Showing papers on "Power module published in 1971"

Modular power supply with indirect water cooling

Abstract: A modular power supply for converting alternating current to direct current for high power applications wherein the power modules are mounted inside a sealed cabinet and each module has its own fans to cool transformers and rectifiers therein. Also mounted inside the cabinet are cooling modules, each of which has its own fan and heat exchanger. Hot air from the power module outlets is cooled by the cooling modules and returned to the power module inlets. The capacity of the cooling modules is selected so that substantially atmospheric pressure exists in the cabinet at the power module inlets and outlets and so that the combined air flow through the cooling modules is substantially equal to the combined air flow through the power modules.

Multi-phase, 2-kilowatt, high-voltage, regulated power supply

Abstract: Development of a flight configured experimental power supply delivering 2 kw of conditioned power represents a concentrated effort at advancing the state-of-the-art in high voltage power supplies for space application. The power supply described herein was designed for use with the Jet Propulsion Laboratory (JPL) 20 cm Mercury Ion Thruster. However, its modularized design philosophy allows adaptation to various high voltage, high power requirements. Areas of principal concern are design of power and control circuits, performance parameters, packaging, efficiency, and weight.

Portable hair dryer

Abstract: A portable hair dryer comprises a flexible bonnet, a combined blower and heater power module for supplying heated air under pressure to the bonnet, and a control module for selecting the operating mode of the dryer. The power module is suspended against the back of the user by means of a pair of support straps which extend over the user's shoulders to the control module. By balancing the weights of the power and control modules, a stable condition is obtained which enables the user to perform other activities during the drying operation. The power cord of the dryer depends from the control module to assist in balancing the weights, and flexible electrical conductors in one of the support straps convey electrical power to the power module. The other support strap is removably attached to the control module to facilitate setting up and taking down the appliance. The bonnet includes an internal air duct formed by seams between its inner and outer liners for directing air to a central distribution plenum, and a plurality of radially-extending passageways similarly formed for distributing air from this plenum to the surrounding portions of the bonnet for even heat flow.

Effects of Trends in Large Steam Turbine Driven Generator Parameters on Power System Stability

Abstract: The trend in turbine-generator characteristics as unit sizes become larger is in an adverse direction from the standpoint of power system stability. Results of specific studies as well as a general rule of thumb for evaluating this effect are given. The effectiveness of independent pole switching and other control measures available to the system planner are shown.

345 MVA Fully Water-Cooled Synchronous Condenser for Dumont Station Part I. Application Considerations

Abstract: A brief historical review of the use of static capacitors and synchronous condensers for regulating power system voltage is made. Comparative costs are shown which demonstrate that the large synchronous condenser has a place on the large EHV power system. Application of the 345 mva fully water-cooled synchronous condenser on the American Electric Power System is described.

Power supply aspects of semiconductor equipment

Abstract: This article presents data concerning the often ``unmentioned'' influences of semiconductors upon power sources, other equipment, and the user. The influence of methods of power control and the resulting harmonics is considered in detail, including some new data on the effect of unbalanced firing angles. Also presented is information relative to metering accuracy, radio, telephone, and control-circuit interference, lamp flicker, and semiconductor influence, including the characteristics of a new RFI-free switching device. In addition, aspects of regulatory agencies are considered, and detailed references for further in-depth study are given.

A Rapid Digital Computer Solution for Power System Network Load-Flow

Abstract: Introducing the Self-Adjusting Accelerator, a completely new digital computer method of solving a power system network load-flow is presented. With no sacrifice in accuracy, a mathematically rigorous solution (employing A B C D1 constants) is obtained using less computer time than any other nodal iterative method.

Remote power supply units for vehicles

Abstract: A vehicular remote electric power supply accessory unit for connection to the electrical system of a motor vehicle to supply electrical power for the operation of electrical hand tools or other electrical power requiring units. The electrical power generating alternator of the electrical system of the vehicle is utilized as a source of power, and switching means is provided for connecting the power output of the alternator selectively to a remote power outlet receptacle and to the customary battery and electrical system circuity of the vehicle. The power output from the alternator is disconnected from the battery circuit while the remote unit is in operation. Means is provided for preventing overloading the voltage regulator of the electrical system of the vehicle from the remote circuit connection and for indicating that the remote circuit is in operation. Means is also provided for accommodating heavy current loads through the switching means.

Power supply system for and method of energizing multiple level loads

Abstract: A power supply for a direct current load that has two power level requirements senses the current requirements of the load and operates a high output inverter at high power requirements and a low output inverter at low power requirements. The high and low output inverters are designed for maximum efficiency in their respective power ranges and are connected through full wave rectifying bridges to the load. The high power inverter is maintained in an "off" position until the load current requirement is increased. Upon the increase in current, a sensing circuit and energy storage device activates a switch to energize the high power inverter to power the load as long as the current requirements remain above a selected level.

