ASSIGNMENT

Assignment



Assignment

Introduction

Engineering is the practical application of science and math to solve problems, and it is everywhere in the world around you. From the start to the end of each day, engineering technologies improve the ways that we communicate, work, travel, stay healthy, and entertain ourselves.

Engineers are problem-solvers who want to make things work more efficiently and quickly and less expensively. From computer chips and satellites to medical devices and renewable energy technologies, engineering makes our modern life possible. In particular, electrical engineers and computer engineers have a wide range of study options and career paths that let them design, build, and manage those ideas into reality.

Answer # 1

Figure 1 is a block diagram of the electromechanical functional elements of the Speed Control System. The control of the Speed Control System is shown divided into 3 independent control subsystems, namely Wheel Control (Inner Gimbal and Rotor Assy.), Inner Gimbal Control and Outer Gimbal control. The Speed Control System was constructed to provide independent wiring for these three control subsystems. Power, command and monitoring was provided on a manually operated test panel such that each control subsystem could be operated alone or in combination for engineering development flexibility. The Wheel Control subsystem is made up of two 2 phase BDC Spin Motors and their associated Hall Commutation and speed control electronics, one for each phase. Each phase electronics package is independent of the other three (including wiring) for separate external CMG control during engineering studies. With this arrangement, wheel run-up can be accomplished with any two phases with an increase in run-up time. In addition, having attained speed, any one phase will hold speed to a degraded accuracy. Normal run-up is accomplished with two complete spin motor control channels (4 phases) and normal operation at speed is provided by one of the two spin motors and its two phases of electronics. External CMG manual monitoring provisions includes redundant IGRA cavity vacuum sensors, redundant spin bearing' thermisters, spin bearing vibration pickoffs and speed measurement from the Hall element electronics. Speed selection is externally set by application of one of the three set frequencies for H=1000, 2000, 3000 FPS (Speed = 4000, 8000, 12000 RPM).

Heater excitation is also externally applied as desired for engineering testing. Provision for rapid wheel run down (rather than a long power off coast down) was made in the manual test and control panel furnished with the SPEED CONTROL SYSTEM. The DC Brake switch disconnects the spin motor electronics 28V. DC power lines from their power sources and connects the lines across power resistors located in the test panel. Procedurally, at 1000 RPM the DC brake is to be turned off. Each Gimbal Control subsystem is made up of a two phase BDC Torquer and Tachometer, with their associated Hall commutation and gimbal rate control electronics. External CMG manual monitoring capability includes gimbal angle provided by the resolvers, gimbal rate provided by a brush type Tachometer (for engineering test) and motor rate from the BDC Tachometer ...