A hardware-based detection system includes, among other things, a signal-generating circuit for generating a signal which is functionally related to current in a motor winding, a reference current, and a duration of time. The system may also include a comparator circuit for comparing the generated signal to a reference signal, and for thereby detecting an over-temperature condition in the motor winding. If desired, a compensating circuit may be used to generate a variable reference signal as a function of ambient temperature. A method of operating a detection system is also disclosed. If desired, the detection system may be completely implemented in hardware using an uncomplicated analog circuit architecture.

A diagnostic device for diagnosing a faulty condition in a gradient amplifier system is presented. The diagnostic device includes a first current sensor configured to be coupled to an input terminal of a filter unit, where the first current sensor is configured to measure a first electric current at the input terminal of the filter unit, and where the first electric current includes a high frequency current component and a low frequency current component. Further, the diagnostic device includes a diagnostic unit coupled to the first current sensor and configured to determine an impedance across the filter unit and a load unit based on the low frequency current component of the measured first electric current and a pre-stored reference voltage, and diagnose the faulty condition of at least one component in at least one of the filter unit and the load unit based on a characteristic of the determined impedance.

A method for checking a control circuit for an inductive load, wherein one or two currents are measured and evaluated. An arrangement for carrying out such a method is also disclosed.

The condition monitoring system includes an acquisition unit and a generation unit. The acquisition unit acquires waveform data from a measuring device to measure an electrical signal that is either output or input of a converter. The waveform data represents a waveform of the electrical signal. The generation unit generates, based on the waveform data, analysis data to monitor the condition concerning the converter. The generation unit obtains, by frequency analysis, a plurality of combinations, each including a value of a frequency and a value of a feature quantity that is either intensity or phase, based on the waveform data when a value of the drive frequency varies and thereby generate the analysis data having at least three variables including the frequency, the feature quantity, and the drive frequency.

To provide a motor controller and a motor control method allowing inspection for checking the presence or absence of specification error in motor winding to be conducted more simply, efficiently, and with high accuracy. A voltage command value as a command value for driving control of a motor and an excitation frequency are sampled. An actual current flowing in the motor being driven under control is detected. Theoretical values of a voltage command value, a current, and an excitation frequency are determined from a parameter for driving the motor and a condition at the time of driving. The theoretical values of the voltage command value, the current, and the excitation frequency are compared with the values of the voltage command value, the current, and the excitation frequency respectively at the time of the driving, and it is determined that there is winding abnormality if differences between the comparable values exceed a threshold range set in advance.

A method (60) for determining resistances (R.sub.1, R.sub.2, R.sub.3, R.sub.N) on a voltage level of a multiphase transformer (10) comprising one winding (u, v, w; U, V, W) for each phase comprises injecting a particular first current into the particular winding (u, v, w; U, V, W); recording a particular first voltage caused by the injected first currents in the plurality of phases; injecting a particular second current into the particular winding (u, v, w; U, V, W), wherein the particular injected second current differs from the particular injected first current in at least one of the plurality of phases; recording a particular second voltage caused by the injected second currents in the plurality of phases, and determining the resistances (R.sub.1, R.sub.2, R.sub.3, R.sub.N) on the voltage level on the basis of the injected first and second currents and the recorded first and second voltages. An apparatus (70) for determining resistances (R.sub.1, R.sub.2, R.sub.3, R.sub.N) on a voltage level of a multiphase transformer (10) is also proposed.

The present disclosure relates to methods and devices for calculating winding currents at a delta side for a transformer. The transformer has two or more windings, with a first winding being a delta connected winding. The method may comprise obtaining line currents measured with measurement equipment associated with lines connected with the windings. The method may further comprise calculating zero sequence currents for at least a second winding, from the line currents of a corresponding line. The method may further comprise calculating zero sequence currents for the first winding, based on the zero sequence currents for at least the second winding, a phase displacement between the windings, and a turns ratio associated with the windings. The winding currents may be calculated from the zero sequence currents of the first winding, and the line currents of a corresponding line.

A temperature estimation device calculates a first estimation temperature of a reactor on the basis of a reference estimation temperature to which a first lag period is provided and outputs from a temperature change amount calculation unit to which a second lag period is provided, predicts a second temperature change amount of the reactor over a predetermined period on the basis of the first estimation temperature, and then predicts a second estimation temperature of the reactor.

A temperature estimation device calculates a first estimation temperature of a reactor on the basis of a reference estimation temperature to which a first lag period is provided and outputs from a temperature change amount calculation unit to which a second lag period is provided, predicts a second temperature change amount of the reactor over a predetermined period on the basis of the first estimation temperature, and then predicts a second estimation temperature of the reactor.

A method for determining a switching state of a valve, an inductance variable being determined on the basis of current and voltage measurements and the switching state being determined on the basis of the inductance variable. Also disclosed is a solenoid valve assembly for carrying out such a method.