Showing papers on "Maximum power principle published in 1979"

Power from the sun

Abstract: Dr McKee (Physics Bulletin December 1978 p565) asserts that the maximum power available from fuel cells is limited to 200 W for a 1 m2 electrode which he attributes to 'a very low diffusion rate in electrolytes'. In actual practice fuel cells are often designed at around 1000 Wm−2 and values an order of magnitude higher have been demonstrated.

A high‐power CO2 waveguide laser

Abstract: A CO2 waveguide laser from which 39.5 W (51 W/m) has been obtained is described. These values are greater than any previously reported. Data on the temperature dependence of the output power are presented and discussed. An analysis was performed from which the small‐signal gain (0.22 cm−1) and saturation power (35 W) at conditions of maximum power output were obtained. It is shown that the assumption of distributed loss gives a better fit to the observed laser output than does that of concentrated loss at the mirrors.

Parametric power controller

Abstract: Disclosed is a vacuum furnace temperature controller for the stable regulation of temperature over a wide range of temperatures. The control loop includes a multiplier responsive to the desired temperature which modifies the overall loop gain and the maximum power which may be applied to the furnace heater as a function of the desired temperature.

Performance optimization of an MHD generator with physical constraints

Abstract: A method to optimize the Faraday MHD generator performance under a prescribed set of electrical and magnet constraints is described. The results of generator performance calculations using this technique are presented for a very large MHD/steam plant. The differences between the maximum power and maximum net power generators are described. The sensitivity of the generator performance to the various operational parameters are presented.

Motor drive unit for camera having variable winding speed characteristics

Abstract: A motor drive unit for a camera having variable winding speed characteristics functions so as to operate in a manner suited to environmental conditions such as temperature. This is done by changing the gear ratio from the motor to one of two values near the point of maximum efficiency and the point of maximum power output of the characteristic curve of the motors. Timer-controlled change of film frequency variation for providing a combined effect with the gear ratio is also disclosed.

A radio frequency generator for exciting electrodeless discharge lamps

Abstract: Important features of the instrument described are the simplicity of its design, the fact that no transmission cable is used between excitation coil and oscillator, and the ability to compensate for changes in the load, represented by the plasma in the discharge lamp. The generator operates at 149 MHz, which is much higher than the normal frequencies prescribed for the industrial, scientific and medical bands, but still allows coils to be used instead of cavities. The maximum power level of the generator is 192 W, while the typical power output to the discharge lamps is of the order of 60W.

Considerations for accurately determining the maximum power output of solar cells

Abstract: The most important single electrical parameter characterizing solar cell performance is Pm, the cell's maximum power output. In order to experimentally determine Pm it is necessary accurately to control both illumination and cell temperature during measurements. Two quite different measurement approaches can be used: an equilibrium method and a transient flash method. Both techniques are discussed in the paper in detail.

Method of qualifying diodes for a microwave power combiner

Abstract: The disclosed method qualifies diodes for microwave power combiners having a central cavity, and having N diode oscillator circuits spaced around the cavity for furnishing energy thereto It includes the steps of activating only one of the N oscillator circuits, and then measuring the frequency at which the diode in that circuit supplies maximum power to the cavity This power is measured by means of a probe having an electric field coupling of N11 with the cavity, where N11 equals N12 /√N, and where N12 is the corresponding electric field coupling that is used to remove power from the cavity when all N of the oscillator circuits are simultaneously activated These steps are repeated on each of the individual diodes to be tested The diodes which qualify for simultaneous use in the combiner are only those which have measured frequencies of maximum power lying within a predetermined frequency band

Elliptic polarized wave modulation control system

Abstract: PURPOSE:To secure the maximum power to reach the satellite by controlling the power distribution ratio of the variable power distributor via the driving circuit as well as controlling the phase of the variable phase shifter via the processor CONSTITUTION:The output of transmitter 1 is separated into two groups through variable power distribution board 2 The V component is delayed for the phase by 90 deg via 90 deg phase shifter 3, and the H component recives + or -alpha deg variation 4 The both components are then made to be orthogonal to each other via orthogonal mode compounder 5 to be supplied to reflector 7 via electromagnetic horn 6 Here, the receiving power state is known for the antenna mounted on the satellite through satellite telemetry receiver 8, and the obtained data undergoes the data process through data processor 12 Thus, the power distribution ratio of the variable power distributor is controlled via driving circuit 11, and the phase + or -alpha deg of variable phase shifer 4 is controlled via circuit 12 As a result, the power to reach the satellite can be maximized

A method for correlating performance data of a terrestrial solar cell array

Abstract: An analytical method was proposed for characterizing array power output, in the region of maximum power, as a function of environmental variables. The correlation provided a way of evaluating the output of an array under environmental conditions that differ from those encountered during testing. Power data obtained at one location was used to predict array performance at other locations.