Abstract: A method and apparatus for transition effects in digitally compressed motion video, such video complying with the MPEG-1 standard. Transitions between two frames of video are effectuated by selecting a FROM frame and a TO frame, generating a stream of bidirectionally dependent duplicator frames which vary in their motion vector references to the FROM frame and the TO frame according to a predefined pattern, placing the FROM frame in the past buffer of a decoder, placing the TO frame in the future frame of a decoder, feeding the stream of duplicator frames to the decoder, causing the duplicator frames to be displayed, and beginning normal playback of the video stream containing the TO frame at the TO frame position.

Abstract: An SF.sub.6 puffer interrupter switch includes one or more viewing windows located on the housing. The viewing windows are strategically located on a sidewall of the housing to allow all of the puffer interrupter assemblies within the housing to be viewed from one viewing window. The puffer interrupter assemblies that house the interrupting contacts are provided with clear puffer tubes to allow the operator to verify the position of the interrupting contacts within the puffer tubes from the viewing window located on the housing. The SF.sub.6 interrupter switch housing is pressurized. By assembling the viewing window assemblies from the inside of the housing, the positive pressure within the housing assists in sealing the viewing window assemblies to minimize the leakage of the SF.sub.6 gas. Additional viewing windows may be used to allow light inside the housing.

Abstract: A thrust spacer having resilient, upwardly angled tabs is provided to act as a variable spacer within a two-piece agitator, between an upper agitator portion and a lower agitator portion to prevent relative vertical movement between the two portions while permitting relative rotational movement therebetween. Each of the tabs is positioned adjacent to an opening larger than the tab to permit the tab to be compressed into the opening to provide a large degree of variability in the height of the tabs. The spacer also includes angled arms which engage with slots in the lower agitator portion to cause the spacer to rotate with the lower agitator portion.