. Elements of radio telephony . ystem in connection with analternating-current supply, the resulting output beingsmoothed out with suitable electrical filters consisting ofcondensers and inductance coils. Direct-ctxrrent Generators.—The construction of direct-,current generators up to 500 volts is so well known that onlycertain special types of machines will be considered requirement of all plate-voltage generators is that thevoltage should be as constant and as free from ripples as 34 ELEMENTS OF RADIO TELEPHONY possible. This requirement should be met by having asmany commutator seg
. Elements of radio telephony . ystem in connection with analternating-current supply, the resulting output beingsmoothed out with suitable electrical filters consisting ofcondensers and inductance coils. Direct-ctxrrent Generators.—The construction of direct-,current generators up to 500 volts is so well known that onlycertain special types of machines will be considered requirement of all plate-voltage generators is that thevoltage should be as constant and as free from ripples as 34 ELEMENTS OF RADIO TELEPHONY possible. This requirement should be met by having asmany commutator segments as possible ^nce the disturb-ance caused by the brushes passing from one segment to thenext may be thus reduced in the inverse proportion of thenumber of commutator segments. High-voltage generatorsusually require a large number of commutator segments forinsulational purposes also. For sets which are to be sup-plied from storage batteries a special type of combinationmotor and generator has been developed. This machine,. Fig. 15.—^Dynamotor for producing high-voltage direct current from alow-voltage direct-current supply. which is known as a dynamotor, has a single field andarmature, but two separate windings on the armature whichare insulated from one another. Each of these windings isbrought out to its own commutator, one of which is locatedon each end of the shaft. The low-voltage winding designedfor a value around 10 or 12 volts is connected to thestorage battery and acts as the motor, while the other wind-ing produces a high potential of about 350 volts for the platesupply. The field winding is supplied from the storagebattery. A similar piece of apparatus is sometimes used in VACUUM TUBE OSCILLATORS 35 airplane sets, the machine in this case acts as a double-current generator driven mechanically by an air fan andsupplies both plate and filament circuits simultaneously. For voltages up to 1000 volts a single-commutator machineis usually employed, above this value
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradio, bookyear1922
