This article looked at how insert mounting errors affect the cutting tool performance in the face milling of 1.0503 steel. This study was conducted for 490-050Q22-08M inserts mounted in a Sandvik Coromant 490-050Q22-08M CoroMill cutter attached to an AVIA VMC 800 vertical milling center. A 3D geometrical model of the cutter was developed to determine the engagement of the particular inserts in the material removal process at different feeds per tooth. The test results showed that, at feeds ranging from 0.02 mm/tooth to 0.06 mm/tooth, only three out of five inserts took part in the face milling process, while at feeds higher than 0.12 mm/tooth, all the inserts mounted in the cutter body were engaged. The relative displacements in the tool-workpiece system were measured along the axis of rotation of the tool using a Renishaw XL-80 laser interferometer. The vibration signals recorded during cutting confirmed that there was a clear relationship between the number of inserts engaged in the process and the root mean square, the arithmetic mean, and the DC component. Multiple 2D scans of the face milled surface to measure parameters Ra and Rt helped determine the feed range where the cutting process was stable. The conducted studies allowed for the identification of optimal operating ranges for a tool with parameterized errors in the mounting of inserts within the tool body. The influence of these mounting errors, in correlation with the feed per tooth, on the surface roughness of 1.0503 steel was presented and compared with five other materials.

Speed feedback is indispensable not only for closed-loop controlled induction motors (IM) but also for the state monitoring systems of open-loop controlled IMs. Replacing speed sensors with speed estimations has many advantages including, e.g., hardware complexity reduction, sensor cabling elimination, and reduction of IM drive costs. From the various methods for IM speed estimation proposed in the literature, the model reference adaptive system (MRAS)-based speed estimator stands out because of its straightforward synthesis technique and lower computational complexity. On the other hand, this estimator is inherently sensitive to mismatching of IM equivalent circuit parameters. During transients, when the slip frequency cannot be temporarily controlled over the assumed operating point, rotor impedance varies with the slip frequency changes. This phenomenon is even more significant for open-loop controlled high-slip IMs (NEMA design D IMs), which operate under the cycling load like in, e.g., oil well pumps. The rate and the range of rotor impedance variability are related to the rate and the range of the slip frequency changes. Therefore, a speed estimator capable of modelling the slip frequency dependent variability of the rotor impedance may be required, particularly for the state monitoring systems of open-loop controlled IMs. This paper presents an MRAS-based speed estimator developed on the IM space vector model with the rotor impedance variability modelled by the parallel connected branches of the series rotor equivalent resistance and leakage inductance. The experimental test results confirm the precise speed estimation of the tested IMs achieved by the devised MRAS-based speed estimator in the considered slip frequency range and indicate its potential industrial application.

Rectifiers consisting of parallel connected 6-pulse bridges with modulation in DC current circuit show properties of multipulse rectifiers. A load unbalance of the component bridges of 12-pulse rectifier approximates the space vector to the case of rotating one. In consequence the shape of the line currents is close to sinusoidal one. In this paper the topology of multi-pulse rectifier with modulation in DC current circuit is presented. The simulation results of investigations were obtained by means of the space vector for control of modulators. The laboratory results of investigations of 2 kVA power for 12 - and multi-pulse inverters have been presented.

The variability of electromagnetic parameters of induction motors with deep-bar cage or solid rotors is represented, with a satisfactory approximation, by the machine secondary multi-loop equivalent circuit with constant lumped parameters. An estimation procedure of electromagnetic parameters of such an equivalent circuit is presented in the paper. The procedure is carried out using the measured frequency characteristic determined on the basis of instantaneous values of investigated induction motor electromechanical quantities. The study has been subjected to an induction motor with a solid rotor manufactured from the magnetic material, i.e. a machine characterized by a significant skin effect occurring in rotor solid conductive elements.

During torque transients, rotor electromagnetic parameters of an induction motor (IM) vary due to the rotor deep-bar effect. The accurate representation of rotor electromagnetic parameter variability by an adopted IM mathematical model is crucial for a precise estimation of the rotor flux space vector. An imprecise estimation of the rotor flux phase angle leads to incorrect decoupling of electromagnetic torque control and rotor flux amplitude regulation which in turn, causes deterioration in field-oriented control of IM drives. Variability of rotor electromagnetic parameters resulting from the rotor deep-bar effect can be modeled by the IM mathematical model with rotor multi-loop representation. This paper presents a study leading to define the unique rotor flux space vector on the basis of the IM mathematical model with rotor two-terminal network representation. The novel rotor flux estimation scheme was validated with the laboratory test bench employing the IM of type Sg 132S-4 with two variants of rotor construction: a squirrel-cage rotor and a solid rotor manufactured from magnetic material S235JR. The accuracy verification of the rotor flux estimation was performed in a slip frequency range corresponding to the IM load adjustment range up to 1.30 of the stator rated current. This study proved the correct operation of the developed rotor flux estimation scheme and its robustness against electromagnetic parameter variability resulting from the rotor deep-bar effect in the considered slip frequency range.