Applying A Backup Temperature Probe; Auxiliary Ct Input For Calculated Winding Temperature; Figure 3.11: Split Core Ct Installation - Advanced Power technologies TTC-1000 Instruction & Operation Manual

Attention!
The probe shield wires MUST be grounded to the chassis of the TTC-1000.
Failure to properly ground the shield wires may result in false
measurement and/or false temperature probe alarms. Do not cut off the
shield wire.

3.3.5 Applying a Backup Temperature Probe

The TTC-1000 has the ability to detect a single probe failure and automatically
switch to a working backup probe. To implement a backup probe installation,
connect the primary and backup probes to the unit as described above.
The TTC-1000 looks at the probe names to determine which probe to use for
which function, such as TOP OIL. It looks at the channels starting at probe
channel 1, then 2, then 3. If it finds two TOP OIL probes, it considers the first
one in the list as the primary probe. So make sure to connect your primary probe
to channel 1 and your backup probe to channel 2 (or 2 & 3 respectively). Name
the redundant probe channels the same (i.e. TPROBE1 NAME=TOP OIL and
TPROBE2 NAME =TOP OIL). Refer to section 4.5 for details on naming probe
channels.
If probe channel one becomes non-functional, the TTC-1000 will automatically
switch to using channel two for TOP OIL.

3.4 Auxiliary CT Input for Calculated Winding Temperature

A split core CT is supplied for each CT input which is intended to be applied over
the secondary leads from the bushing CT. To apply the CT, first open the window
by inserting a small screwdriver in the
clasp holding the core halves closed.
Select a CT secondary tap ensuring that it
is either shorted or already in use. It is
recommended that B phase CT be used
for this purpose. Wrap the wire with
several layers of electrical tape and apply
the split core CT over the wire and snap it
closed. It is highly recommended that a
cable tie be applied under the split core
CT to keep it from sliding down against
the lug. Figure
assembly of the split core CT onto the
bushing CT secondary.
The range of the main board CT input is 0-10 amperes. Currents over 10
amperes will cause errors in current readings. Likewise, currents under 0.5
amperes will have reduced accuracy. Best operation will be with the CT current
around 5.0 amperes at full load. Wrapping the CT lead through the split core
3.11 illustrates the
BUSHING CT
SECONDARY
SPLIT CORE
CT

Figure 3.11: Split Core CT Installation

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