In order to keep efficient an electrospark machining, the discharge gap between an electrode and a work should be controlled by automatic electrode feeding apparatus. For this feeding apparatus, a continuous servomechanism generally had been used, however, the authors adopted an on-off servomechanism utilizing stepping motors, instead. Features of the stepping motor that the overshoot at stopping is very small and the response is very quick make it possible to present an on-off servomechanism without hunting. The stepping motor is of two phase type with mechanical oneway brake. For driving the stepping motor, flip-flop method, AC method and DC superposed AC method were developed. To investigate performances of the stepping motor-driven feeding apparatus, working tests were made by means of RC discharge circuit. The test results expressed by relationship between working speed and worked surface roughness indicate that the stepping motor-driven feeding servomechanism is effective by either flip-flop driving method or AC driving method.

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In general, conventional automatic optimizing techniques can be classified into two categories, the exploratory method and the predictive method using process models. These methods both have disadvantages. Namely, the former can not follow up and compensate for fast outer disturbances in the controlled system with large time lag, while the latter may settle into a nonoptimum point when the model does not picture the real characteristics of the controlled system. Presented in this paper are two new optimizing control schemes which use combination of the above two methods so that they compensate for the disadvantages each other. Especially, an application of model modification method, one of the two methods, to a hypothetical process is analyzed on an analog computer as to the setting time to an optimum point, relation between deviation of the settled point from the true optimum point and an accuracy of model, and the effect of execution time of computer. Also described is an experimentally-built optimizer that operates on the model modification scheme.

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A phase alternative type control transformer is similar to an induction regulator, but the former is controlled by D-C signal and has no moving part. It is composed of four magnetic circuits with three windings on each. These windings are primary, secondary and control windings. Primary windings are connected in series in the same polarity and are supplied by an A-C voltage source. Secondary windings are connected in series, too, but a half of them is in the contrary polarity and is connected to the load. Each two control windings are connected in series and are supplied by D-C control signal source. Load terminal A-C voltage is controlled by D-C control signal value and its phase is determined by D-C control signal polarity. Its analysis and experiments are given in this paper.

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It is generally believed that an accuracy of a balance utilizing a spring is deteriorated by the influence hysteresis. This paper intends to make it clear that a balance using a spring, if observed independent the principle of measurement, will come under a major influence of hysteresis when measurement made under a balance effected between the gravity and elasticity, while it will be little affected hysteresis if a spring is used as a lever fulcrum and measurement is made under a balance with standard weight. In the latter case, the main cause for dispersion in the case of knife-edge fulcrum is removed with the result that the dispersion may be minimized. Then, various constructions of the fulcrum which a lever is hung by the spring were classified and thus, their respective superiority or inferiority fulcrum in respect to sensitivity and load standing capacity was examined. As the result, an fulcrum of cross flexure was found to be superior because it fully satisfies all of these conditions required. Accordingly, a pendulum balance using such a fulcrum was experimentally manufactured with an application of the Roberval mechanism. Its dispersion, as anticipated, is far less than that of conventional balance using the knife-edge fulcrum.

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A new frequency dividing circuit composed of a ferroelectric condenser, an unijunction transistor and other accessories is able to be used for 1/2 to 1/10 frequency division of 50 to 2000 c/s if for experimental purpose. As this/circuit operates very stably and may be used for comparatively high frequency due to the development of manufacturing technics of ferroelectric condenser, it seems to be useful as a light weight compact frequency dividing circuit. It is used to count a pulse train, too.

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