The paper deals with the accurate slip measurement of induction motors. The proposed procedure uses a non-invasive slip measurement scheme based on digital filtering and dynamic parameter estimation. The slip measurement is carried out without speed sensor and is deduced analyzing the magnetic field harmonics spectrum in proximity of the induction motor. First the emf induced waveform, taken from a searching coil, is filtered using algorithms based on the discrete Fourier transform. Then the stator frequency and rotor frequency are obtained by comparing the filtered voltage with a mathematical model using an optimization procedure. The model's parameters are varied until an adequate match is obtained with the filtered voltage. Experimental results are presented to validate this method.

If the rotational symmetry of single mode (S.M.) fiber is disturbed, either during manufacturing or through some external perturbation the polarization modes have different propagation constant. Due to this generated birefringence, the linear polarized light through S.M. fiber is distributed in two orthogonal eigenmodes. As a result, the state of polarization (SOP) is changed at the exit end of the fiber. In the present paper, electro-optic effect on S.M. fiber has been induced by placing the fiber coil under electric field. Investigation shows that the developed birefringence in fiber arises mainly due to bending and electrostriction/Kerr effect. So, by varying the electric field, the developed anisotropy or birefringence ultimately can be utilized to control the state of polarization (SOP) at the output. Experimental study has been carried out on 40m. and 48m. coiled fiber under D.C. voltage (0 to 280 volts). Results show that SOP of two prototype polarization controllers, become circular i.e. λ/4 plate at 235 volts and 143 volts respectively. The external effect acting upon SM fiber is directly calibrated with respect to phase and ellipticity of light. The correction in calibration equation in particular case where ellipticity change is considerable, has been reported in the present paper. Experiment has been performed to verify the theoretical studies and error has been computed.

An advanced and novel numerical method for analysis of combined instrument transformer will be given in this paper. The three-dimensional magnetic field analysis results by using the finite element method will be used for estimation of the metrological characteristics of the transformer. The analytical and the results derived by the original FEM-3D program package will be compared and discussed. This will enable further optimal design of the instrument transformer prototype by taking into consideration the exact mutual electromagnetic influence of both transformation cores (current and voltage measurement magnetic cores) and by using stochastic optimisation techniques.

The paper describes a precision measurement system developed at NML for the calibration of three-phase instruments measuring harmonics of current up to 16 A, voltage fluctuation and flicker. Particular attention is given to establishing a traceable link to the Australian primary standards of electrical quantities. Current and voltage harmonics up to the 99^th and fluctuating voltages can be generated and measured with relative uncertainties close to 1·10^-5.

A new crosstalk model between two twisted pairs when a mismatch of the wire pairs extremities exist, is proposed. The crosstalk model allows to predict the PSD at the near-end and far-end of the victim line if the PSD of the disturber is known. The model takes any mismatch into account which exists when a line is not terminated with its characteristic impedance. Using the same unbalance assumptions as other authors used with success in the past, analytical expressions are given to calculate the crosstalk.