hw4 - produced and in what direction (clockwise or...

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EE321 Spring 09 Homework 4 Problem 16 – Calculation of Torque The flux-linkage of a certain rotational electromechanical device may be expressed i rm ) 4 sin 2 5 ( θ λ + = where rm is the rotor position and i is the current. What is the electromagnetic torque ? Problem 17 – Magnetic Linearity Is the following system magnetically linear? 2 2 1 1 5 7 5 x i i + + = 2 1 2 2 5 7 2 x i i + + = Problem 18 – Magnetically Linear System The flux linkage equations of a magnetically linear system may be expressed + + = 3 2 1 3 2 1 9 3 1 3 8 1 2 1 1 2 4 i i i x x Compute the force. Problem 19 – Review of Torque Concepts The front of a motor is facing you. Attached to the shaft of the motor is a 20 cm beam (it is centered on the shaft and oriented from left to right). On the right side of the beam a 2.5 Kg mass is located. Everything is stationary – the motor is producing the exact amount of torque to cancel that caused by the mass and beam. How much load torque is
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Unformatted text preview: produced and in what direction (clockwise or counterclockwise) Problem 20 Stepper Motor Characterization Your measure the series resistance / inductance of a stepper motor with a series LCR meter. As you rotate the machine the resistance is constant and is equal to 3.3 Ohms. The inductance varies between 10 mH and 140 mH. Also, the inductance has 8 maximum as you rotate the shaft through a revolution. What is the stator resistance, the number of rotor teeth, A ls L L + , and B L ? Note: you will not be able to separate ls L from A L with the given information. Problem 21 Stable Equilibrium Point Consider a variable reluctance stepper motor with 4 rotor teeth. Suppose that B L is 200 mH. The a- and c-phases are energized with a current of 1 A. Suppose further that the load torque is 0.1 Nm. Find the stable equilibrium point closest to zero....
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hw4 - produced and in what direction (clockwise or...

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