Change Over Switches

Question 1

Essential equipment and requirements

Answer 1

•Essential equipment provided with two supplies:

• Normal
• Alternative
• Switching between supplies is done with changeover switches.
• Three categories of changeover switch:
• automatic change-over switch (ACOS)
• Remote Operated Change-over switch (ROCOS)
• Hand Change-Over switch (HCOS)

Question 2

Change over switches

ACOS Automatic change over switch

Answer 2

• Works with normal and alternative supplies.
• Automatic change to alternative supply of normal fails.
• Provides power to an HCOS

Question 3

ROCOS Remote Operated Change-Over Switch

Answer 3

• Operated by hand from a remote location.

* Operating switch located in ship’s control centre.

Question 4

HCOS Hand Change-Over Switch

Answer 4

Three types of hand change over switch

• Normal/Alternative
• Normal/Emergency
• Normal/Alternative/Emergency

Question 5

HCOS Hand Change-Over Switch

Answer 5

• Supply source position must be selected by hand.
• Emergency position used with damage control cables.
• Always kept in normal position.
• Position never changed whole equipment running.