M800-00
T807/808 General Information
B1.3
Copyright TEL
31/08/96
1.1
Introduction
The T807/808 is a heavy duty, lightweight switching power supply capable of supply-
ing up to 15A (T807) or 25A (T808) at 11 to 14V DC. The units require a mains supply of
230V/50Hz or 115V/60Hz (nominal values) which can be internally selected with a
switch (if fitted) or wire links. Remote sensing of the output voltage is available as a
standard feature: if connected, it will ensure that the output voltage remains within
±1% of the preset level from no-load to the full specified load, over the specified mains
voltage and temperature ranges (refer to Section 7.6).
The T807/808 power supply is designed to power T800 series base stations. Specifically,
the T807 will power 50W base stations, while the T808 will provide the current require-
ments for 100W base stations.
Electromagnetic compatibility (EMC) and operator safety are both important and criti-
cal parameters for the trouble free functioning of a switching power supply. Refer to
Section 1.2.3 (EMC) and Section 1.2.4 (safety) for current specifications.
The T807/808 is protected against damage caused by faults in the line or load, or by
temperature variations (refer to Section 1.2 for specifications). The protection features
include:
mains transient suppression
mains inrush current limiting
mains undervoltage lockout
soft start
output current limiting
output voltage limiting
output reverse polarity protection
overtemperature shutdown.
The output voltage and current limit and overvoltage points are all adjustable and are
preset during manufacture.
Note:
On earlier model power supplies with an issue 03 PCB, the overvoltage
point is
not
adjustable.
The T807/808 can be used to float charge a 12V battery under constant voltage condi-
tions. The current limit circuit prevents the charging current from being excessive if the
battery is completely discharged, and the internal rectifier diode will blow the external
fuse in the event of the battery being accidentally connected in reverse. (refer to Section
7.5). An alarm output provides a logic 0 (0V) in the case of a mains and/or power sup-
ply failure, even if a battery is connected to the 13.8V output.
Note:
On issue 03, a transient suppression diode across the power supply output
prevents any damage if the battery is accidentally connected in reverse.
A T807/808 may be housed together with other Tait fixed equipment modules in a
standard 484mm (19") rack frame, where it occupies the space of one standard 60mm
module, to give an attractive and convenient installation.
Artisan Scientific - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisan-scientific.com
