Dictionary of Abbreviations


AC                            Alternating Current

ACR                         Auxiliary Control Relay

AHF                        Adjustable Holding Force

ALT ACT               Alternate Action

ATB                         Armature Thru Bolt

ATD                         Adjustable Time Delay

ATMS                     Armature Template Machine Screw

AWG                       American Wire Gauge

BG                            Break Glass

BP                            Bolt Position Pin

BES                         Bolt Extended Switch

BPS                         Bolt Position Switch

BRS                        Bolt Retracted Switch

CT                           Center Tap

DA                          Delayed Action

DC                          Direct Current

DT                          Double Throw

DPS                       Door Position Switch

ER                          Emergency Release

HM                        Hollow Metal Door

LC                          Line Cord

LF                          Extra Long Housing – Horizontal Mount

LW                        Left Hand

LV                          Extra Long Housing – Vertical Mount

LHR                      Left Hand Reverse

M                            Magnet

MR                        Manual Release

MBS                     Magnetic Bond Sensor

MSC                     Manual Station Control

NC                         Normally Closed

NO                         Normally Open

PB                          Push Button

PS                           Power Sensor

PCU                       Power Control Unit

RB                          Rectifier Block

RH                          Right Hand

RR                          Residual Release Module

RHR                      Right Hand Reverse

SP                           Switch Plate

ST                           Single Throw

SCR                        Separate Control Relay

SPDT                     Single Pole Double Throw

SPNC                     Single Pole (Single Throw) Normally Closed

SPNO                    Single Pole (Single Throw) Normally Open

SPST                     Single Pole Single Throw, Maintained

TJ                           Top Jamb

UPS                       Uninterruptible Power System

VT                          Voltage Trimmer

WD                        Wood Door