What is a Current Transducer?

Posted on Monday May 01, 2023 at 09:30AM  

A current transducer is a device that converts alternating or direct electrical signals into a proportional industrial standard electrical signal. When the current, voltage, power, or frequency flows into the transducer, the transducer changes it into an analog signal that can then be sent to a terminal or control system and be used for a variety of functions.

This conversion process relies on an induction principle. An electromagnetic field is created from the input current. The transducer senses and measures this input current. Then it converts the input current into a small output signal that is later converted into the standard electrical signal.

Current transducers come in a range of sizes and measurements. Some transducers can measure inputs as small as 0-50 amps while others can sense 0-200 amps. Current transducers can be found in numerous products, from refrigerators to electrical meters — just to name a few.

What Does a Current Transducer Do?

A current transducer reads current and generates a signal for its output. In this case, current is sensed and converted (transduced) into a proportional output (milli-amp or voltage). Output types include: 4 – 20mA, 0 – 5Vdc, 0 – 10Vdc, 1Vac, or 0.333Vac. The output range can then be interpreted by software to produce a current reading.

How Does a Current Transducer Work?

A current transducer is made up of 4 specific parts: a round, open sensor (sensitive component), a conversion component, a conversion circuit, and a power circuit.

A process wire that carries the input current is passed through the middle of the sensor or sensitive component as an electromagnetic field is created. The sensitive component detects the electromagnetic field and measures the electrical parameters as it creates the appropriate signal. This signal is sent to the conversion component which changes the signal to a small current signal that is sent to the conversion circuit. The conversion circuit processes and converts the current signal into electrical output that is sent from the transducer to connected devices.

Current Transducer Applications

Current transducers can provide numerous functions, so they are found in a wide variety of devices, systems, and industries. In addition to sensing, quantifying, and converting electrical current from one type to another, these devices can also help track motor control, fan/pump status, and load trending. Here are some applications where you may find a current transducer improving facility management.

  • Electrical meters: An electrical meter on a home or commercial building measures the large amounts of electricity sent from the power grid or substation that is sent into the building's electrical panel. It shows how much load that the building's systems are using as these measurements can be read by a utility company.
  • Machining equipment: Machining equipment used in workshops, such as CNC milling, grinding, and router machines, use current transducers to convert the incoming voltage. This conversion process is used to monitor the machine when it is in use or when it is idle.
  • Pump systems: Pumping systems contain drive motors that need to operate efficiently. To detect issues, a current transducer measures the motor's current draw. If there is a drop in the current used by the motor, a signal can be sent to the PLC or other control device to give an alert regarding the issue. The current transducer may also act as a switch to turn off the motor.

What's the Difference Between Current Sensors and Current Transducers?

Current Sensors (CS) and Current Transducers (CTs) are used to monitor the current flowing through an electrical conductor. They generate the information needed for status and metering applications. Though people tend to use the terms ‘current sensor’ and ‘CT’ interchangeably, there are some more than subtle differences between the two terms.

Current sensors are simple devices that only sense the incoming current and measure it. They do not offer additional functions. Instead, the sensors relay this information to other devices that the sensor is connected to so that those devices perform a specific function.

Current transducers have additional components, including sensors, which offer more flexibility on what the transducer can be used for in the application. It can be used as a control switch, load measurement device, and a health or safety monitor for devices.

Veris offers a variety of current sensors, current transducers, and current transformers in both split-core and solid-core options. To learn more about our current sensing products, visit our website or call to speak with our sales team at 1-800-354-8556 or +1 503.598.4564.

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