relay Abbreviations and Numbers
A relay that functions on a given value of undervoltage
number 27 undervoltage relay
most logical place to start analyzing system problems or malfunctions.
block
closing coil
CC
A sheet
24-36
A
Ammeter
a relay with either a definite or inverse time characterisic that functions when the current in a AC circuit exceeds a predetermined value
51- ac time overcurrent relay
used in conjunction with elementary diagrams for component and wiring locations. show all connections within an enclosure
wiring diagrams
trip coil
TR
D sheet
8.5- 11
PB
push button
a relay that operates on given values of liquid pressure, gas pressure, flow, or level or on a given rate of change of these values,
63- liquid or gas pressure level or flow relay
used to represent the function of the system or components.
elementary
Time delay relay
TD
DR
11x 17
TDC
time delay closing
a relay that functions on a desired value of AC over current flowing in a predetermined direction
67- AC directional overcurrent relay
Troubleshooting means?
What two diagrams are best used for troubleshooting?
use a logical approach to locate a problem and fix it.
Wiring and schematic
trip relay
TR
title block location
bottom right hand corner
XSH
auxiliary switch
a device that controls a quantity such as voltage, current, power, speed, frequency, temperature, and load at a given value or between certain limits, for machines, tie lines, or other apparatus.
90- regulating device
provide component names and important information and show the electrical connections of all major components
one line
stops CB from sending trip signal over and over again
XY anti pump relay
identifying print number
R22-EA1 example
OSC
oscillograph