GB1495288A - Operation condition displaying device - Google Patents

Abstract

1495288 Control of D.C. motors COPAL CO Ltd 13 Dec 1974 [14 Dec 1973] 54041/74 Heading H2J [Also in Division G3] A rotary indicator which is advanced at regular intervals when a motor 8 is energized has a series of indicator flaps 1 to show, for example, the days of the week, and at least one further flap 1-1, 1-8 which is displayed to indicate an abnormal condition such as low battery voltage. At a point of rotation of flap drum 2 corresponding to the abnormal condition indication a cam recess 16 causes blade 22 of switch SWa to move from contact 23 to contact 24. The motor drives the drum via a worm 7 and gears 4-6, gear 5 and a cam 9 making one rotation for each step of the drum. The cam 9 controls a further switch SWb which, once the motor has been started by a control pulse applied to an SCR, is closed to keep the motor running for a complete revolution of the cam. The motor circuit, Fig. 2, includes a transistor 25 which is turned ON by the SCR and held ON by the switch SWb. Signals from a battery check circuit are applied at terminals 28, 29 to keep transistors 26, 27 respectively OFF and ON while the battery is healthy. When the drum 2 reaches its fault indication position and blade 22 moves to contact 24 as described above, the motor remains energized since transistor 27 is ON, so that the fault indication flaps are passed over and the next day indication is given. If the battery voltage drops, the check circuit turns the transistors 26, 27 respectively ON and OFF so that the motor becomes energized and runs until lever 19 drops into cam recess 16 to change over the switch SWa; the drum 2 then stops with flaps 1-1, 1-8 displayed. In a modified control circuit, the battery check circuit controls a relay (31, Fig. 3, not shown) and the transistors 26, 27 are omitted.