ELEMENTARY DIAGRAM

An elementary diagram is a simplified circuit illustration.
Devices and components are not shown in their actual
positions. All control circuit components are shown as
directly as possible, between a pair of vertical lines
representing the control power supply. Components are
arranged to show the sequence of operation of the devices
and how the device operates. The effect of operating
various auxiliary contacts and control devices can be
readily seen. This helps in troubleshooting, particularly with
the more complex controllers.
This form of electrical diagram is sometimes referred to as
a “schematic” or “line” diagram.

Control and Power Connections for Across-the-Line Starters, 600 V or less

(From NEMA standard ICS 2-321A.60)

NEMA and IEC Controller Markings and Elementary Diagrams

NEMA and IEC Terminal Markings

Standard Elementary Diagram Symbols - SUPPLEMENTARY CONTACT SYMBOLS &Terms

SPST: Single Pole, Single Throw
SPDT: Single Pole, Double Throw
DPST: Double Pole, Single Throw
DPDT: Double Pole, Double Throw
N.O.: Normally Open
N.C.: Normally Closed
T.O.: Timed Open
T.C.: Timed Closed
PUT: Programmable Unijunction Transistor
SCR: Silicon Controlled Rectifier
Triac: Bidirectional Triode Thyristor
UJT: Unijunction Transistor

Standard Elementary Diagram Symbols - Wiring-capacitors-resistors-semiconductors

Standard Elementary Diagram Symbols -Transformers-Dc Motors-Ac Motors-Inductors

Standard Elementary Diagram Symbols - Push Buttons

Standard Elementary Diagram Symbols - Selectors

Standard Elementary Diagram Symbols - Switches