DOE-HDBK-1016/1-93
Electrical Diagrams and Schematics
ELECTRICAL DIAGRAMS AND SCHEMATICS
ELECTRICAL DIAGRAMS AND SCHEMATICS
To read and interpret electrical diagrams and schematics, the basic symbols and
conventions used in the drawing must be understood. This chapter concentrates
on how electrical components are represented on diagrams and schematics. The
function of the individual electrical components and the theory behind their
operation is covered in more detail in the Electrical Science Handbook.
EO 1.1 IDENTIFY the symbols used on engineering electrical drawings for
the following components:
a.
Single-phase circuit breaker
(open/closed)
b.
Three-phase circuit breaker
(open/closed)
c.
Thermal overload
d.
"a" contact
e.
"b" contact
f.
Time-delay contacts
g.
Relay
h.
Potential transformer
i.
Current transformer
j.
Single-phase transformer
k.
Delta-wound transformer
l.
Wye-wound transformer
m. Electric motor
n.
Meters
o.
Junctions
p.
In-line fuses
q.
Single switch
r.
Multiple-position switch
s.
Pushbutton switch
t.
Limit switches
u.
Turbine-driven generator
v.
Motor-generator set
w. Generator (wye or delta)
x.
Diesel-driven generator
y.
Battery
EO 1.2 Given an electrical drawing of a circuit containing a transformer,
DETERMINE the direction of current flow, as shown by the
transformer's symbol.
EO 1.3 IDENTIFY the symbols and/or codes used on engineering electrical
drawings to depict the relationship between the following components:
a.
Relay and its contacts
b.
Switch and its contacts
c.
Interlocking device and its interlocked equipment
EO 1.4 STATE the condition in which all electrical devices are shown, unless
otherwise noted on the diagram or schematic.
EO 1.5 Given a simple electrical schematic and initial conditions, DETERMINE
the condition of the specified component (i.e., energized/de-energized,
open/closed).
Rev. 0
PR-03
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