| 摘要 |
<p>734,926. Substituting electrical sources in service ; brush gear for dynamo-electric machines. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Jan. 18, 1952 [Jan. 23, 1951], No. 1523/52. Classes 35 and 38 (4). A standby electricity supply apparatus for a load 2 such as an amplifier station in an electrical communication system, which load is normally supplied from a mains 1, comprises a generator 5 whose magnetic field is always present and which generator is normally driven from the mains by an electric motor 4 but in the event of mains failure is driven at first by inertia and thereafter by an electric motor 7 supplied from an emergency current source 10; a quick-acting relay 3 connecting the load 2 to the generator 5 instead of to the mains 1. Hence the motor 4 need be only small such as to drive the generator in its unloaded condition. The latter may have, as shown, a rotating field comprising one or more permanent magnets 11, or, not shown, it may have slip-rings connected through brushes to the load, a transformer being interposed in the latter connection whereby the no-load current thereof prevents glazing of the brushes during normal running. A fly-wheel 6 may be provided on the shaft 8 which interconnects the motor 4, generator 5 and the motor 7. The latter has a field which is always energized, comprising either a permanent magnet or a winding 9 supplied from the source 10; it may have a commutator 20 engaged only during mains failure by brushes 14 which during normal running are disengaged by a lifting device comprising levers 12, arms 15, and a solenoid 18, 19 energized by the mains 1. German Specification 721,448 is referred to.</p> |
