GB1057448A - Circuit arrangement for a no break generating set - Google Patents

Abstract

1,057,448. No break A.C. supply systems; electric converting systems. A.G. FœR INDUSTRIELLE ELEKTRONIK AGIE LOSONE BEI LOCARNO. Sept. 21, 1965 [Dec. 15, 1964], No. 40273/65. Headings H2F and H2H. A " no break " A.C. supply system comprises a transformer-rectifier unit 1, a battery charging disconnecting circuit 2, a floating battery 3, and a thyristor inverter 4 supplying a load 10 at any desired frequency through a " T " filter 9. The battery is charged through a thyristor 15 normally rendered conductive through a diode 16 and resistor 19, but when the battery potential reaches a determined value, a Zener diode 17 breaks down thus firing another thyristor 18 which connects the gate electrode of thyristor 15 to its cathode. The thyristors 97, 102 of the inverter 4 are fired by a circuit 6 comprising a quartz crystal 32 controlled oscillator, through frequency dividing circuits, e.g. 52-58, 62-70 in which, due to the time constant of C.R. networks, e.g. 56, 57, only the first and every, say, sixth pulses are effective giving a dividing factor of 5. The square wave output of circuit 6 at, say, 50 c.p.s. is passed to a firing circuit 8 comprising, for thyristor 102, components 78-86 which supplies a number of firing pulses to the thyristor 102 during each square wave positive half-cycle, the frequency being determined by the R.C. network 80, 83. Thyristor 97 is similarly supplied during each square wave negative half-cycle. A commutating circuit for the thyristors 97, 102 is provided as shown.