Abstract: A siren comprises a compressed air supply which is deflected by stationary deflectors to exit radially through stator ports. A rotor with spaced ports rotates between the stator and deflector thereby opening and closing the stator ports. Stationary vanes are disposed at circumferentially spaced locations, and constitute together with the deflector plate and stator and rotor housing, plenums. There are fewer rotor ports than stator ports, which generates an out-of-phase acoustical pattern which creates an acoustic combination from the stator ports of an acoustic output at a distance from the siren which is more uniform spatially. The thermoplastic seal between the stator and the rotor has minimal clearance under operating conditions having been run-in and plastically deformed at a temperature higher than for normal operation.

Abstract: An apparatus and method for verifying the accuracy of watt-hour meters at their operational site includes applying a phantom load to the meter and to a watt transducer. The relative watt hour readings of the meter are compared to the watt hours computed from the power to the watt transducer and represented as a percentage error of the meter. The phantom load is constituted by a loading transformer with optional load adjustments to take into account different loads to the meter and there are also adjustment means to take into consideration different meter characteristics. The meter watt hour reading is determined from an articulated light generating and receiving means mounted in alignment with the revolving disc so that light passes through the aperture in the disc to the receiving means and then signals the verifying apparatus to give an indication of the watt hour reading of the meter. Alternatively the reading is obtained manually.

Abstract: A siren comprises a compressed air supply which is deflected by stationary deflectors to exit radially through stator ports. A rotor with spaced ports rotates between the stator and deflector thereby opening and closing the stator ports. Stationary vanes are disposed at circumferentially spaced locations, and constitute together with the deflector plate and stator and rotor housing, plenums. There are fewer rotor ports than stator ports, which generates an out-of-phase acoustical pattern which creates an acoustic combination from the stator ports of an acoustic output at a distance from the siren which is more uniform spatially. The thermoplastic seal between the stator and the rotor has minimal clearance under operating conditions havign been run-in and plastically deformed at a temperature higher than for normal operation.

Abstract: Subsynchronous resonance is detected in an electric a.c. power supply system by determining changes in wave parameters of substantially successive half cycles and applying said changes as a relationship of said subsynchronous resonance. The parameter change measured is the wave period, and changes in the ratio of the difference of the period of positive and period of negative half cycles over the sum of the period positive and the period of negative half cycles is related to detection of subsynchronous resonance.

Abstract: An electrical energy diversion measurement device includes a first clip-on transformer for location about the power cable at high elevation in the zone of the weather guard or at underground manhole location where power supply enters the consumer's dwelling. A second clip-on transformer is simultaneously located about a cable passing through the watt power meter housing supplying power to the consumer. A digital measurement means is responsive to the current sensed by either the current transformers or simultaneously by the transformers and digitally displays the current of each or the difference between the sensed current as a representation of current difference and energy diversion.

Abstract: A siren comprises a compressed air supply which is deflected by stationary deflectors to exit radially through stator ports. A rotor with spaced ports rotates between the stator and deflector thereby opening and closing the stator ports. Stationary vanes are disposed at circumferentially spaced locations, and constitute together with the deflector plate and stator and rotor housing, plenums. There are fewer rotor ports than stator ports, which generates an out-of-phase acoustical pattern which creates an acoustic combination from the stator ports of an acoustic output at a distance from the siren which is more uniform spatially. The thermoplastic seal between the stator and the rotor has minimal clearance under operating conditions having been run-in and plastically deformed at a temperature higher than for normal operation.

Abstract: A luminaire shield, particularly for protecting street lights from breakage by vandals includes a laminate plate mounted in spaced relationship from the lens of the luminaire. Heat can thereby escape between an air gap and between the light source housing and the shield, and the shield extends beyond the lens with a tail portion covering the electrical converter (ballast) mounted within the luminaire housing, such that this is also protected.