GB321492A - Improvements in and relating to devices adapted to utilise wind power - Google Patents

Abstract

321,492. Cowan, E., W. L. Sept. 1, 1928. Dynamos, regulating; driving-arrangements.- A wind-driven generator is provided with a single field and two separate armatures and means for automatically connecting the armatures in series and parallel when the wind velocity is low and high respectively. Means may also be provided for controlling the field current and as an alternative to the series-parallel arrangement of two similar armature windings, two armature windings having different speed-volt characteristics and a common field may be employed. Or two separate dynamos with different speed-volt characteristics and a common or separate field, may be used. In these cases, the series -parallel switch which is used with the first-named arrangement is replaced by a selecting device operated by the output current to switch the load from one armature to the other. In the form shown, the two armature windings 3, 4 are brought out to the bus-bars 10, 7 across which the field coil 5 is connected in series with a rheostat SR. By means of a switch M, comprising a rocking-arm and mercury cups, the contacts M<1>, M<3> and M<2>, M<4> may be closed to parallel the armatures or the contacts M<5>, M' and M<6>, M<8> to connect the armatures in series. The switch is actuated by a magnet coil 17<a> energized from a low-voltage generator 23 connected to the main shaft, which machine also energizes the moving coil 24 of the field rheostat SR. This may comprise a number of mercury cups tapped to the resistance and an arm carrying a knife edge which makes contact with the mercury meniscus. An anti-flashing resistance 5a is connected across the field coils 5 and a resistance S is provided for doubling the range of the field regulator SR. The armatures are normally connected in series and as the wind velocity rises the increasing volts of the machine 23 cause the regulator SR to reduce the field current. At a limiting velocity, the switch M changes over to parallel connection and the field resistance is cut out, the resistance S being at the same time inserted in series with the operating coil 24. Further increase of velocity inserts field resistance until at a higher limit, when the velocity is dangerous, an overload coil a across the bus-bars causes the wind motor to shut down. As the wind falls, the sequence of connections is reversed. The arrangement shown includes a battery-charging system with the usual cut-out 28 for switching on when the requisite voltage is available.