Ametek TR-2100, Operation Manual

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TR-2100 User Manual 21
Current Inputs
The current inputs are derived from either a shunt resistor or an interposing CT connected in
series with the 1 Amp or 5 Amp secondary winding of a protection CT. In the latter case, a
burden resistor is fitted either inside the TR-2100 or on the CT module. The CT ratio and
burden resistor value are chosen to suit the maximum short circuit current level and
protection CT ratio. The actual nominal and full-scale values are given in the User
Specification.
There are a number of options available for interposing CTs. The most common is the
toroidal or ‘wedding ring’ type. Four of these are normally fitted to a DIN rail mounting
assembly. This type requires either shorting (disconnect) switches or a line outage, so that
the protection CT secondary can be wired to the interposing CT module.
The split-core and clamp-on CTs do not require an outage and are very simple to fit. These
are most popular on portable systems. Clamp types are available with sensitivities down to
1.4 A.
Special Analogue Inputs
By special arrangement, other input ranges can be set to suit transducers and other sources.
This ensures that the correct scaling and triggering values are used. To set special inputs, a
component change may be required on the input board, along with recalibration of the unit.
Some examples of other inputs that have been used are:
+/- 10 V industrial transducers
400 V for mains supply monitoring *
600 V for measuring rise in ground potential *
50 V – 150 V for recording tripping battery voltage
2V for Hall effect CT for monitoring battery current
* High voltage ranges require use of an external Voltage Divider Box, available from
AMETEK.
For non-sinusoidal signals, a DC input can be specified in the Display Station configuration.