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Clamp-on Current Transducers
There are five basic types, with popular devices available ex-stock. All can be manufactured to customer’s exact specification.
Sales Team: +44 7871 375037
1. Hall Effect
Combined AC & DC input sensor with a voltage output.
These sensors combines a magnetic core with a gap into which is inserted a Hall Effect sensor — an electronic device which responds to a magnetic field. With associated electronic circuitry, the output is an image of the measured current. These devices can be supplied powered either from an external source or, for portable applications, a battery. A special model providing just a DC output is available.
Different models are available covering a range from 100Amp to 7,500Amp peak or DC.
2. Clamp-on Current Transformer
Since with a clamp-on CT the input has just one turn, the amplitude of the output current is reduced by the number of secondary turns. E.g. with a 1000 turns and a current of 1000 Amps, the output would be 1 Amp. Such basic CTs are therefore ideal for interfacing to legacy instruments which require 5 Amp or 1 Amp inputs, such as traditional kWh Meters.
For a 5 Amp output, medium & large models are available from ~ 250 Amp (depending on application) to 3000 Amp; with a 1 Amp output, small models are available at 100 & 200 Amp while medium & large as above.
3. Injection Clamps
Designed to inject an AC voltage signal into a cable to allow the route of the cable to be traced. Custom designed for each application.
4. Clamp-On Current Transformer or Transducer With AC Voltage Output.
Here, a resistor is fitted across the output terminals of the transformer to provide an AC voltage signal. The output depends both on the number of turns & the resistor, which allows the sensor design to be optimised for performance. Different models cover a range from 1 Amp to 3000 Amp. Output level of 1V is common but can vary from 100mV to 10V.
These are recommended for new designs.
5. Clamp-on Current Transducer
With a DC voltage output.
A self-powered transducer is built into the device. A range of different models is available with a 1Vdc output from 25 Amps. Higher voltage outputs are available up to 5Vdc but suffer from accuracy degradation at lower currents.
Applications include data loggers and SCADA outstations where current trends are being monitored.
