The natural magnetic field overcomes great distances, it can pass through the rocks, buildings and also organisms. It can be used for the navigation, object security, or archaeology. The technical magnetic fields are created by the acting of the electric current. They can be used for the diagnostics of the machines, processes, material research, or demagnetization. The useful information is carried by the magnetic field in the area of stationary but also low-frequency magnetic phenomena. Their measurement and analysis allow us to obtain this information and to use it in the process of control, diagnostics, or survey.

From this moment, its development has begun. Nowadays it applied in the VEMA magnetometers. More than 30 years of our own research and development of various sensory systems and of the work with the measuring devices are a guarantee of our experience that allows us to design a tailor-made solution for the customer’s needs. In addition to our own measurement systems, we can implement the modernization of your measurement chains, or we can supplement them with the measurement of other physical quantities. Our experience with both – digital and analog technology, allows us to create a solution for the cases where no typical commercial solutions can be applied. You can find our implementations from the coal mines, through the engineering industry, the production of the medical aids, to the satellites.

Today, satellites weighing from one to twenty kilograms have been creating a new segment of the space exploration. Most of them are placed in the low orbits at the altitudes from 300 to 500 km. Magnetism is used also on their boards. It is a source of information about the magnetic course for the determination of the satellite’s position, and it is also a source of the torque for the stabilization of its rotation. We materialized our many years of experience in the field of magnetism during the mission of the first Slovak skCUBE satellite. We calibrated the on-board magnetometers of this satellite using the method based on the neural networks, and we also participated in the development and production of the satellite’s electromagnetic actuators, which successfully stopped the initial rotation of the satellite after it was placed in the Earth’s orbit.

The first step before deploying any measuring component is its calibration. We have developed several calibration procedures for our sensor systems, including fixtures and reference signal generators. We mainly focus on the calibration of inertial sensors, namely magnetometers, accelerometers, and gyroscopes. For our customers, we can provide unofficial calibrations of their measurement systems, as well as to give them advice about the creating of the measurement procedures within the internal product quality control systems or process control.

Currently, several physical principles have been used and one of them is based on the magnetometry. Special measuring systems have been used in the various versions, from the single-channel, hand-carried magnetometers intended for the manual operation, to the multi-channel systems towed behind a vehicle or carried by a flying vehicle just above the Earth’s surface. Our versatile VEMA magnetometer is also sensitive enough to be used for the archeological survey purposes. The probes of the particular measurement channels can be aligned into the gradient arrangement, which will increase the sensitivity of the measurement to the local anomalies and will suppress the influence of the distant sources. This will enable the creation of the detailed map of the archaeological site before starting of the excavation works. Our magnetometer was practically verified in the conditions of the Nižná Myšľa site with the remains of the settlement from the Younger Bronze Age, as well as in the vicinity of the church located in the village. The measured anomalies were in correlation with the uncovered findings of the skeletal remains and small building parts.

These logistical elements reach lengths of several kilometers. Their fault-free operation is critical, especially in the conditions of their continuous operation. The conveyor belt damage caused by the foreign objects or by the breaking of the integrity of the glued joint can seriously endanger the operation of the entire technological section. Monitoring of the presence of the foreign objects in the transported material is the main application of our HFT sensor systems. These systems have been successfully used especially in the surface mines in the Czech Republic and in the Třinec Iron and Steel Works. Until now, more than 70 such systems have been installed operating either as the separate safety elements or as part of the complex systems in cooperation with the electromagnetic foreign object separators.
The KDP system can be considered as the complement, which enables the comprehensive diagnostics of the belt conveyor. This system monitors the individual joints of the belt to determine if there is any damage and at the same time it allows monitoring of any conveyor belt part to detect also minor damages, the spread of cracks or small cuts. The system also monitors the start-up and the run-down of the belt conveyor, it can monitor the propagation of the various waves along the belt conveyor, and thus it enables the entire assembly to be adjusted to a safe, balanced working mode.

This field is almost impossible to disturb or shield. The magnetic field passes through the building materials, subsoils, as well as thick steel structures. These properties can be used to protect the critical infrastructure objects or other objects with the required high level of protection. By the convenient placement of the magnetic field sensors and the consequent real-time data processing, it is possible to distinguish changes caused by the natural activity of the Earth’s magnetic field from the changes caused by the presence of a person, vehicle, or other technical equipment. The advantage is in the possibility of the hiding of the sensors into the structural elements of the rooms and buildings, under the surface of the floor or above the ceiling structure. The security system created in this way remains perfectly hidden. As the magnetic field is also created by the electric power distribution, such a system can also react to a power outage, as well as to an unexpected increase in the electricity consumption, which can signalize the emergence of a dangerous situation in the protected area. The VEMA magnetometer was tested as a security system, and the results of the measurements demonstrated the ability to detect the presence of a person in the protected area, as well as of the vehicle passing at a distance of several meters from the protected area.

For these purposes, many methods have been developed. They are based on the measurement of vibrations, noise, or local warming. An innovative approach of the technical diagnostics is based on the utilization of the magnetic field. All moving parts of the machines interact with the Earth’s magnetic field during their operation, or they create the local anomalies in the magnetic field. In the same way, all components powered by the electric current generate the electromagnetic fields, which carry information about the working mode and technical condition of this part of the device. The advantage of the magnetic field measurements is that the measurement can be contactless, directional and can be performed through the construction of the device itself. The practical measurements showed that the vibrodiagnostic measurements can be fully replaced by the magnetometry. Using the example of the magnetic field measurement of the small hydroelectric power plant with an installed output of 400 kW, we demonstrated the possibility of measurement not only of the state of the transmission system of the power plant, but also of the generator, of the turbine, and of the measure of the torsional oscillations of its shaft. Furthermore, the measurement could be performed during the full operation of the power plant, without the need for intervention or even physical contact with the turbine. Software processing of the measured data and the consequent post-processing allowed us to perform the diagnostics of the entire assembly, from the turbine blade wheel to the electric power generator, performing only one measurement. This innovative approach to the measurement makes it possible to significantly reduce the cost of the technical diagnostics, which would otherwise require shutdown and dismantling of the turbine covers in order to stick the strain gauge sensors and placement of the measuring electronics on the turbine shaft.