M A N U A L BUS TRANSFERS, MOTOR
C O N T R O L L E R S , AND FREQUENCY REGULATORS
CHAPTER LEARNING OBJECTIVES
Upon completing this chapter, you should be able to do the following:
Describe the procedures to use when performing
Describe the troubleshooting and maintenance
procedures for manual bus transfer (MBT)
corrective maintenance on motor controllers.
D e s c r i b e the principles of operation of
Identify the different types of electric controllers.
Describe the principles of operation of various
Identify the components of motor generators and
types of motor controllers.
their principles of operation.
Describe the procedures for troubleshooting
Describe the procedures for troubleshooting and
p e r f o r m i n g corrective maintenance on
normal power to ship's emergency power, the locking
This chapter discusses the troubleshooting and
maintenance procedures for manual bus transfers
bar must be manually loosened and moved before the
(MBTs), motor controllers, and frequency regulators. To
positions of the switches can be changed. Trouble-
troubleshoot and maintain these components, you need
shooting should be done according to the technical
to have an understanding of the characteristics, uses, and
manual associated with the equipment. Maintenance of
operating principles of the components. Because
the MBT switch should be done according to the
interior communications and weapons systems aboard
modern Navy ships require closely regulated electric
applicable PMS cards.
power for proper operation, you also need to have an
understanding of closely regulated power supplies to
troubleshoot and maintain frequency regulators.
Because equipage in special power applications aboard
ship is so diverse, little is said about troubleshooting or
Controllers are commonly used for starting large
maintenance of MBT switches and frequency regula-
motors aboard ship to reduce the amount of current they
tors. In studying this chapter, you should remember to
require when started. The starting current of huge
refer to the manufacturer's technical manual when
motors is usually several times higher than the running
troubleshooting the equipment and to the applicable
current. If controllers are not used for starting, motors
maintenance requirement card (MRC) for maintenance
and the equipment they drive may be damaged, or the
operation of other equipment in the same distribution
MANUAL BUS TRANSFER SWITCHES
system may be affected adversely. By definition, a
motor controller is a device (or set of devices) that serves
MBT switches are commonly used for nonvital
to govern, in some predetermined manner, the operation
equipment aboard ship. They consist of two make or
of the dc or ac motor to which it is connected.
break switches and a locking bar. To transfer from