Tait T809-10, Service Manual

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20 Installation Guidelines
MBZ-00001-01
November 2004 Copyright © 2004 Tait Electronics Ltd
3.2 Wiring and Protection Devices
For safety reasons, all T800 subracks must be fitted with a protection device (fuse or cir-
cuit breaker) positioned after the output of the T809-10 power supply. The T809-10 out-
puts a high current when overloaded – up to 48A for an output short circuit.
3.2.1 Protection Device Positioning
The location of the DC output protection device depends on whether or not the remote
sense feature is used – refer to Sections 3.2.1.1 (When Remote Sense Is Not Used) and
3.2.1.2 (When Remote Sense Is Used).
3.2.1.1 When Remote Sense Is
Not
Used
When the remote sense is not used, the DC output protection device should be located
as close as possible to the output of the power supply, as shown in the diagram:
Figure 3.1 Protection device without remote sense
3.2.1.2 When Remote Sense
Is
Used
When installing a protection device with the remote sense connected:
• Connect the sensing wires to the
power supply side
of any protection
device. Failure to do this will cause the power supply to shut down if the
protection device opens the circuit. This happens because the power supply
senses 0V across the remote sense terminals and the output voltage then
increases to compensate for the apparent reduction.
• Connect the sensing wires as close as possible to the load terminals to
ensure the remote sense feature functions effectively.
As a consequence of applying these procedures, the protection device will be located
close to the load, as shown in the diagram below (Figure 3.2).
Heavy gauge wire
Load
(e.g. transmitter)
Power supply
+
–
+V
–V
Protection
device