SECTION 3
SYSTEM POWER SUPPLY
3.1
KMSD systems may be ordered for the following electrical services:
a.
120V, 60Hz
b.
120V, 50Hz
c.
240V, 60Hz
d.
240V, 50Hz
3.2
All systems require a storage battery-based 24VDC supply (1 ampere) for the power failure alarm.
3.3
Figure 3-1 shows the principle elements of the system's internal and external power supplies.
3.4
The entire smoke detecting system receives its normal operating power from the ship's lighting and power system
switchboard.
3.5
In the event of primary power failure, sufficient power for continuous normal operation is drawn from the ship's
service power system switchboard. The transfer is accomplished within the KMSD cabinet by means of relay K1
(main AC transfer relay).
3.6
On ships adequately equipped, transfer from normal power to emergency power may be accomplished at the
emergency lighting switchboard, and a single AC power line run to the KMSD cabinet.
3.7
The system receives 24 Volt battery power from the ship which is used to operate the power failure alarm. Audible
and visual power failure signals occur at the smoke detector cabinet and the repeater cabinet (when used).
3.8
Internally, the detecting cabinet provides two complete redundant 24 Volt DC regulated power supplies.
3.9
Voltage sensing devices and relays are arranged so the panel will automatically switch to the No. 2 (reserve) power
supply should the No. 1 (primary) power supply fail to maintain at least 85% of normal voltage under any load
condition.
3.10
Failure, including voltage outputs below 85% of nominal, of either power supply is indicated by illumination of the
power supply failure LED on the cabinet front panel together with the common trouble signal as long as the other
supply remains functional.
3-1
