - Volts Amperes Reactive
VARM - Volts Amperes Reactive Meter
VARTD - Volts Amperes Reactive Transducer
VBR - Voltage Buildup Relay
VBT - Voltage Buildup Timer
VCR - Voltage Control Relay
VDC - Volts Direct Current
VDR - Voltage Droop Rheostat
VPAP - VAR or Power Factor Adjust Potentiometer
VPC - VAR or Power Factor Controller
VR - Voltage Regulator
VRAR - Voltage Regulator Alarm Relay
VRFR - Voltage Regulator Fault Relay
WHI - Watt Hour Integrator
WM - Wattmeter
WT - Water Temperature
WTD - Watt Transducer
WTG - Water Temperature Gauge
WTL - Water Temperature Light
XDUCER - Transducer
XVR - Change Over Relay
XVTD - Change Over Time Delay
Z - Zener Diode