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M800-00
T807/808 Installation
B7.7
Copyright TEL
31/08/96
terminals (refer to Figure 7.2).
Note 1:
Ensure that the remote sense connections are made with the correct
polarity (i.e. "+" to "+" and "-" to "-") before the mains supply is connected.
Shorting of the remote sense connections on a running supply
before
they
are connected to the output wiring will result in the destruction of the
T807/808 overvoltage diode, D46 (refer to Note 4 below).
Note 2:
As the output voltage is factory set to 13.8V with
unconnected
remote
sense terminals, connection of these terminals will result in a slight
change in the nominal output voltage (i.e. from 13.8V to approximately
13.5V). If required, the nominal output voltage can be readjusted (refer to
Section 4.3.2).
Note 3:
When remote sensing and float charging are set up as part of a system, it is
recommended that the actual battery charging voltage is close to 13.8V (or
its temperature compensated equivalent). Voltages above or below the
nominal float charge value will mean either the battery is overcharged (high
voltage) or never fully charged (low voltage).
Note 4:
When a fuse and/or switch is fitted in the output wiring between the
power supply and the load, it is essential that the remote sensing is con-
nected to the
power supply side
of the switch or fuse, as shown in Figure
7.3.
Figure 7.3 Output Voltage Remote Sensing With Fuse And/Or Switch
Failure to do this will result in the destruction of the main rectifier diode D43
(Issues 05
& 07)
or the overvoltage diode D46
(Issue 03)
, in the T807/808 when the fuse or switch
is open. This happens when the power supply "sees" 0 volts across the remote sense ter-
minals and the output voltage is then increased to compensate for the apparent reduc-
tion of output voltage.
Remote
Sense
P
N
E
Mains
V Out
T807/808
Load
(e.g. Transmitter)
V DC
Fuse
Switch
Light Gauge Wire
Heavy Gauge Wire
+
+
_
_
+
_
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