| In Mobile and Marine power
systems, Undervoltage conditions occur during engine cranking, during the
application of heavy electrical loads, and by the gradual loss of battery
capacity. According to Military Standards, the battery voltage (with the engine OFF) in
a properly operating 12 Volt system can drop as low as 10 volts. In a 24/28
Volt system, it can drop to 20 volts. But, during engine cranking, the
battery voltage can drop to 6 volts! (see below)
This undervoltage can play
havoc with electronic equipment. Therefore, the STO-P UPS40 series
of Power Fault Protectors incorporates an internal backup battery to
provide 'fill-in' current during undervoltage conditions. A minimum of
45 Amps can be produced for short periods of time. For greater capacities, a larger external battery can be
employed. Switching is instantaneous - the backup power source is always
'online' - so there is never an interruption of power to the equipment.
Because of its smaller physical
size, the STO-P PFP15 series uses an external user supplied
battery for backup power. It supplies a maximum of 10 amps of 'fill-in'
current to equipment susceptable to undervoltage. (A total of 15 amps is
available to susceptable and non-susceptable equipment via two separate
leads.)
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