When working with electricity, you cannot do without special devices and tools. Such devices include DC current clamps. They allow you to measure the voltage indicator without first breaking the circuit. While working with the tool, different techniques are used. Before choosing a suitable model, it is advisable to familiarize yourself with its technical characteristics, strengths and weaknesses.
Content
- The use of ticks
- Measurement methods
- Working with the tool
- Varieties of the device
- Additional functions
The use of ticks
Only electric clamps make it possible to measure the strength of direct or alternating current that flows through the conductors, without breaking the circuit itself. No other tool can handle this task. Such measurements are necessary to control the amount of electrical energy consumed by devices and installations without stopping their operation. During the procedure, you can perform the installation or repair of household equipment.
Due to this feature, the electric clamp is considered the second most popular tool for electricians after a multimeter.
The design of the unit includes the following elements:- a magnetic circuit in the form of pincers;
- button for its disclosure;
- measurement method switch;
- display;
- three sockets for different probes;
- button that fixes the results.
Measurement methods
The device has two types of sensitive elements, which are made on the basis of a special transformer. According to the type of analyzer, clamps are divided, which can measure both alternating and direct current, as well as only the second indicator.
The more common tool required when working with alternating current. This is due to its design and low cost. The device works on the principle of using the effect of transformer amplification. The measurement itself takes place in several stages:
- the conductor is led into a sliding magnetic circuit;
- the element will play the role of the primary winding of the transformer;
- the voltage at the output of the element will be measured as a function of the amount of alternating electricity passing through the conductor.
Another type of instrument is the DC current clamp - appeared after the discovery of the Hall effect. The voltage of the magnetic field inside the conductor changes, which contributes to the formation of potential at the measured point. In this case, the indicator is equal to the value of the flux applied to the semiconductor. Based on the effect, a sensor has been developed that exhibits sensitivity to direct and alternating magnetic fields. Such devices are fast acting, so it is easy to detect short surges of electricity with them.
Working with the tool
There are several ways to measure current with a clamp. The main parameters that are taken into account in this:
- electricity flowing through one conductor;
- current of several conductive materials;
- amplification of signals.
The most common way is to measure the current flowing through one material. A conductor is inserted into the pliers, placing its plane perpendicular to the instrument. It is necessary to set a suitable range of indicators on it, after which the resulting value will be displayed.
You can bring several conductors into the magnetic circuit at once. In this case, the current meter will show the difference value of the flowing electricity. For example, if you measure the simultaneous zero and phase indicators for a 220 V household network, then the instrument will show the current leakage in the load.
When it is necessary to find out the indicator of small quantities, it is recommended to apply an amplified signal to the sensor by winding the conductor on the magnetic circuit. But the real value of the flowing electricity will have to be calculated independently. To do this, divide the number shown by the tool by the number of turns of the conductor.
Varieties of the device
Depending on the functionality and parameters, there are several types of clamp meters. Basic tools:
- with pointer indication;
- with digital display;
- for connection to other measuring instruments;
- high voltage device.
The first devices in which transformer current measurement began to be used were the meter with dial gauge. During operation, you can change the number of windings on the secondary circuit. The device has a minimal cost, measurements are carried out with high accuracy. The disadvantage is the narrow frequency range. Ticks of this type are sensitive to mechanical damage. The slightest impact can reduce the accuracy of the work.
Modern devices have a built-in microcontroller system that processes signals. Thanks to it, the readings are easier to read, in addition, the calibration of the measuring range is used. Records of current values can remain in the memory of the device. The pliers are easy to use, but they have a significant drawback - the measurement accuracy drops when the shape of the electrical impulses differs from the sinusoid.
To expand the functionality of oscilloscopes and multimeters, devices that connect to them are used. The peculiarity of such instruments is the absence of any indication of the measured values. Clamps allow you to work with a current of almost any frequency, but for normal measurement you need to pick up an additional device that has a display or dial indicator.
It is necessary to use special tools for working with high voltage networks. Such current measuring devices have increased electrical insulation, which guarantees the safety of a specialist during work. Clamps allow you to monitor the current in substations and distribution centers. But it is possible to measure only alternating electricity of a narrow frequency range.
Additional functions
Many devices are universal, since their device already has an ADC (analog-to-digital converter), which is necessary to measure an analog signal. But some manufacturers add additional functions - the ability to measure temperature, resistance and voltage. Selected models combine the capabilities of an electric clamp and a multimeter or oscilloscope. Their cost is not much higher than the price of analogs, but it will be cheaper to purchase a multimeter separately.
Adapter pliers measure AC and DC current, but have no additional functions. Before choosing a suitable instrument, it is determined with the capabilities that it should have, measurement accuracy, frequency range and parameters.
This data is compared with the price, which will allow you to choose the best option, and then effectively use the current clamp.
