by AN numbers and those designated by MS numbers.
AN numbers were formally used for all supply items
check the microswitch.
cataloged jointly by the Army and Navy. Many items,
When a microswitch is faulty, it must be replaced. The
especially those of older design, continue to carry the
technical manual for the equipment specifies the exact
AN designator even though the supply system has
r e p l a c e m e n t switch. If you must use a substitute
shifted over to MS (military specification) numbers.
microswitch, observe the following guidelines. The
Although AN specification numbers for connectors
substitute microswitch must have all the following
have been replaced by MS numbers, you may still hear
characteristics:
connectors referred to as AN connectors.
At least the same number of poles
Electrical connectors (cannon plugs) provide a
detachable means of coupling between major
At least the same number of throws
components of electrical equipment. The construction
The same number of breaks
of these connectors permits them to withstand the
extreme operating conditions imposed by continuous
At least the same number of positions
service. They must make and hold electrical contact
without excess voltage drop despite extreme vibration,
A voltage rating equal to or higher than that of
rapid shifts of temperature, and so forth.
the original microswitch
A current rating equal to or higher than that of the
Types
original microswitch
Electrical connectors vary widely in design and
A physical size compatible with the mounting
application. Each connector consists of a plug assembly
As already mentioned, microswitches do not fail very
and a receptacle assembly. The two assemblies are
o f t e n . There is, however, a need for preventive
coupled by some type of coupling device (coupling nut,
maintenance. Periodically check the switches for smooth
pressure fitting, and so forth). Each assembly consists
and comet operation, physical damage, and corrosion at
of an aluminum shell containing an insulating insert,
the terminals. You can inspect most microswitches visually
which holds the current-carrying contacts. The plug is
for corrosion and damage. Check the operation of the
usually attached to a cable end and is the part of the
switch by moving the actuator. When the actuator moves,
connector on which the coupling device is mounted. The
you can feel whether the microswitch operation is smooth
receptacle is the half of the connector to which the plug
or seems to have some friction To check the actual
is coupled. The receptacle is usually mounted on a part
switching, observe the operation of the equipment or check
of the equipment.
the microswitch with a meter.
There are wide variations in shell type, design, size,
layout of contacts, and style of insert. Six types of
MAINTAINING ELECTRICAL CON-
connector shells are shown in figure 5-7.
NECTORS AND MULTICONDUCTOR
Connector MS 3100 is a wall-mounting receptacle.
CABLES
It is intended for use with a conduit to eliminate the need
The proper installation and maintenance of the
for installed conduit boxes.
various electrical and electronic propulsion systems are
very important to the GSE. Multiconductor cables and
electrical connectors are a major part of the ship's
electrical and electronic propulsion system. The repair
of battle damage, alterations, and some electrical repairs
require that you make changes or additions to the
equipment's cables and connectors.
ELECTRICAL CONNECTORS
On gas turbine-powered ships, electrical
connectors
are commonly called cannon plugs. In the
following
discussion, the word connector is used in
a general
Figure 5-7.--Types of connector shells.
sense. It applies equally well to connectors
designated
5-8
