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34
Separate voltage transformer power
supply
In some locations, a separate voltage
transformer (VT) is installed to provide
power to the RCU. This VT should be:
Fused and rated on the high-voltage
side to match the supply conditions.
The secondary voltage should be
115 Vac or 230 Vac as preferred and
rated at 150 VA.
A fuse on the secondary adjacent to the
VT is recommended to protect from
wiring faults of the pole. The fuse
should be rated for the VT and wiring.
2 A recommended.
A method of isolating the RCU from the
source supply is required for safe
operation. The fuse and the isolating
means must be located at the source
end of the circuit.
For most primary voltage ratings Siemens
can supply a suitable VT.
The VT secondary power supply cable
specification and installation process is
identical to the auxiliary power supply cable
specification and installation in Auxiliary
power supply section on page 30.
Hazardous voltages and high-speed moving parts.
Will cause death, serious injury and property damage.
Do not work on energized equipment. Always de-energize and ground the
lines before working on the equipment.
De-energize and isolate auxiliary power supply at the source before
removing power supply cover, and install power supply cover before
energizing auxiliary power to the RCU.
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