An Electronic Master Clock Control System

Autor:	K. P. P. Nambiar, B. R. Prabhu
Rok vydání:	1971
Předmět:	Engineering Mains electricity business.industry Power inverter Electrical engineering Mains hum Computer Science Applications Theoretical Computer Science Control system Electronic engineering Inverter Master clock Electrical and Electronic Engineering business Crystal oscillator Electronic circuit
Zdroj:	IETE Journal of Research. 17:436-439
ISSN:	0974-780X 0377-2063
DOI:	10.1080/03772063.1971.11486867
Popis:	An electronic solid state master control system has been developed with a view to enable ordinary electric clocks to indicate the precise time independent of the mains frequency variation and the mains supply failure. The a.c. mains power is converted to d.c. which is again inverted to a constant frequency a.c. source using a silicon controlled rectifier power inverter of 500 VA rating and capable of driving 200 self-starting electric wall clocks. The inverter operating frequency is controlled by a signal derived from a highly stable crystal oscillator with an estimated average daily accuracy of 0·5 parts per million and associated transistorized scale down circuits. Hence the inverter output frequency is precise and is independent of the mains supply frequency. A standby d.c. supply to the inverter is provided by lead acid batteries which are normally kept float charged. Thus in the event of the mains supply failure the inverter and other control circuits continue to operate on standby d.c. without inter...
Databáze:	OpenAIRE
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