Skip to Main Content
Modern Electrical Installation for Craft Students, 3rd Edition
book

Modern Electrical Installation for Craft Students, 3rd Edition

by Brian Scaddan
November 2013
Intermediate to advanced content levelIntermediate to advanced
182 pages
6h 6m
English
Newnes
Content preview from Modern Electrical Installation for Craft Students, 3rd Edition
68 Cells, batteries
and
transformers
Emergency lighting
One important
use for the
secondary cell
is to
provide alternative
supplies
to a
lighting installation
in the
event
of a
mains failure.
There
are
two main systems
of
emergency lighting:
the non-
maintained system,
and the
maintained system.
In
the
system shown
in
Diagram
80
the emergency lights
are
only
energized when
a
mains failure occurs. The contactor will de-energize,
the contacts close
and the
lights will
be fed
from
the
battery.
In
a
maintained system (Diagram 81)
the
lights
are fed
from
two
sources,
a.c. and
d.c. When
the
mains fail,
the
contactor de-energizes
and
the
contacts chang ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Electrical Calculations and Guidelines for Generating Station and Industrial Plants

Electrical Calculations and Guidelines for Generating Station and Industrial Plants

Thomas E. Baker

Publisher Resources

ISBN: 9781483106205