The segment of electrical measuring instruments is undergoing revolutionary changes associated with the transition to the digital principle of data processing and the tendency to combine several functions in one device. At the same time, traditional approaches to the development of this equipment remain in demand. This niche still includes a mechanical ammeter. What it is? This is a device that measures current in its various states. This is not to say that this device does not affect the mode of transition to an electronic basis, but mechanical models are still indispensable in many industries.
Instrument Overview
The ammeter is used in many areas where, in one way or another, activity is associated with electric current. For example, its function can be used in a car repair shop when repairing electrical wiring, when organizing the operation of substations, in construction when performing electrical installation works, etc. In factories, there is a need for constant monitoring of technological processes supported by electric energy. Ammeters are also used in this case. What is it from the point of view of the average user? Is this appliance needed by the general consumer? Of course, it is advisable to carry out any electrical operations during repair work or when installing a conventional lamp under the control of a measuring device, the main of which in this niche will be an ammeter. Another thing is that in everyday life simplified versions of the device are used, deprived of many functions that experts use.
Ammeter device
The design of the device is designed for series connection in an electric circuit. To reflect the readings in classic ammeters, a scale with an arrow is used. In order to expand the measurement limits, some models provide the ability to connect to the circuit through a transformer or shunt. The fluctuations of the arrow in the measurement processes are determined by the resistance of the ammeter, which occurs when the current passes through the built-in electromagnetic coil. The angle of the arrow is proportional to the measured current. Thus, the current strength is fixed, which at the time of measurement acts on the device. Passing through the coil, the current creates a kind of torque on it, the activity of which is reflected in the behavior of the arrow.
Varieties of ammeter
At the moment, there are several versions of the ammeter, each of which has its own design features and some differences in the principle of operation. The most common can be represented as follows:
- Magnetoelectric. The traditional model of the device, reflecting the basic principle of interaction of a moving coil and a magnetic field. Such devices are characterized by energy efficiency and high sensitivity, which makes it possible to apply a uniform scale to them with relatively accurate measurements. The disadvantages of this ammeter are reduced to a complex technical device and limitations in its operation, since application is possible only in direct current conditions.
- Electromagnetic The design of the device also includes a coil through which current must pass, and with it ammeter cores are used. What is it in terms of operational value? A device with such a filling is quite versatile, since it can work both on alternating and direct current. Also, its advantages include ergonomic control and compactness. But on the other hand, users note its low sensitivity and unsatisfactory measurement accuracy.
- Electrodynamic. The principle of operation of this apparatus is based on the interaction of magnetic fields passing through two coils - mobile and motionless. As a result, when measuring, you can rely on the reliability of the readings, but you also need to be wary of third-party interference, which in principle will make it impossible to operate this device.
Features of a digital ammeter
Such models are almost devoid of mechanical parts in the filling. Accordingly, the disadvantages of pointer ammeters are also eliminated, among which the impossibility of accurate readings in conditions of strong vibrations can be called. Digital devices can be used both vertically and horizontally. Thanks to the electronic basis, the readings themselves can be processed, converted and stored for short-term or long-term statistics in the device memory. Moreover, the latest generation digital ammeter has opened up opportunities for automatic operation, in which the device takes readings in predetermined modes without operator intervention.
Instrument Operation
The device is introduced into the electric circuit in series with the load, and under high current conditions - through a transformer, shunt or magnetic amplifier. Together with an ammeter, calibrated shunts and millivoltmeters can also be used to comprehensively measure different current parameters. At a minimum, the combined use of this measurement technique gives more accurate research results. It is also necessary to take into account the limitations on measuring the strength of the ammeter, which in conventional models fall within the range of 30-100 A. Beyond these limits, the use of a kiloammeter.
Conclusion
From the point of view of general electrical engineering, an ampere is an elementary unit of measurement that is used to reflect the characteristics of various devices and electronic devices. Differences in the means of measuring this value are rather determined by the operating conditions of the ammeter. What is the idea of an electrician? A standard tool that can be made in the form of current clamps. This is not even so much a means of measurement as a mounting device for indirect verification of current readings. The situation is different with ammeters that are used in the laboratory. In this case, we can talk about stationary equipment with powerful electronics, capable of processing current parameters under conditions of high accuracy, regardless of its source.