GB462314A - Improvements relating to automatic electric cut-out devices - Google Patents

Abstract

462,314. Electromagnetic switches. C. A. V.-BOSCH, Ltd., and GLASER, W. H. Sept. 6, 1935, Nos. 24853 /35 and 865 /36. [Class 38 (v)] [Also in Group XXXV] An electromagnetically-operated cut-out for connecting a dynamo to a storage battery has arranged in parallel with its contacts a rectifier which itself is adapted to be arranged in series with the dynamo and battery, the rectifier being so connected that it allows current to flow freely from the dynamo to the battery. As shown in Fig. 1 the cut-out has the usual shunt and series windings d, e, the latter being brought into operation by closure of the cut-out contacts c. The rectifier f, which is preferably of the dry-plate type, is connected between the dynamo a and battery b in parallel with the cut-out the rectifier, being so connected as to permit current to flow freely from the dynamo to the battery. Thus current flows from the dynamo to the battery immediately the potential of the former exceeds that of the latter; and this current flow continues with increasing voltage of the dynamo until its voltage exceeds that of the battery sufficiently to operate the cut-out and close contacts c. Similarly with decreasing dynamo voltage current continues to flow from dynamo to battery after the cut-out has opened until the dynamo voltage falls below that of the battery. Thus a larger use of the dynamo is obtained and if the battery is being discharged, for example, through lamp circuits before the cut-out closes the presence of the rectifier is stated to minimise the potential difference that may exist between the dynamo and battery and so minimise the fluctuation in the brightness of lamps which may be in use at the instant the cut-out closes. To prevent slow leakage of the battery through the dynamo when the latter is at rest a switch g may be included in the rectifier circuit and may be operated simultaneously with the ignition switch. In a modified arrangement shown in Fig. 2 the shunt winding of the cut-out is dispensed with, a winding h being in series with the rectifier producing closure of the cut-out contacts when a predetermined current flow passes through the rectifier. The reduced current in this winding after the closure of the contacts assists the series coil in maintaining the cut-out in the closed position. Other arrangements are also described including a combination of the arrangements previously described and also an arrangement involving two successively actuated cut-outs. Instead of the switch g an electromagnetically-operated switch may be employed which automatically cuts the rectifier into circuit immediately the dynamo voltage rises above a predetermined low value.