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Current Transformers perform two main functions:
a) Accurate reproduction at a given ratio in a secondary
winding of the current passing through the primary winding.
b) Electrical separation between both windings.
These factors make it possible to:
• Separate the circuit in which measurements are taken,
which makes handling of the meters safer, because normally
one end of the secondary winding is grounded.
• Measure high currents with low current input meters,
therefore, whatever the primary rated current value may be,
the secondary current can remain a constant 5 or 1 Amp.
• Use a small cross section cable since the secondary
current is only 5 or 1 Amp. Other secondary currents are
available on request.
PLEASE SEE TECHNICAL INFORMATION - PDF FOR COMPLETE
INFORMATION |
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Meter Load and Connection Wire Loss |
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Loss occurs in
the lead between C.T. and the meter. This loss is measured
in VA and must be added to the meter load in all VA
calculations. When the meter is situated at a long distance
from the C.T., this loss can become greater than the meter
VA and therefore 1A C.T’s are recommended. |
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Accuracy
Class |
Various classes
of accuracy are available - the class selected depends upon
the application and the acceptable maximum permissible
deviation.
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Class 0.1 Class 0.2 |
Designed
to individual customer requirements for specific
applications in energy metering and control systems. |
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Class 0.5 |
Transducers, digital metering systems, control
systems and Watt, VAr, Phase Angle and Power Factor
meters. |
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Class 1 |
Recording meters and protection devices |
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Class 3 |
Industrial ammeters and maximum demand ammeters |
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Features / Benefits |
Integral
terminal cover which makes them 'safety' fail safe and saves
on installation time
High impact flame retardant, halogen free, polycarbonate
moulded case (UL94V0) which reduces the risk of mechanical
damage and propagation of fire
Class E (120°C) service temperature
Combined M4 No 1 posi/slot screw clamp/6.3mm
'Fast On' push on tag terminal connection for quicker
connection
Busbar or DIN rail or steel feet mounting hardware supplied
1 and 5 amp secondaries
Wide range of
apertures
Non standard ratios and secondaries available on request |
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Range / Performance |
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System voltage |
720V
maximum |
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Test voltage |
3kV for
1 minute |
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System frequency |
50/60Hz
(400Hz optional) |
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Short circuit thermal current (Ith) |
60 x
rated primarycurrent (lth)*: for 1 second |
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Overload withstand: |
1.2 x
rated current continuously |
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Dynamic current (Idyn) |
2.55 x
Ith |
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Saturation coefficient |
< 5 for
plain ring
< 10 for wound primary |
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Service temperature |
-20°C to
+85°C |
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Insulation class |
BS2757
Class E (IEC85) |
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Enclosure code |
IP40 |
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Integral terminal cover |
IP20B |
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Complies with |
BS7626:
1993, IEC 185: 1990 |
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Humidity |
Up to95%
RH (non condensating) |
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Secondary terminals |
Screw clamp: |
Up to
10mm2 cable |
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'Fast on': |
6.3mm
type |
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