GB1366377A - Supply monitoring apparatus - Google Patents

Abstract

1366377 Voltage monitoring INTERNATIONAL COMPUTERS Ltd 2 Oct 1972 [1 Oct 1971] 45772/71 Heading G1U Successive half-cycles of a full-wave rectified 11, Fig. 1, A.C. supply voltage 10 are compared with a pre-set lower threshold level 12, which, providing the supply potential is above the threshold level, therefore produces a series of output pulses, one for each half-cycle of the A. C. supply, each of which, after detection 13, discharges 14, i.e. resets, a ramp generator 15 so that its output does not rise high enough to set an amplitude responsive switch 16. The switch 16 has a plurality of outputs 18 which are sequentially energized as the input potential to the switch rises so that if one half-cycle is substandard the first lead 18 is energized, if two consecutive half-cycles are sub-standard the second lead 18 is energized, and if three consecutive half-cycles are sub-standard the third lead 18 is energized. Whenever a sub-standard half-cycle or group of half-cycles is detected, an appropriate print-out 20, with the time at which the sub-standard cycles occurred, is made. The single threshold level comparator 12 can be replaced by two or more comparators each set at a different level, so that, for example a record can be made of half-cycles that are 10%, 50% and 90% below their nominal amplitude.