Definition of a Current Probe
A current probe is an electrical device that measures and quantifies the number of amperes that flow or pass through a conductor. Also known as a current clamp or a current meter, the instrument finds application in computing the alternating current (AC) operating in a conducting device. It also assesses and determines the waveform and phase. A few unique types and models of current probes can also calculate the direct current (DC) passing through the conductors.
A current probe comes with jaws that wound or clamp around the conducting material to take the readings during the measurement process. The conductors may consist of pipes, wires, electrical appliances, and so on. They may belong to various fields, domains, and industries in the residential, commercial, and manufacturing sectors. Due to these clamps, the device works without physical contact with the current-conducting materials at any point.
What is a Coreless Clamp-on Current Probe?
As the name suggests, a coreless clamp-on current probe is a current clamp that does not have an integrated core inside it. They are similar to a flexible version of a Rogowski coil current meter but differ in a few ways.
A coreless clamp-on probe uses an array of numerous sensors to operate and proffer its functions instead of a core. They help examine the magnetic field that the current that passes through the conductor generates at various points.
It aids in the measurement of the magnitude of the total magnetic field and the output signal. It is because the latter parameter is proportional to the flowing current.
Working Principle of a Coreless Clamp-on Current Clamp
Like all other current clamps, a coreless clamp-on current probe works on the principle of electromagnetic induction. The postulate states that when current flows through a conductor, a magnetic flux gets generated in it. Subsequently, it creates a magnetic field. A coreless current probe comes with multiple magnetic field sensors that spread around the perimeter of the instrument.
Each of the magnetic field sensors measures the magnitude of the magnetic field that the current-carrying conductor generates. The total sum of the strength of all of them helps estimate the voltage signal at the output.
Benefits of a Coreless Clamp-on Current Probe
A coreless current probe has and proffers numerous benefits that aid significantly in measuring the current flowing through a conductor. A few advantages of this electrical instrument comprise the following:
- Due to the absence of a core, a coreless current probe is lightweight. It has a narrower cross-sectional area.
- The device can recover from current overload almost instantly and does not suffer from or experience any magnetic hysteresis.
- There is no need to saturate the core, and hence, the instrument does not sustain much damage and lasts for a long time.
- A coreless clamp-on current probe can tolerate and work in harsh conditions and environments having high noise and electrical disturbance levels.
- The instrument uses the no-contact clamping feature to operate without cutting off the live power supply to the conductors.
- The ergonomic design of coreless current clamps allows it to fit into the palms and hand seamlessly. It stands true even with protective gears on.
- The instrument can replace a multimeter if cutting off the power supply can lead to safety concerns and hazards.
- The lightweight nature permits users to carry and store the current probe in a toolbox effortlessly. During use, it does not exert any pressure or strain on the hands.
- The electrical device has a compact footprint that allows it to take the current measurements of high accuracy even in narrow and constricted areas.
- The instrument proffers a broad range of estimations and computations in a short period, curbing excessive wastage of effort and money.
Drawbacks of a Coreless Clamp-on Current Probe
All instruments have their fair share of disadvantages as they have their advantages. Some of them entail the following drawbacks:
- Due to the absence of a magnetic core, the coreless clamp-on current clamp can measure current in comparatively smaller quantities. It may be because the resistance and heat generation values are higher than a current clamp with a core.
- The instrument may proffer a low response speed because the frequency band gets narrowed to provide high levels of resolution.
- It is arduous to acquire a high accuracy of measurement. It is because the hall element offset amplifies when the correction IC gain gets increased.
What to Consider When Buying a Coreless Clamp-on Current Probe?
A buyer must consider several parameters and factors with scrutiny during the purchase of a coreless clamp-on current probe. They ensure that the final choice of the electrical instrument does not end up being in vain.
They must answer the following questions to check which coreless current clamp and features suit their needs the best. A few of them include the following queries:
- What is the parameter (alternating or direct current) that needs to get measured?
Some coreless clamp-on current probes measure either alternating or direct current. A few other types estimate both.
- What is the maximum and minimum value of the current that needs quantification?
Depending on the required accuracy of quantification, the current values should vary.
If a higher range of accuracy is required, a higher current value is better and vice versa.
- What is the size of the conductor where the coreless clamp-on current probe will get clamped?
The conductor size determines the dimensions of the coreless current meter’s jaw that clamps it.
- What type of current probe output does the buyer need to work with (mV, DC, mA, AC, etc.)?
The user or the buyer of the coreless current probe needs to check the maximum value of the receiver impedance. It ensures that the instrument performs according to the required specifications.
Some other questions that the buyer can raise comprise:
- What kind of output termination is required?
- What is the value of the working voltage of the conductor that needs to get measured?
- Will the current probe get used for power measurements or harmonics?