SERT II - Solar array power system

Abstract: The solar array power system placed into a sun-synchronous orbit on the SERT II (Space Electric Rocket Test) Spacecraft was capable of providing over 6 X 10 w-hr of electrical energy over a period of 6 months. The 56-v, 1100-w sectionoutput is provided directly to a powerconditioning unit with no batteries in the system. The 28-v, 180-w section provided the power to the spacecraft for housekeeping and auxiliary experiments. The deployment technique, which uses springs in each leaf joint to extend the folded array into a flat fixed position, and redundant electrical pyrotechnic circuits to enhance probability of deployment, is discussed.

2800 watt series inverter DC power supply

Abstract: A high efficiency, low weight silicon controlled rectifier power supply which supplies 28V @100A is described. The power supply operates from a conventional 3 phase 120/208Vdc (50 to 1600Hz) power source. The AC power source is converted directly to DC which powers two SCR inverters operating phase displaced up to 12.5kHz. The two inverter outputs are rectified and fed into a common output filter to complete the final power conversion step. Output metering and input/output circuit breakers are provided in a rack mounted unit designed for natural convection cooling. Efficient, high frequency operation of the inverter SCR's makes possible the high overall power supply efficiency and low weight. Extremely stale and accurate voltage regulation is implemented. Additional features are inherent short circuit capability and adjustable output current limiting. Several aspects of circuit design and performance are discussed.

A digital regulated solar array power module

Abstract: Digital regulated solar array module and performance characteristics of its electronic circuits

Power and liberty1

Abstract: THIS article examines some of the relations between power and liberty. It is concerned exclusively with the kind of power which an agent possesses in so far as he is able to affect the actions of others in accordance with his own intentions; this kind of power, and the principal forms which it can take, have been extensively discussed in Anthony de Crespigny’s article ‘Power and its Forms’.* This kind of power is to be related to the following four accounts of liberty: liberty as the absence of interference with behaviour, as not being prevented by other persons from doing what one wants to do, as being able to do what one wants to do, and as self-determination. In varying forms, these kinds of accounts have had widespread currency. It should be noted that no account of liberty is espoused in this article. My discussion is confined to pointing out some of the implications of de Crespigny’s analysis of power for the four accounts of liberty in question. It emerges from this discussion that each of these accounts embodies some troublesome ambiguities, and thus each of them is, at the least, inadequately formulated. Apart from this, however, these accounts are not criticized. By drawing out the implications of de Crespigny’s analysis of power, it would perhaps be possible to show that they are unsatisfactory. But to show this, it would be necessary to introduce material that is beyond the scope of this article. For example, it would be necessary to establish that any given implication is grounds for rejecting the relevant account of liberty, rather than grounds for rejecting de Crespigny’s analysis of power.

Microwave Power Transistors

Abstract: The industry offers microwave power transistors with ratings from 20 watts at 1 GHz to 5 watts at 3 GHz. The inclusion of broadband matching networks in the transistor package has yielded power amplifiers with several hundred MHz bandwidth. Solutions for some of the reliability problems; e.g., hot-spot formation, power imbalance, and metal migration, have been found.

15 KVA static uninterruptible power conditioner

Abstract: The Army needs a light weight, reliable and economical uninterruptible power conditioner (UPC) capable of converting those input voltages and frequencies from various power sources to power conforming to military standards. Only static UPC was assumed to have the potential to meet military objectives. The alternative approaches vary in degree of risk, cost, weight and performance growth potential. The circuitry and performance characteristics for three approaches are discussed. The limitations of existing solid state devices are discussed. Predictions of physical characteristics for future UPC utilizing these technologies and circuits are provided.

Solid state electronic control of A.C. motors in evaporative cooling

Abstract: Studies in field applications of evaporative cooling demon­ strate a need for more effective economic.temperature regulation throughout the cooling season. To evaluate a solid state electronic control device for temperature regulation, a comparison was made be-' tween the conventional control systems and the recently developed solid state electronic phase control power module. The purpose of this study was to determine the effectiveness of the solid state control in its application to actual field conditions. Three tests were conducted using evaporative coolers powered by split-capacitor motors in simulation of actual field applications. The first two were conducted at a practical load level, and the third as a" maximum performance test. , Two types of electric motors were compared with the permanentsplit-capacitor test motor to determine their suitability and capabil­ ity for use with the solid state control. The capacitor-start motor proved to have the best characteristics. '. ' The solid state power module proved to be effective under all conditions within the capacity of the cooler. It surpassed the conven­ tional on-off two-speed system in all realistic applications in main­ taining a constant inside maximum temperature. Results from this study show the power module coupled with permanent-split-capacitor, splitphase or capacitor-start motors is suitable for practical, field applications.