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Shayak Bhattacharjee

Publications and source records attributed to Shayak Bhattacharjee.

9 recordsLinked to original sources
arXiv2015

Minimizing Wheel Slip in Railway Locomotives with Coupled Permanent Magnet Synchronous Motors

In this work I consider control strategies of permanent magnet synchronous motors in which the back-emf signal from the motor is used to achieve commutation of the six step driving circuit. I show that if the strategy is modified to connect multiple motors in a cyclic chain, then a collective synchronized state is favoured. The stability of this state can be exploited in the bogies of a railway locomotive to automatically terminate wheel slipping episodes.

nlin.CD↗
arXiv2014

Another classical analog of Grover's quantum search

In this work I describe a classical analog of Grover's quantum searching algorithm, explaining why a quantum algorithm should be able to perform search in O(sqrtN) steps and also acting as a useful pedagogic demonstration.

quant-ph↗
arXiv2014

Iterative Solution of Maxwell's Equations for an Induction Motor

In this work we use classical electromagnetism to analyse a three-phase induction motor. We first cast the motor as a boundary value problem involving two phenomenological time-constants. These are derived from the widely used equivalent circuit model of the induction motor. We then use an iterative procedure to evaluate these constants and obtain the motor performance equations. Our results depend only on the geometrical parameters of the motor and can be used to derive precise expressions for the excitation frequency and applied voltage needed to extract maximum performance from a given motor at any rotation speed.

physics.gen-ph↗
arXiv2013

Synchronous motion in a devil's stick -- variation on a theme by Kapitza

The counter-intuitive rotational motion of the propeller of a devil's stick when the agitator is rubbed against the pylon has long intrigued performers, audiences and scientists. The apparently unrelated phenomenon of self-stabilization of a Kapitza pendulum at the inverted position, once again an amazing lecture demonstration, has on the other hand been subjected to years of investigation and research. Here we show that the two systems are in fact identical, and obtain a previously unreported, friction-stabilized synchronously rotating state in the Kapitza pendulum, which in fact explains the rotational motion of the Devil's stick.

nlin.CD↗
arXiv2012

Fan affinity laws from a collision model

The performance of a fan is usually estimated from hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this work we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour of air is incorporated. Our calculations prove the affinity laws and provide numerical estimates of the air delivery, thrust and drag on a rotating fan.

physics.class-ph↗
arXiv2011

Bohr Sommerfeld quantisation and molecular potentials

We use the Bohr Sommerfeld quantization rule along with a perturbative evaluation of the action intergral to find exact energy levels for the Pöschl-Teller potential (both hyperbolic and trigonometric forms), the Morse potential, and the Rosen Morse potential. Combining perturbation theory with the simplest asymptotic evaluation of the action integral allows us to obtain all the energy levels of the Lennard-Jones potential with an accuracy greater than 0.1 per cent and serves to confirm that the perturbation results for Pöschl-Teller and Morse Potentials are exact.

math-ph↗
arXiv2011

Analysis of a Three Phase Induction Motor Directly from Maxwell's Equations

The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This allows us to estimate the torque developed by a motor without knowing the details of its circuitry.

physics.class-ph↗