A device for measuring current strength: what is the name and classification, principle of operation and scope of application, choice

In the 19th century, a special electrical measuring device was invented, which serves to record the strength of alternating and direct current in the network. The currently improved device for measuring current strength is called an ammeter. The device is connected to the circuit according to a strict sequential scheme.

Principle of operation and scope

The unique structure of the device allows it to function according to a simple communication scheme. Together with a permanent magnet, a steel armature and an arrow fixed to it are located on the bracket axis. When exposed to the armature, permanent magnets transfer their properties to it. In this case, the position of the armature is located along the line of force passing near the magnet.

Such an anchor position sets the zero point of the arrow on a graduated scale. Magnetic flux occurs when current from a generator or similar source flows through the bus. A right angle is maintained between the lines of force of the magnet and the point where the anchor is located. The force level of interaction of flows will depend on the magnitude and direction of the electric current flowing through the bus. It is by this indicator that the arrow of the device deviates from zero.

Analog and digital devices are used in many sectors of the national economy and industry. The most active operation is carried out at large enterprises that are associated with the distribution and recovery of thermal and electrical energy.

The unit is widely used in the following industries:

1. radio electronics;
2. electrical engineering;
3. energy branch of the industry;
4. construction;
5. transport networks;
6. research laboratories.

The device is used not only in large enterprises, but also in everyday life. It is useful to have an ammeter in your personal vehicle. It will help to quickly identify malfunctions of electrical equipment, even on the road.

Classification of measuring instruments

The division of ammeters into two large groups is accepted: digital and analog models. The latter have a unique gradation of their own:

1. Electrodynamic model. Reacts actively to the interactions of the current field flowing through the coils. One of the coils can move freely, while the other is fixed. The high demand for the product is due to its low price and excellent performance. It can often be found in scientific laboratories.
2. Ferrodynamic. Possesses maximum accuracy and efficiency of use. A device with such a mechanism does not react to extraneous sources of magnetic fields. In addition to the ferromagnetic closed wire, the core and the coil are fixed in the housing. Models of this type are slightly more expensive than their counterparts.
3. Electromagnetic type. The device is the most simple in its content, it is not equipped with a floating winding with a core. Depending on the power of the current, the core, fixed with an arrow, moves to the side, clearly indicating the digital display of the measurement.
4. Magnetoelectric mechanism. Was invented by one of the first. The principle of operation is based on measuring the level of interaction between the magnetic field and a fixed coil. This type is characterized by the minimum power consumption, which allows for a minimum coefficient of rejection and a sufficient level of sensitivity. The division scale is uniform, the same distance is maintained between each of the marks.

By the type of reading device, ammeters with a writing mechanism, electronic equipment, with light and pointer indicators are distinguished.

Operation of the device

A device that is simple in its internal structure requires compliance with a number of operating rules:

1. The technique is whimsical to storage conditions. For all mechanical and analogue products, strong shaking, impacts, falling are unacceptable. Any adverse effect can lead to inaccuracies in operation.
2. The shunt used must be slightly lower than the current being measured. Special nuts will help to fix it.
3. At the time of connection, ensure that there is no current supply to the device under test.
4. An important point is checking the polarities.
5. The device will burn out when connected to the mains without supplying a load.
6. It is strictly forbidden to touch the bare wires with any unprotected parts of the body.
7. Every 6 months it is recommended to check the equipment in the Gosstandart authorities.

An ammeter requires a series connection in an electrical circuit with a load. For high currents, a transformer, shunt, magnetic amplifier and millivoltmeter are used. From the standard range, the primary currents of the shunts can be selected, provided that the secondary voltage is standardized in the region of 75 mV. At high voltages with a mark of more than 1000 V, galvanic isolation of ammeters is used in the AC circuit, and special magnetic amplifiers are used in the DC circuit.

Selection rules

The modern market for goods and services offers the consumer a huge number of ammeter models. The basic rules will help you choose a device for measuring current:

1. The most accurate measurements will be given by a device with an average resistance of up to 0.5 Ohm.
2. The contact clamps must be coated with a special anti-corrosion compound.
3. The basis of high-quality technology is a sealed housing without damage. Preventing moisture penetration will not only maximize service life, but will also improve the accuracy of the readings.
4. The type of unit depends entirely on the purpose of its use.
5. Connect to a variety of sources for research with a compact, portable device.
6. There is a modular type of ammeter, designed for installation in a seat in the power panel.

To study the current strength, scientists created an ammeter. Due to the low internal resistance, this measuring device does not affect the parameters of the current in the measured circuit. The device has found wide application in the large network industry, in everyday life and in the household.