A method to detect a decrease of the demagnetization of permanent magnets of the generator of a wind turbine, wherein a frequency converter is able to adapt to the variable frequency of the generator output voltage to the frequency of a power grid, wherein the AC/DC converter or the DC/AC converter of the frequency converter is been disabled, the electrical connections between the generator and the frequency converter are switched on via circuit breakers, the generator speed is determined; the generator output voltage is determined by a voltage sensor which is part of the frequency converter,

the magnetic flux density of the generator is calculated depending on the generator speed and the generator output voltage, a demagnetization event is determined by comparing the resulting flux density value with a predetermined flux density value is provided.

A method to detect a decrease of the demagnetization of permanent magnets of the generator of a wind turbine, wherein a frequency converter is able to adapt to the variable frequency of the generator output voltage to the frequency of a power grid, wherein the AC/DC converter or the DC/AC converter of the frequency converter is been disabled, the electrical connections between the generator and the frequency converter are switched on via circuit breakers, the generator speed is determined; the generator output voltage is determined by a voltage sensor which is part of the frequency converter,

the magnetic flux density of the generator is calculated depending on the generator speed and the generator output voltage, a demagnetization event is determined by comparing the resulting flux density value with a predetermined flux density value is provided.

A prestored database indicating a correspondence of (depth)/HcJ (coercivity increment) and a prestored database indicating information of Dy diffusion condition (diffusion coefficient, diffusion flux and processing time regarding Dy diffusion) are used to compute distribution of Dy introduction amount in a magnet from shape information of the magnet and information of a Dy introduction face and compute distribution of HcJ in the magnet from the distribution of Dy introduction amount. Regarding a magnet having a coercivity that is distributed non-uniformly, a J/H curve is computed using the computed distribution of HcJ, and a demagnetizing factor at a predetermined temperature is computed using a temperature coefficient.

A prestored database indicating a correspondence of (depth)/HcJ (coercivity increment) and a prestored database indicating information of Dy diffusion condition (diffusion coefficient, diffusion flux and processing time regarding Dy diffusion) are used to compute distribution of Dy introduction amount in a magnet from shape information of the magnet and information of a Dy introduction face and compute distribution of HcJ in the magnet from the distribution of Dy introduction amount. Regarding a magnet having a coercivity that is distributed non-uniformly, a J/H curve is computed using the computed distribution of HcJ, and a demagnetizing factor at a predetermined temperature is computed using a temperature coefficient.

Embodiments include methods (and related systems, devices, and apparatuses) for determining a sorption separation factor for a binary gas mixture by applying a magnetic field to at least a portion of a sorbent (604) disposed in a chamber of a magnetic susceptibility device; directing a first gas stream including a first gas compound into the chamber at a first pressure and temperature to obtain a first magnetic susceptibility measurement; directing a second gas stream including a second gas compound into the chamber at a second pressure and temperature to obtain a second magnetic susceptibility measurement; directing a binary gas mixture including the first gas compound and the second gas compound into the chamber at a third pressure and temperature to obtain a third magnetic susceptibility measurement; and determining a sorption separation factor based on the first, the second, and the third magnetic susceptibility measurements.

Embodiments include methods (and related systems, devices, and apparatuses) for determining a sorption separation factor for a binary gas mixture by applying a magnetic field to at least a portion of a sorbent (604) disposed in a chamber of a magnetic susceptibility device; directing a first gas stream including a first gas compound into the chamber at a first pressure and temperature to obtain a first magnetic susceptibility measurement; directing a second gas stream including a second gas compound into the chamber at a second pressure and temperature to obtain a second magnetic susceptibility measurement; directing a binary gas mixture including the first gas compound and the second gas compound into the chamber at a third pressure and temperature to obtain a third magnetic susceptibility measurement; and determining a sorption separation factor based on the first, the second, and the third magnetic susceptibility measurements.

A device for measuring magnetic susceptibility of an object. The device includes a probe including a signal transmission line formed therein with the object being disposed in proximity to or in contact with the signal transmission line and a magnetization easy axis direction of the object being orthogonal to the signal transmission line, a first unit for applying a magnetic field in the magnetization easy axis direction of the object, a second unit for applying a magnetic field in a magnetization hard axis direction orthogonal to the magnetization easy axis direction of the object, a signal measurement device for measuring a signal transmitting through the signal transmission line in a state in which magnetic fields are applied by both the first unit and the second unit, and an arithmetic processing means for obtaining the magnetic susceptibility of the object based on the signal measured by the signal measurement device.

A device for measuring magnetic susceptibility of an object. The device includes a probe including a signal transmission line formed therein with the object being disposed in proximity to or in contact with the signal transmission line and a magnetization easy axis direction of the object being orthogonal to the signal transmission line, a first unit for applying a magnetic field in the magnetization easy axis direction of the object, a second unit for applying a magnetic field in a magnetization hard axis direction orthogonal to the magnetization easy axis direction of the object, a signal measurement device for measuring a signal transmitting through the signal transmission line in a state in which magnetic fields are applied by both the first unit and the second unit, and an arithmetic processing means for obtaining the magnetic susceptibility of the object based on the signal measured by the signal measurement device.

A sensor apparatus for determining and/or monitoring a process variable of a medium in a containment includes: a crystal body including at least one defect; a magnetic field system for producing a magnetic field in the region of the crystal body and in the region of the medium within the containment, wherein the crystal body and the magnetic field system are arrangeable from the outside at a wall of the containment; a detection unit for detecting a magnetic field-dependent, fluorescent signal from the crystal body, wherein the detection unit has an excitation unit for optical exciting of the defect and a detector for detecting the fluorescent signal; and an evaluation unit for ascertaining at least one piece of information concerning the process variable based on the fluorescent signal.

A method of diagnosing internal characteristics of a device includes applying a strong magnetic field to the device. The method can include reducing the strong magnetic field at a location of one or more sensors. At least one of the one or more sensors is proximate to the device. The method can include measuring induced magnetic fields around the device. The method can include measuring induced or intrinsic electrical current flow. The method can include measuring intrinsic magnetic properties. The induced magnetic fields can include diagnostic information on properties of the device and how the properties change over time. The device may be, for example, a battery, a capacitor, a supercapacitor, or a fuel cell. The presented measurement of magnetic susceptibility can be performed on materials, solutions, chemical substances, or tissue samples.